source: other-projects/gs3-webservices-java-client/trunk/src/GS3Fedora/org/greenstone/fedora/services/FedoraConnection.java@ 26171

/**
 *#########################################################################
 * FedoraConnection.java - works with the demo-client for Greenstone 3, 
 * of the Greenstone digital library suite from the New Zealand Digital 
 * Library Project at the  * University of Waikato, New Zealand.
 * <BR><BR>
 * Copyright (C) 2008 New Zealand Digital Library Project
 * <BR><BR>
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * <BR><BR>
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *########################################################################
 */

package org.greenstone.fedora.services;
import org.greenstone.gsdl3.util.GSXML;

import fedora.client.utility.AutoFinder;
import fedora.server.access.FedoraAPIAServiceLocator;
// The object for accessing FedoraAPI-A web services:
import fedora.server.access.FedoraAPIA; 

// The definitions for all complex fedora types:
import fedora.server.types.gen.MIMETypedStream;
import fedora.server.types.gen.RepositoryInfo;
import fedora.server.types.gen.FieldSearchResult;
import fedora.server.types.gen.FieldSearchQuery;
import fedora.server.types.gen.DatastreamDef;
import fedora.server.types.gen.ObjectFields;
import fedora.server.types.gen.Condition;
import fedora.server.types.gen.ComparisonOperator;
//import fedora.server.types.gen.*;

import javax.net.ssl.SSLHandshakeException;
import java.net.ConnectException;
import org.xml.sax.SAXException;
import java.io.UnsupportedEncodingException;
import java.io.IOException;
import javax.xml.parsers.ParserConfigurationException;
import java.net.MalformedURLException;
import java.rmi.RemoteException;
    
import java.io.StringReader;
import java.io.FileInputStream;
import java.io.File;
import java.util.TreeSet;
import java.util.Properties;
import java.util.Vector;

import java.awt.GridLayout;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import org.apache.log4j.Logger;
import org.greenstone.fedora.services.FedoraGS3Exception.AuthenticationFailedException;
import org.greenstone.fedora.services.FedoraGS3Exception.CancelledException;
import org.greenstone.fedora.services.FedoraGS3Exception.FedoraGS3InitFailureException;
import org.greenstone.fedora.services.FedoraGS3Exception.FedoraVersionNotSupportedException;
import org.greenstone.fedora.services.FedoraGS3Exception.NotAFedoraServerException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.*;

import org.xml.sax.InputSource;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;

/** Class that establishes a connection with Fedora's web services (via
 * Java stub classes for the same) and then provides methods to retrieve
 * Greenstone-specific data, such as the TOC, EX, DC,and Section 
 * datastreams of the Greenstone documents stored in Fedora's repository.
 * These datastreams are returned as Strings without any changes being
 * made to them.
 * @author ak19
*/
public class FedoraConnection implements FedoraGS3DL {
    /** The logging instance for this class */
    private static final Logger LOG = Logger.getLogger(
              FedoraConnection.class.getName());
    
    /** The version of fedora that is supported by class FedoraConnection */
        protected static final String SUPPORTED_VERSION = "3.3"; //"2.2.1";
                                     // 3.3 works with genericSearch version 2.2

    /* Some fixed strings of known literals */
    protected static final String GET = "/get/";
    
    // The DemoSOAPClient declares and uses the following as a static member  
    // Probably none of the APIA methods (web service methods) remembers   
    // state, that might explain why we can use it as a static member then.
    /** The object used to access the Fedora API-A web service methods */
    protected FedoraAPIA APIA; 

    /** Version of the running fedora server */
    protected String fedoraVersion;
    /** The location of the fedora server, usually of the form: protocol://host:port/fedora
     * e.g. (and default) http://localhost:8080/fedora */
    protected String baseURL; 
    
    /** The user-specified portAddressSuffix of the Fedora Access web services 
     * (endpoint URL in the WSDL), usually of the form 
     * http://localhost:8080/fedora/services/access 
     * Users can tell FedoraGS3 to try accessing that first by setting 
     * the "port.address.suffix" property in the properties file. 
     * FedoraGS3 itself will not write the portAddressSuffix currently used in
     * the file for next time, but leave whatever value was entered in the
     * properties file. The portAddress--not just suffix--currently in use (once
     * the FedoraAPIA handle has been instantiated) can be obtained through 
     * getPortAddressURL() method. */
    protected String portAddressSuffix;
    
    /** The part of the portAddress that comes after the baseURL. By default and
     * usually this is: "/services/access" */
    protected static final String defaultPortAddressSuffix = "/services/access";
    
    /** The preferred language of the display content */
    protected String lang;
    /** The maximum number of collections to retrieve */
    protected int maxresults; 
    /** DocumentBuilder used to create and parse XML documents */
    protected DocumentBuilder builder;
    
    /** Static method that returns the version of Fedora supported by this
     * class FedoraConnection. */
    public static String getSupportedVersion() { return SUPPORTED_VERSION; }
    /** The version of the running Fedora server, which may or may not
     * match the supported version. */
    public String getFedoraVersion() { return fedoraVersion; }
    
    /** @return the default language used to query for titles (and anything else
     * where there are multiple language options). Upon initialisation, this 
     * defaults to English. */
    public String getLanguage() { return lang; } 
    
    /** Sets the the default language used to query for titles (and anything else
     * where there are multiple language options). If the default language for any
     * query is not available, then English ("en") is used. If that's not available
     * then the first other available language is used.
     * @param lang - the two-letter language code to set the default language to.
    */
    public void setLanguage(String lang) { this.lang = lang; }
    
    /** The default maximum number of search results returned for a search. Upon
     * initialisation, this defaults to Java's Integer.MAX_VALUE. */
    public int getMaxResults() { return maxresults; }
    
    /** Set the default maximum number of search results returned for a search. 
     * @param maxresults - the new default maximum number of search results to 
     * be returned. */
    public void setMaxResults(int maxresults) { this.maxresults = maxresults; }
    
    /** Code for this constructor is from DemoSOAPClient.java. 
     * Instantiates the APIA handle using the protocol, host, port, fedora
     * server repository username and password.
     * @param host - the fedora server host (may be prefixed with http:// or  
     * https:// if parameter protocol is empty). If there's no protocol, and 
     * no protocol prefixed to the host, then the protocol defaults to http.  
     * @param protocol - either http or https (or empty "")
     * @param port - the port on which fedora is running.
     * @param fedoraServerUsername - the administrator username required to
     * access the fedora server's repository. ("fedoraAdmin" unless changed).
     * @param fedoraServerPassword - the fedora server repository's 
     * administrator password. If none was set on fedora installation, this
     * can be empty (""). */
    public FedoraConnection(String protocol, String host, int port, 
            String fedoraServerUsername, String fedoraServerPassword)
        throws ParserConfigurationException, MalformedURLException, 
            SSLHandshakeException, RemoteException, AuthenticationFailedException,   
            NotAFedoraServerException, ConnectException, Exception 
    {
        try {
            this.portAddressSuffix = "";
            init(protocol, host, Integer.toString(port), 
                fedoraServerUsername, fedoraServerPassword);
        } /*catch(RemoteException re) { //subclass of IOException
            throw re; 
        } catch(SSLHandshakeException ssle) { //subclass of IOException
            // this is also of type IOException
            throw ssle; 
        }*/ catch(IOException ioe) { // connected to the wrong server
            String exceptMsg = ioe.getMessage().toLowerCase();
            if(exceptMsg.indexOf("request failed") != -1 
                    || exceptMsg.indexOf("404") != -1) 
                throw new NotAFedoraServerException();
            else // the IOException is not due the cause we thought it was, so 
                throw ioe; // rethrow whatever other IOException was caught (which 
                    // could have been RemoteException or SSLHandshakeException  
                    // or some other cause)
        }
    }
    
    /** Default constructor which takes input from the user to get host, port, 
     * fedora username and password. 
     * It keeps looping to display authentication popup, until valid values are  
     * entered:
     * (a) if password is wrong, a RemoteException is thrown and popup reappears;
     * This popup keeps appearing until the password and username are correct (as
     * long as there's indeed a fedora server listening at the given host and port).
     * (b) SSLHandshakeException occurs: this happens EITHER when the user prefixed 
     * the 'https' protocol to the host string when it should have been 'http';
     * OR the ssl connection failed for some other reason. 
     * Allowing for the 1st case, the authentication popup is displayed just once
     * more. On the second (consec) attempt, the SSLHandshakeException is rethrown.
     * NOTE: if a fedora server at the protocol (https or http) isn't accessible, 
     * it takes a long time for the SSLHandshakeException to be thrown. 
     * (c) if the connection is refused, then a ConnectException is thrown. 
     * In that case, it's  
     * EITHER because the host and port values that were entered are wrong (and
     * the authentication popup dialog is redisplayed just once more allowing
     * the user to correct host/port values)
     * OR the entered host and part were right but the fedora server at this
     * host and port is not running. 
     * On the second consecutive attempt where a ConnectionException is thrown,
     * it's no longer processed but rethrown, as there's no use in redisplaying  
     * the authentication popup when the problem is not an authentication issue. 
     * (d) Another IOException (other than the SSLHandshakeException of (b))
     * occurs when there is indeed a server listening at the host and port  
     * entered, but it's not a Fedora server, because it is unable to process
     * Fedora requests. If the expected message is found in the exception, than
     * the authentication popup is displayed. However, other causes for an  
     * IOException are not handled. In such cases, the IOException is rethrown. 
     * (Note that IOException is not in the throws clause - other causes for 
     * it being unknown, it can be be considered as the more generic Exception.
    */
    public FedoraConnection()
        throws ParserConfigurationException, MalformedURLException, 
            CancelledException, ConnectException, RemoteException, 
            SSLHandshakeException, Exception
    {
        Properties properties = new Properties();
        // loop to display fedora server authentication popup to
        // get user input
        setInitialisationProperties(properties);
        properties = null; // finished
    }
    
    /** Single argument constructor that takes the name of the properties file
     * defining the values of the initialisation parameters required to
     * instantiate a FedoraConnection. These are fedora server username, password, 
     * host and port. If these values are not present in the file, they are set
     * to "" before showing the initialisation input dialog. 
     * @param propertyFile is the name of the properties file specifying the 
     * values for Fedora server username, password, host and port. */
    public FedoraConnection(File propertyFile)
        throws ParserConfigurationException, MalformedURLException, 
            CancelledException, ConnectException, RemoteException, 
            SSLHandshakeException, Exception
    {
        Properties properties = new Properties();
        // Load the properties from the given file
        try{
            if(propertyFile.exists()) { 
                properties.load(new FileInputStream(propertyFile));
            }
        } catch(Exception e) {
            // If the file didn't exist or could not be located,
            // then we just continue by creating empty properties
            LOG.warn("Exception loading from propertyFile " 
                    + propertyFile + ": " + e);
        }
        
        // Go through the process of showing the initialisation dialog
        setInitialisationProperties(properties);
        
        // Now let's save whatever values the user may have entered into the 
        // input dialog as the default values for next time the dialog shows
        try {       
            java.io.FileOutputStream out = new java.io.FileOutputStream(
                    propertyFile); // same file as properties loading file  
            // First make sure errormessage gets stored as "" and doesn't  
            // cause problems next time. 
            properties.setProperty("errormessage", "");
            // Don't save passwords
            properties.setProperty("password", "");
            // If the portAddressSuffix is in the file already, then it's
            // user-specified and we shouldn't change it. But if there is no
            // such property in the file, then create it and write it to the file
            // with an empty string value:
            String portSuffix = properties.getProperty("port.address.suffix");
            if(portSuffix == null) {
                properties.setProperty("port.address.suffix", "");
            }
            
            properties.store(out, "fedoraGS3 properties"); // write properties
            // Javadoc states that "The output stream remains open after this  
            // method (Properties.store) returns." So we close it here
            out.close();
        } catch(Exception e) {
            LOG.warn("Exception writing to propertyFile " 
                    + propertyFile + ": " + e);
        } 
        properties = null; // finished
    }
    
    /** Method that loops to display the dialog that retrieves the 
     * fedora server initialisation properties from the user. If there 
     * is a property file with values set already, it will display
     * the previously entered values by loading them from that file.
     * Otherwise, input fields in the dialog are empty.
     * @param properties the Properties Hashmap storing values for
     * username, password, host and port (and any errormessage). */
    protected void setInitialisationProperties(Properties properties) 
        throws ParserConfigurationException, MalformedURLException, 
            CancelledException, ConnectException, RemoteException, 
            SSLHandshakeException, Exception
    {
        // keep looping to display authentication popup, until valid values are  
        // entered (except when a ConnectionRefused Exception is caught - this
        // needs to be rethrown):
        boolean authenticated = true;
        // reset any error messages that may have been stored (should not be
        // the case, but if there had been any difficulty during storing, it
        // may not have written out an empty errorMessage)
        properties.setProperty("errormessage", "");
        do{
            // show the Authentication-popup:
            // By passing the HashMap Properties, user-updated values will
            // be persistent in the authentication-popup fields (rather than
            // reset to the default initial values).
            properties = showAuthenticationPopup(properties);
            String fedoraServerUsername = properties.getProperty("username", "");
            String fedoraServerPassword = properties.getProperty("password", "");
            String host = properties.getProperty("host", "");
            String port = properties.getProperty("port", "");
            //String protocol = host.startsWith("http") ? "" : "http://";
            String protocol = "http://";
            if(host.startsWith("http") || host.startsWith("https"))
                protocol = ""; 
            // NOTE THAT: if a fedora server at https:// is not accessible, 
            // it takes a long time for the authentication popup to reappear.
            
            try{
                this.portAddressSuffix 
                    = properties.getProperty("port.address.suffix", "");
                // Use the FedoraClient utility to get the SOAP stub for APIA.
                // This SOAP stub enables the client to connect to a Fedora 
                // repository via the API-A web service interface.
                init(protocol, host, port, 
                    fedoraServerUsername, fedoraServerPassword); 
                    // will throw Exception if it can't instantiate APIA
            
                // if no exception thrown in the initialisation statement above,
                // then we have been authenticated:
                authenticated = true;
            } catch(AuthenticationFailedException afe) {
                authenticated = false;
                properties.setProperty("errormessage", afe.getMessage());
            } catch(RemoteException e) { // causes could be various
                String reason = e.getMessage();
                if(e.getCause() != null) { 
                    // For instance, if a ConnectException indicating 
                    // 'Connection Refused' or a java.net.UnknownHostException
                    // caused the RemoteException
                    
                    // Strip out prefix "Nested exception is..." from the 
                    // encapsulating Exception's message, by using the Cause's
                    // message. Keep Exception classname to give it some context:
                    reason = e.getCause().getClass().getName() + ": " 
                        + e.getCause().getMessage();
                    // Give some more information if the connection was refused.
                    // (This can also happen when the Fedora server is not running)
                    if(e.getCause().getClass().equals(ConnectException.class)) {
                        reason += FedoraGS3Exception.connectionRefusedMessage;
                    } 
                }
                // if the message indicates that a server was running there,
                // then we tell the user it was not a Fedora server
                if(reason.toLowerCase().contains("404") 
                        || reason.toLowerCase().contains("request failed"))
                {
                    reason = NotAFedoraServerException.MESSAGE + "\n("+reason+")";
                }
                authenticated = false;
                properties.setProperty("errormessage", reason);
            } catch(ConnectException e) {
                properties.setProperty("errormessage", 
                    FedoraGS3Exception.connectionRefusedMessage);
                authenticated = false; 
            } catch(SSLHandshakeException ssle) { // SSLHandshakeException should 
                // be handled before IOException, as it's an IOException subclass.
                authenticated = false;
                properties.setProperty("errormessage", 
                    FedoraGS3Exception.sslHandshakeExceptionMessage);
                // we won't prefix the host with http for the user, as https 
                // might be right after all, and something else might have gone 
                // during the connection attempt instead.
                    //host = host.replace("https", "http"); //setting it for them
                    //properties.setProperty("host", host);
            } catch(IOException ioe) { // occurs when we try to connect to a 
                // host/port where some server other than Fedora's is listening 
                // (e.g. if we end up connecting to GS3's host and port).
                // In that case, we can get exception messages like a 404:
                // "Unable to instantiate FedoraConnection
                // java.io.IOException: Request failed [404 /fedora/describe]"
                // Test this by trying to connect to localhost at 9090 where GS3 is
                String exceptMsg = ioe.getMessage().toLowerCase();
                if(exceptMsg.indexOf("request failed") != -1 
                    || exceptMsg.indexOf("404") != -1) 
                {
                    properties.setProperty("errormessage", 
                        NotAFedoraServerException.MESSAGE
                        + "\n(" + ioe.getMessage() + ")");
                } else if(exceptMsg.indexOf("401") != -1
                    || exceptMsg.indexOf("500") != -1) 
                {
                    authenticated = false;
                    properties.setProperty("errormessage", ioe.getMessage());
                } else { // the exception occurred for some other reason, rethrow it 
                    throw ioe; 
                }   
            } 
        } while(!authenticated); // will keep showing popup until auhentication
                // and connection input values are valid
    }
    
    /** 
     * Static method that displays a popup to allow the user to provide Fedora  
     * authentication (username, pwd) and connection (protocol+host, port) details.
     * @param properties is a Properties HashMap where the property Keys which must
     * have been put in here in advance (even with "" Values if appropriate) are:
     * <pre>
     * - username
     * - password
     * - host (may - but need not - be prefixed with either of the protocols 
     *   "http://" and "https://"
     * - port
     * - errorMessage (displayed near the top of the popup dialog). Can be "".
     * </pre>
     * The values stored in the properties HashMap for the above property are  
     * initially displayed in the fields and the user can overwrite them.
     * This is useful in such cases where invalid values were entered and this
     * popup must be redisplayed to allow the user to correct their previous input.
     * @return the same HashMap Properties which was passed as parameter. */
    protected static Properties showAuthenticationPopup(Properties properties) 
        throws CancelledException 
    {
        // Retrieve all the properties -- defaults to "" if any are null
        JTextField usernameField = new JTextField(
                properties.getProperty("username", "fedoraAdmin")); 
        JTextField passwordField = new JPasswordField(
                properties.getProperty("password", "")); 
        JTextField hostField = new JTextField(
                properties.getProperty("host", "localhost")); 
        JTextField portField = new JTextField(
                properties.getProperty("port", "8080")); 
        
        JPanel panel = new JPanel(new GridLayout(4,2));
        panel.add(new JLabel("User Name"));
        panel.add(usernameField);
        panel.add(new JLabel("Password"));
        panel.add(passwordField);
        panel.add(new JLabel("Host")); 
        panel.add(hostField);
        panel.add(new JLabel("Port")); 
        panel.add(portField);
        
        String heading = "Fedora Server Admin Authentication:";
        String errorMessage = properties.getProperty("errormessage", "");
        if(!errorMessage.equals("")) {
            heading = "=> " + errorMessage + "\n\n" + heading;
        }
        int option = JOptionPane.showConfirmDialog(null, new Object[] {
            heading, panel},
            "Enter Network Password",
            JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
        
        if (option == JOptionPane.OK_OPTION) {
            String fedoraServerUsername = usernameField.getText();
            String fedoraServerPassword = passwordField.getText();
            String host = hostField.getText();
            String port = portField.getText();
            properties.setProperty("username", fedoraServerUsername);
            properties.setProperty("password", fedoraServerPassword);
            properties.setProperty("host", host);
            properties.setProperty("port", port);
        } else { // Cancel option
            throw new CancelledException();
        }
        return properties;
    }
    
    /** Init method that is called by the constructor to set some
     * important member variables including instantiating the APIA object
     * used to invoke the Fedora APIA web service operations. 
     * @param protocol can be http or https 
     * @param host is the name of the Fedora server host 
     * @param port is the port number (String form) of the Fedora server 
     * @param fedoraServerUsername is the user name to access the Fedora
     * Server 
     * @param fedoraServerPassword is the password needed to access the 
     * Fedora Server
    */
    protected void init(String protocol, String host, String port, 
            String fedoraServerUsername, String fedoraServerPassword) 
        throws ParserConfigurationException, MalformedURLException, 
            AuthenticationFailedException, RemoteException, Exception
    {
        // initialise member variables
        lang = ENGLISH;
        maxresults = Integer.MAX_VALUE; 
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        builder = factory.newDocumentBuilder();
        
        // (protocol is "" if host already contains protocol)
        if(!protocol.equals("") && !protocol.endsWith("://")) 
            protocol += "://";
        // now create baseURL = protocol://host:port/fedora
        this.baseURL = protocol + host + ":" + port + "/fedora";
        
        // Get the FedoraAPIA handle to/stub of the Fedora web services
        // New way of instantiating connection to Fedora is dependent on
        // fewer files of FedoraClient.jar
        FedoraAPIAServiceLocator serviceLocator 
            = new FedoraAPIAServiceLocator(fedoraServerUsername,
                           fedoraServerPassword);
        
        APIA = null;
        boolean isUserSpecifiedPortAddressSuffix = false;
        // try any portAddressSuffix specified by the user
        if(!this.portAddressSuffix.equals("")) {
            isUserSpecifiedPortAddressSuffix = true;
            this.createAPIA(serviceLocator, this.portAddressSuffix, 
                "user-specified", isUserSpecifiedPortAddressSuffix);
        }
        
        // If the user-specified portAddressSuffix failed or if there was none  
        // given, then APIA will be null, so we will try with the default 
        // portAddressSuffix. This time all exceptions will be passed on.
        if(APIA == null) {
            isUserSpecifiedPortAddressSuffix = false;
            this.createAPIA(serviceLocator, defaultPortAddressSuffix, 
                "default", isUserSpecifiedPortAddressSuffix);
        }
        
    }
    
    /** Tries to create the FedoraAPIA instance using the serviceLocator
     * and the given portSuffix. The APIA instance is obtained for the 
     * baseURL+portSuffix. Any exceptions are (processed and) rethrown
     * or, if the flag isUserSpecifiedPortAddressSuffix is true, then the
     * Remote Exception from AXIS that it can't find the target service to
     * invoke is ignored so that the caller can retry with the default port-  
     * address suffix first before giving up. */
    protected void createAPIA(FedoraAPIAServiceLocator serviceLocator, 
            String portSuffix, String messageInsert, 
            boolean isUserSpecifiedPortAddressSuffix)
        throws Exception
    {
        //String portSuffix = (isUserSpecifiedPortAddressSuffix) ? 
            //  this.portAddressSuffix : defaultPortAddressSuffix;
            
        try {
            LOG.debug( "Trying to connect to Fedora using the given" 
                + " baseURL and the " + messageInsert + " portAddress suffix:\n" 
                + baseURL + portSuffix);
            APIA = serviceLocator.getFedoraAPIAPortSOAPHTTP(
                    new java.net.URL(baseURL+portSuffix));
            // let's test whether we're authenticated (otherwise a 
            // RemoteException will be thrown to indicate that the  
            // password was incorrect.)
            RepositoryInfo repositoryInfo = APIA.describeRepository(); 
            // throws RemoteException if pwd wrong or for other reasons
            // in which case describeRepository() service is unavailable
            this.fedoraVersion = repositoryInfo.getRepositoryVersion();
            // If we come all the way here, no exceptions were thrown:
            this.portAddressSuffix = portSuffix; // store the one currently in use
        } catch(RemoteException re) {
            // if we're here, then APIA was unable to call the web service
            // If this was because the fedora authentication failed, then 
            // let's throw a custom exception 
            String message = re.getMessage().toLowerCase();
            // Looking for something Unauthorized(401)
            if(message.indexOf("unauthorized") != -1 
                    || message.indexOf("401") != -1) 
            {
                throw new AuthenticationFailedException();
            } else if(isUserSpecifiedPortAddressSuffix 
                && re.getMessage().contains(
                    FedoraGS3Exception.missingTargetService)) 
            { 
                LOG.warn("Failed to connect to Fedora APIA services at given"
                        + " port address:\n" + portSuffix 
                        + "\nException: " + re.getMessage());
                // APIA.describeRepository can throw a remote exception 
                // whereby AXIS says the target service is missing and can't 
                // be invoked (FedoraGS3Exception.missingTargetService)
                // Don't rethrow this, if AXIS can't find the user-specified 
                // portAddressSuffix, we will try with the default suffix next
                APIA = null; 
            } else { // if trying default portAddressSuffix or if any other 
                // RemoteException was generated (whose cause is something 
                // other than an authentication failure) rethrow it.
                throw re; 
            }   
        } catch(Exception e) { // Other Exceptions
            // Could possibly be a ServiceException when using ServiceLocator
            if(isUserSpecifiedPortAddressSuffix) {
                APIA = null; // we won't throw other exceptions yet until
                // we have tried the default PortAddressSuffix for the baseURL 
            } else {
                throw new FedoraGS3InitFailureException(e);
            }
        } 
    }
    
    /** Gets all greenstone collections. Searches for greenstone:*-collection.
     * Method getCollections() defaults to getting only those objects in fedora's  
     * repository whose pids are of the format greenstone:*-collection.
     * The use of AutoFinder and findObjects is shown in
     * fedora-2.2.1-src/src/java/fedora/client/search/ResultFrame.java
     * The Fedora-APIA's method definition of findObjects is:
     * <pre>
     * fedora-types:FieldSearchResult findObjects(
     *              fedora-types:ArrayOfString resultFields,
     *              xsd:nonNegativeInteger maxResults,
     *              fedora-types:FieldSearchQuery query )
     * </pre>
     * @see <a href="http://localhost:8080/fedora/search">The local fedora search page for how the search works</a>
     * @see <a href="http://www.fedora.info/definitions/1/0/api/Fedora-API-A.html">Fedora access API, API-A for method findObjects</a>
     * @see <a href="http://www.fedora.info/definitions/1/0/types/&#035;complexType_FieldSearchQuery_Link031D7D80">XML type definition of FieldSearchQuery</a> 
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/types/gen/FieldSearchQuery.html">Type definition of 2.2.1 FieldSearchQuery</a>
     * @see <a href="http://www.fedora.info/download/2.1.1/userdocs/server/serverdocs/fedora/server/search/FieldSearchQuery.html">does not apply: type definition of 2.1.1 FieldSearchQuery</a>
     * @see <a href="http://john.drc-dev.ohiolink.edu/browser/drc-core/trunk/src/java/edu/ohiolink/drc/drcdl/BrowseController.java?rev=462">BrowseController.java for an example</a> 
     *  
     * @return an array of Strings containing the pids of all collections 
     * matching the format greenstone:*-collection. 
    */
    public String[] getCollections() throws RemoteException 
    {
        // Available constructors:
        // FieldSearchQuery(java.util.List conditions)
        // FieldSearchQuery(java.lang.String terms) 
        final String queryStr = GREENSTONE_+WILDCARD+_COLLECTION;
        FieldSearchQuery query = new FieldSearchQuery();
        query.setTerms(queryStr);
        query.setConditions(null);
        // we'd like pid and title returned for each object
        // we pass maxResults=null to get all objects that match
        // (i.e. all collections)
        String[] pids = null;
        
        FieldSearchResult collection = AutoFinder.findObjects(
                APIA, new String[]{"pid", "title"}, maxresults, query);
        ObjectFields[] results = collection.getResultList();
        pids = new String[results.length];
        for(int i = 0; i < results.length; i++) {
            pids[i] = results[i].getPid();
        }
        return pids;
    }
    
    /** All objects (incl "greenstone:*" objects) in fedora - be they collections,   
     * top-level documents or document sections - have a DC datastream. This 
     * method returns the content (XML) of the DC datastream as it is stored in 
     * fedora's repository.
     * (The pid/DC call is one of the default fedora-system 3 disseminations.) 
     * Try an example of the form: http://localhost:8080/fedora/get/&lt;pid&gt;/DC
     * To obtain the DC/any datastream, we use method getDatastreamDissemination()
     * of the interface FedoraAPIA. This method returns a MIMETypedStream.
     * The method signature is:
     * MIMETypedStream getDatastreamDissemination(String pid, String dsID, String asOfDateTime)
     * where dsID = itemID (look at datastreams page of running fedora instance)
     * To access the XML content of the MIMETypedObject returned, we use its method
     * bytes[] getStream(), but when instantiating a String from this, we have to
     * use the String() contructor where we can specify the charset encoding (in 
     * this case, it must be UTF-8). Else getStream() returns gobbledygook.
     * @return a String version of the XML in the DC datastream for the fedora
     * object denoted by pid.
     * @param pid - the fedora persistent identifier for an item in the fedora
     * repository. 
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/access/FedoraAPIABindingSOAPHTTPSkeleton.html">FedoraAPIABindingSOAPHTTPSkeleton.java, the API-A web service stub class</a>
     * @see <a href="http://drc-dev.ohiolink.edu/browser/fedora-core/tags/upstream/src/test/junit/fedora/test/integration/TestAPIA.java?rev=575">TestAPIA.java, which contains an example of MIMETypedObject.getStream() usage.</a>
     * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html#String(byte[],%20java.lang.String)">constructor String(byte[], java.lang.String)</a>
     * @see <a href="http://java.sun.com/j2se/1.4.2/docs/api/java/nio/charset/Charset.html">Charset.java, for character sets and encoding</a> 
    */
    public String getDC(String pid) 
            throws RemoteException, UnsupportedEncodingException 
    {
        // an example at http://expanse.cs.waikato.ac.nz:9080/fedora/get/greenstone:demo-HASH23d1019b589e2ef6a680e3/DC
        // datastream ID, dsID = itemID, look at a running fedora 
        MIMETypedStream dcStream 
            = APIA.getDatastreamDissemination(pid, DC, null);
            //asOfDateTime = null to get the current version of the dataStream
        
        // need to set the charset encoding to UTF8
        return new String(dcStream.getStream(), UTF8);
    }
    
    /** All "greenstone:*" objects in fedora (be they collections be they 
     * collections, top-level documents or document sections) have an EX 
     * datastream. This method returns the content (XML) of the EX datastream as 
     * is. (It calls the default fedora-system 3 dissemination &lt;pid&gt;/EX.)
     * @return a String version of the XML in the EX datastream for the fedora
     * object denoted by pid.
     * @param pid - the fedora persistent identifier for an item in the fedora
     * repository.  
     * Use MIMETypedStream APIA.getDatastreamDissemination(pid, itemID, 
     * asOfDateTime).
     * Use String(bytes[], charset="UTF-8") to convert MIMETypedStream.getStream().
     * @see String getDC(String pid) throws Exception 
     * */
    public String getEX(String pid) 
            throws RemoteException, UnsupportedEncodingException 
    {
        MIMETypedStream exStream = APIA.getDatastreamDissemination(pid, EX, null);
            //asOfDateTime = null to get the current version of the dataStream
        
        // need to set the charset encoding to UTF8
        return new String(exStream.getStream(), UTF8);
    }
    
    /** Some "greenstone:*" top-level documents in the fedora repository (but not 
     * greenstone collections or document sections) have a DLS metadata datastream. 
     * This method returns the content (XML) of the DLS datastream as is. (It calls 
     * the default fedora-system 3 dissemination &lt;pid&gt;/DLS.)
     * @return a String version of the XML in the DLS datastream for the fedora
     * object denoted by pid, or "" if the document given by pid has no DLS datastream.
     * @param pid - the fedora persistent identifier for an item in the fedora
     * repository.  
     * Use MIMETypedStream APIA.getDatastreamDissemination(pid, itemID, 
     * asOfDateTime).
     * Use String(bytes[], charset="UTF-8") to convert MIMETypedStream.getStream().
     * @see String getDC(String pid) throws Exception 
     * */
    public String getDLS(String pid) 
            throws RemoteException, UnsupportedEncodingException 
    {
        MIMETypedStream dlsStream = null;
        // If there is no DLS datastream, it throws an exception (whose class 
        // fedora.server.errors.DatastreamNotFoundException can't be imported 
        // here (it's not in the client side fedora.server.* package, but on 
        // the server side package of that name):
        try{
            dlsStream = APIA.getDatastreamDissemination(pid, DLS, null);
                //asOfDateTime=null to get the current version of the dataStream
        } catch(RemoteException e) {
            //These two don't work:
            //if(e.getCause().getClass().getName().equals("fedora.server.errors.DatastreamNotFoundException"))
            //if(e.getCause().getMessage().contains("fedora.server.errors.DatastreamNotFoundException"))
            
            if(e.getMessage().contains("fedora.server.errors.DatastreamNotFoundException")) 
            {   // there is no DLS data stream for this document
                return "";
            }
            else { // different problem, exception due to different cause
                throw(e);
            }
        }
        if(dlsStream == null) 
            return "";
        // need to set the charset encoding to UTF8
        return new String(dlsStream.getStream(), UTF8);
    }
    
    /** All "greenstone:*" objects in fedora (be they collections or documents) 
     * have a TOC datastream, unless they have only 1 section (SECTION1). 
     * This method returns the content (XML) of the TOC datastream as is.
     * (Calls default fedora-system 3 dissemination &lt;pid&gt;/TOC.)
     * @return a String version of the XML in the TOC datastream for the fedora
     * object denoted by pid.
     * @param pid - the fedora persistent identifier for an item in the fedora
     * repository. 
     * Use MIMETypedStream APIA.getDatastreamDissemination(pid, itemID, 
     * asOfDateTime)
     * Use String(bytes[], charset="UTF-8") to convert MIMETypedStream.getStream()
     * @see String getDC(String pid) throws Exception 
     * */
    public String getTOC(String pid) 
        throws RemoteException, UnsupportedEncodingException 
    {
        try {
        MIMETypedStream tocStream = APIA.getDatastreamDissemination(pid, TOC, null);
            //asOfDateTime = null to get the current version of the dataStream
        // need to set the charset encoding to UTF8
        return new String(tocStream.getStream(), UTF8);
        } catch(RemoteException re) {
        // if TOC does not exist, then it means there is only 1 section, dsID: SECTION1
        return new String("<Section id=\"1\"></Section>".getBytes(), UTF8); //set charset
        }       
    }
    
    /** @return the &lt;name&gt;s (in greenstone:&lt;name&gt;-collection) 
     * for the collections indicated by collPIDs. 
     * @param collPIDs - an array of Strings denoting the pids for greenstone
     * collections stored in the fedora repositoryl. These should be of the
     * format "greenstone:&lt;collectionName&gt;-collection". */
    public String[] getCollectionNames(String[] collPIDs) {
        String[] collNames = new String[collPIDs.length];
        for(int i = 0; i < collPIDs.length; i++) 
            collNames[i] = getCollectionName(collPIDs[i]);
        return collNames;
    }
    
    /** @return "greenstone:&lt;name&gt;-collection" for all &lt;name&gt;s
     * in the parameter collNames.
     * @param collNames - a list of names of greenstone collections
     * stored in the fedora repository. */
    public String[] getCollectionPIDs(String[] collNames) {
        String[] collPIDs = new String[collNames.length];
        for(int i = 0; i < collNames.length; i++) 
            collPIDs[i] = getCollectionName(collNames[i]);
        return collPIDs;
    }
    
    /** @return greenstone:&lt;name&gt;-collection for the&lt;name&gt; 
     * denoted by parameter collName.
     * @param collName - the name of a greenstone collection stored 
     * stored in the fedora repository. */
    public String getCollectionPID(String collName) {
        return GREENSTONE_+collName+_COLLECTION;
    }
    
    /**
     * Gets the title of the collection denoted by the given collection's pid by
     * retrieving the title metadata for it from the collection's EX datastream.
     * @return the title (in the default language, else English, else the
     * first title found) for the particular collection denoted by its PID. 
     * @param collPID is the pid of a greenstone collection in the fedora 
     * repository. */
    public String getCollectionTitle(String collPID) 
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException
    {
        String title = null; // has to be null initially, we do a check on it
        // Parse the EX datastream (XML), and in its DOM, find the 
        // <ex:metadata name="collectionname" qualifier="en">title</ex:metadata>
        // There might be one OR several of those with attribute 
        // name="collectionname". If there's only one, then get that. 
        // If there are several, there would possibly a be qualifier attribute,
        // in which case get qualifier=lang (where lang is the member variable)
        // If there is no qualifier with the requested language, then get the 
        // english one which is likely to be there, else return the title for 
        // the first collectionname .
        
        MIMETypedStream exdata
            = APIA.getDatastreamDissemination(collPID, EX, null);
        String exStream = new String(exdata.getStream(), UTF8);
        
        InputSource source = new InputSource(new StringReader(exStream));
        Document doc = builder.parse(source);
        Element docEl = doc.getDocumentElement(); // docEl=<ex:ex></ex:ex>
        NodeList children = docEl.getChildNodes();
        
        String firstName = ""; 
        String englishName = "";
        for(int i = 0; i < children.getLength(); i++ ) {
            Node n = children.item(i);
            if(n.getNodeType() == Node.ELEMENT_NODE) {
                Element e = (Element)n;
                if(e.hasAttribute(NAME) 
                        && e.getAttribute(NAME).equals(COLLECTIONNAME)) {
                    firstName = FedoraCommons.getValue(e);
                    if(!e.hasAttribute(QUALIFIER)) {
                        title = FedoraCommons.getValue(e); 
                        break;
                    }
                    else if(e.getAttribute(QUALIFIER).equals(lang)) {
                        title = FedoraCommons.getValue(e);
                        break;
                    } else if(e.getAttribute(QUALIFIER).equals(ENGLISH)) {
                        englishName = FedoraCommons.getValue(e);
                    }
                }
            }
        }
        
        // if the title is still not set to that of the requested language,
        // then try setting it to the collection name in English. If English
        // isn't available, then set it to the first collection name provided
        // (in whichever language).
        if(title == null) {
            title = englishName.equals("") ? firstName : englishName;
        }
        doc = null;
        return title;
    }
    
    /** @return the collection titles for all the collections indicated by
     * collPIDs. 
     * @param collPIDs - a list of pids identifying greenstone collections 
     * stored in the fedora repository. */
    public String[] getCollectionTitles(String[] collPIDs)
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException
    {
        String[] titles = new String[collPIDs.length];
        
        // parse each EX datastream (XML) which contains the gs3-extracted meta.
        for(int i = 0; i < collPIDs.length; i++) {
            titles[i] = getCollectionTitle(collPIDs[i]);
        }
        return titles;
    }
    
    /** @return the title metadata for the given doc objects of a collection. 
     * These titles are returned in the same order as the given docIDs. 
     * (The docPIDs already contain the collection name anyway.) 
     * @param docPIDs - a list of pids identifying documents stored in the 
     * fedora repository. */
    public String[] getDocTitles(String[] docPIDs) 
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException 
    {
        String[] titles = new String[docPIDs.length];
        for(int i = 0; i < docPIDs.length; i++) {
            titles[i] = getDocTitle(docPIDs[i]);
        }
        return titles;
    }
    
    /** Gets the title metadata for a particular doc object in a collection
     * denoted by docPID. The docPID already contains the collection name. 
     * @return the title for the fedora document item denoted by docPID
     * @param docPID is the pid of the document in the fedora repository 
     * (docPID is of the form greenstone:&lt;colName&gt;-&lt;doc-identifier&gt; */
    public String getDocTitle(String docPID) 
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException
    {
        // We need the extracted metadata file, and find its  
        // documentElement's child
        // <ex:metadata name="Title">sometitle</ex:metadata>
        // where the title we return is sometitle
        
        String title = "";
        MIMETypedStream exdata
            = APIA.getDatastreamDissemination(docPID, EX, null);
        String exStream = new String(exdata.getStream(), UTF8);
        return getTitle(exStream); 
    }
    
    /** Given a string representation of a document's or document section's  
     * EX datastream -- which is a greenstone extracted metadata XML file -- 
     * of the form:
     * &lt;ex&gt;
     * &lt;ex:metadata name="Title"&gt;sometitle&lt;/ex:metadata&gt;
     * &lt;ex:metadata name="..."&gt;....&lt;/ex:metadata&gt;
     * ...
     * &lt;/ex&gt;
     * This method finds the &lt;ex:metadata&gt; where the name="Title" and
     * returns the value embedded in that element ('sometitle' in
     * the example above). 
     * @return the title metadata of the document/document section whose EX 
     * datastream is passed as parameter
     * @param exStream the EX datastream in String form of the document or 
     * document section. */
    protected String getTitle(String exStream) 
        throws SAXException, IOException 
    {
        String title = "";
        InputSource source = new InputSource(new StringReader(exStream));
        Document doc = builder.parse(source);
        Element docEl = doc.getDocumentElement(); // docEl=<ex:ex></ex:ex>
        NodeList children = docEl.getChildNodes();
        
        // Cycle through all the *element* children of <ex:ex></ex:ex>
        // which are all of the form:
        // <ex:metadata name="somename">somevalue</ex:metadata>
        // Find the one where name="Title", its value is the title 
        for(int i = 0; i < children.getLength(); i++ ) {
            Node n = children.item(i);
            if(n.getNodeType() == Node.ELEMENT_NODE) {
                Element e = (Element)n;
                if(e.hasAttribute(NAME) 
                        && e.getAttribute(NAME).equals(TITLE)) {
                    title = FedoraCommons.getValue(e);
                        break;
                }
            }
        }
        return title;
    }
    

    /** Used to obtain the dc:title value (hashID) of the DC stream of a digital
     * object whose fedoraID is of a special sort: greenstone-http:<colname>-id. */
    protected String getDCTitle(String fedoraPID) 
    throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException
    {
    String title = "";
    MIMETypedStream dcdata = APIA.getDatastreamDissemination(fedoraPID, DC, null);
    if(dcdata == null || dcdata.equals("")) {
        return title;
    }
    String dcStream = new String(dcdata.getStream(), UTF8);
    
    InputSource source = new InputSource(new StringReader(dcStream));
    Document doc = builder.parse(source);
    Element docEl = doc.getDocumentElement(); // docEl=<oai_dc:dc></oai_dc:dc>
    NodeList children = docEl.getElementsByTagName("dc:title");
    if(children != null && children.getLength() > 0) {
        Node n = children.item(0); // <dc:title>
        Element e = (Element)n;
        title = FedoraCommons.getValue(e);
    }
    return title;
    }

    /** @return the title metadata for the given document sections. 
     * These titles are returned in the same order as the given docPIDs
     * and associated sectionIDs. 
     * (The docPIDs already contain the collection name anyway.) 
     * @param docPIDs - a list of pids identifying documents stored in the 
     * fedora repository. 
     * @param sectionIDs - a list of sectionIDs identifying individual sections
     * of documents stored in the fedora repository whose titles are requested. */
    public String[] getSectionTitles(String[] docPIDs, String[] sectionIDs) 
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException 
    {
        String[] titles = new String[docPIDs.length];
        for(int i = 0; i < docPIDs.length; i++) {
            titles[i] = getSectionTitle(docPIDs[i], sectionIDs[i]);
        }
        return titles;
    }
    
    /** @return the title metadata for the given document section. 
     * (The docPID already contain the collection name anyway.) 
     * @param docPID - a pid identifying a document in the fedora repository. 
     * @param sectionID - the sectionID of the section of the 
     * document whose title is requested. */
    public String getSectionTitle(String docPID, String sectionID) 
        throws UnsupportedEncodingException, RemoteException, 
            SAXException, IOException  
    {
        String ex = this.getSectionEXMetadata(docPID, sectionID);
        return getTitle(ex);
    }
        
    /** Searches the fedora repository for all greenstone:&lt;colPID&gt;* and 
     * returns the PIDs of the data objects found, with the exception of 
     * greenstone:&lt;colPID&gt;-collection, which is not a document but a 
     * collection PID.
     * That is, pids of objects whose pid is greenstone:&lt;colName&gt;* 
     * (but not greenstone:&lt;colName&gt;-collection itself, because that represents  
     * the collection and not an object of the same collection) are returned.
     * All pids that do not map to a collection are assumed to be documents!  
     * @return a list of the pids of all the (doc) objects in a collection. 
     * @param colPID is the pid of the greenstone collection stored in
     * the fedora repository. */
    public String[] getCollectionDocs(String colPID) 
        throws RemoteException 
    {
        String colName = getCollectionName(colPID); 
        //LOG.debug("colName: " + colName);
        
        // Search fedora objects for pid=greenstone:<colName>-*
        final String queryStr = GREENSTONE_+colName+HYPHEN+WILDCARD; 
                // searches for "greenstone:"+colName+"-*";
        FieldSearchQuery query = new FieldSearchQuery();
        query.setTerms(queryStr);
        query.setConditions(null);
        String[] pids = null;
        
        FieldSearchResult objects = AutoFinder.findObjects(
                APIA, new String[]{"pid", "title"}, maxresults, query);
        ObjectFields[] results = objects.getResultList();
        
        // NEED TO SKIP ANYTHING THAT ENDS IN "-collection" because 
        // that's not a document object:
        pids = new String[results.length-1]; // not storing collection object
        int index = 0; // keeps track of docPid index
        for(int i = 0; i < results.length; i++) {
            // check it's not a collection object
            if(!results[i].getPid().endsWith(_COLLECTION)) {
                pids[index] = results[i].getPid();
                index++;
            }
        }
        
        return pids;
    }

    /** Given the pid of a document fedora data object, this method will return 
     * all itemIDs that are part of that data object and are Sections. For further
     * information see interface Comparable (implemented by String), SortedSet 
     * and TreeSet. 
     * @return an array of itemIDs of the Sections of the document, 
     * indicated by docPID, in ascending order. These are of the form: "SECTION1.*"
     * @param docPID is a fedora pid identifying a greenstone document object. 
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/access/FedoraAPIABindingSOAPHTTPSkeleton.html">FedoraAPIABindingSOAPHTTPSkeleton.java stub class for the API-A web services</a>
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/types/gen/DatastreamDef.html">DatastreamDef.java</a>
     * @see <a href="http://dltj.org/2006/12/fedora-batch-processing/">Fedora batch processing</a>
    */
    public String[] getSectionNames(String docPID) throws RemoteException {
        // DatastreamDef[] listDatastreams(
            // java.lang.String pid, java.lang.String asOfDateTime)
        
        // listDatastreams returns information on each item (including itemID=dsID)  
        // in the document object indicated by docPID
        
        // Need to give an object version number, because null for asOfDateTime  
        // does not return any datastreams!
        String[] times = APIA.getObjectHistory(docPID);
        
        DatastreamDef[] datastreams = APIA.listDatastreams(
                docPID, times[times.length-1]);
        
        // TreeSet is a SortedSet. We're going to put Strings into it, 
        // and Strings implement interface Comparable already.
        TreeSet orderedList = new TreeSet();  //TreeSet(new RankComparator())
        for(int i = 0; i < datastreams.length; i++) {
            String itemID = datastreams[i].getID();
            if (itemID.startsWith("SECTION"))
                orderedList.add(itemID);
        }

        String[] sectionNames = new String[orderedList.size()];
        orderedList.toArray(sectionNames);
        orderedList = null;
        return sectionNames;
    }
    
    /** Given the pid of a document fedora data object, this method will return all
     * itemIDs that are part of that data object and are Sections, but just the 
     * Section numbers are returned. For further information see interface Comparable
     * (implemented by String), SortedSet and TreeSet. 
     * @return an array of itemIDs of the Section numbers of the document 
     * indicated by docPID, in ascending order. Return values are of form: "1.*".
     * @param docPID is a fedora pid identifying a greenstone document object.
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/access/FedoraAPIABindingSOAPHTTPSkeleton.html">FedoraAPIABindingSOAPHTTPSkeleton.java stub class for the API-A web services</a>
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/types/gen/DatastreamDef.html">DatastreamDef.java</a>
     * @see <a href="http://dltj.org/2006/12/fedora-batch-processing/">Fedora batch processing</a>  
    */
    public String[] getSectionNumbers(String docPID) throws RemoteException {
        String[] times = APIA.getObjectHistory(docPID);
        
        DatastreamDef[] datastreams 
            = APIA.listDatastreams(docPID, times[times.length-1]);
        //Vector v = new Vector(datastreams.length);
        TreeSet orderedList = new TreeSet();
        
        for(int i = 0; i < datastreams.length; i++) {
            String itemID = datastreams[i].getID();
            if (itemID.startsWith("SECTION")) {
                //int index = SECTION.length();
                //itemID = itemID.substring(index);
                itemID = removePrefix(itemID, SECTION);
                orderedList.add(itemID);
            }
        }

        String[] sectionNumbers = new String[orderedList.size()];
        orderedList.toArray(sectionNumbers);
        orderedList = null;
    
        return sectionNumbers;
    }   
    
    /** @return the titles for the document sections denoted by the parameters.
     * @param docPID is a fedora pid identifying a greenstone document object.
     * @param sectionIDs is a list of identifiers identifying sections in the
     * document denoted by docPID, whose titles need to be returned. Each 
     * sectionID may sectionID may be either a section name (e.g. SECTION1.5.1) 
     * or a section number (eg. 1.5.1). */
    public String[] getTitles(String docPID, String[] sectionIDs)
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException 
    {
        String[] titles = new String[sectionIDs.length];
        for(int i = 0; i < titles.length; i++)
            titles[i] = getTitle(docPID, sectionIDs[i]);
        return titles;
    }
    
    /** @return the title for the document section denoted by the parameters.
     * @param docPID is a fedora pid identifying a greenstone document object.
     * @param sectionID identifies the particular section in the document denoted
     * by docPID, whose title needs to be returned. The sectionID may be either a  
     * section name (e.g. SECTION1.5.1) or a section number (eg. 1.5.1). */
    public String getTitle(String docPID, String sectionID) 
        throws RemoteException, UnsupportedEncodingException, 
            SAXException, IOException 
    {
        // Compose the itemID for the EX data stream from the number in the
        // sectionID:
        String exID = removePrefix(sectionID, SECTION);
        exID = EX+convertToMetaNumber(exID);
        
        // Retrieve the extracted metadata stream (EX, in XML) for the given
        // section
        String exStream = getItem(docPID, exID);
        
        // Extract the title from the XML, look for:
        // <ex:ex><ex:metadata name="Title">title</ex:metadata></ex:ex>
        InputSource source = new InputSource(new StringReader(exStream));
        Document doc = builder.parse(source);
        Element docEl = doc.getDocumentElement(); // docEl=<ex:ex></ex:ex>
        NodeList children = docEl.getElementsByTagName(
                EX.toLowerCase()+COLON+METADATA); // <ex:metadata>
        for(int i = 0; i < children.getLength(); i++) {
            Element e = (Element)children.item(i);
            if(e.hasAttribute(NAME) && e.getAttribute(NAME).equals(TITLE))
                return FedoraCommons.getValue(e); // extract and return the title
        }
        return ""; // if we got here, then we couldn't find a title
    }
    
    /** @return the section's XML (as a String) as it is stored in fedora. 
     * Works out if sectionID is a sectionName or sectionNumber.
     * @param docPID - a fedora pid identifying a greenstone document object.
     * @param sectionID - identifyies the particular section in the
     * document denoted by docPID, may be a section name or number. */
    public String getSection(String docPID, String sectionID) 
        throws RemoteException, UnsupportedEncodingException
    {
        if(!sectionID.startsWith(SECTION)) // then it has only section number
            sectionID = SECTION+sectionID;
        
        String sectionXML = this.getItem(docPID, sectionID);
        return sectionXML; 
    }
    
    /** @return the required section's DC metadata XML datastream.
     * @param docPID - a fedora pid identifying a greenstone document object.
     * @param sectionID - identifyies the particular section in the
     * document denoted by docPID, may be a section name or number. */
    public String getSectionDCMetadata(String docPID, String sectionID)
        throws RemoteException, UnsupportedEncodingException
    {
        String dcID = removePrefix(sectionID, SECTION); 
                // ensure we have just the section number
        dcID = DC+convertToMetaNumber(dcID); // itemID of DC = DC + number 
        
        // now get the DC datastream for that number
        String dcXML = this.getItem(docPID, dcID);
        return dcXML; 
    }
    
    /** Returns the section EX metadata XML datastream for SectionID which may be 
     * a section name or number. Currently a few EX files are named awkwardly:
     * the EX file for section 1.* is actually associated with datastream EX.*. 
     * But subsequent EX datastreams are named appropriately: for instance, 
     * EX2.1.1 matches with section 2.1.1 
     * @return the required section's EX metadata XML datastream.
     * @param docPID - a fedora pid identifying a greenstone document object.
     * @param sectionID - identifyies the particular section in the
     * document denoted by docPID, may be a section name or number. */
    public String getSectionEXMetadata(String docPID, String sectionID)
        throws RemoteException, UnsupportedEncodingException
    {
        String exID = removePrefix(sectionID, SECTION);
        exID = EX+convertToMetaNumber(exID); // make it a proper EX metadata number
                
        // now get the EX datastream for that for number
        String exXML = this.getItem(docPID, exID);
        return exXML;
    }

    /** Given a documentNode element, adds the nodetype attribute to all of its
     * docNode descendants. The nodetype is either Root, Internal or Leaf to indicate
     * whether the docnode is a toplevel document Node, or has children or has none.
     * @param e - the documentNode element whose descendants' nodetypes will be set
     * at method's end. */
    protected void addNodeTypeToDescendants(Element e) {
    NodeList sections = e.getElementsByTagName(SECTION_ELEMENT);
    for(int i = 0; i < sections.getLength(); i++) {
        Element section = (Element)sections.item(i);
        NodeList descendants = section.getElementsByTagName(SECTION_ELEMENT);
        if(descendants.getLength() > 0) { 
        // if there are any descendants (which includes children) that are SECTIONS
        section.setAttribute(GSXML.NODE_TYPE_ATT, GSXML.NODE_TYPE_INTERNAL);
        } else {
        section.setAttribute(GSXML.NODE_TYPE_ATT, GSXML.NODE_TYPE_LEAF);
        }
    }
    }


    /** @return the part of the TOC XML file (which outlines doc structure)  
     * relating to the given section. This includes the section denoted by
     * sectionID as well as all descendent subsections thereof. 
     * @param docPID - a fedora pid identifying a greenstone document object.
     * @param sectionID - identifyies the particular section in the
     * document denoted by docPID, may be a section name or number. 
     * @param structure can contain any combination of: ancestors, parent, 
     * siblings, children, descendants, entire, specifying the portion of 
     * the structure to retrieve.
     * @param info can contain any combination of: siblingPosition, numSiblings, 
     * numChildren, requesting additional information about the structure. */
    public Element getSectionStructureXML(String docPID, String sectionID, String structure, String info)
        throws RemoteException, UnsupportedEncodingException, SAXException, IOException 
    {
    // get the TableOfContents (TOC) XML datastream as a String 
    String xmlTOC = getTOC(docPID);
    
    // convert it into a DOM document
    InputSource source = new InputSource(new StringReader(xmlTOC));
    Document doc = builder.parse(source);
    // toplevel element docEl = <Section id="1"></Section>
    Element docEl = doc.getDocumentElement();
    addNodeTypeToDescendants(docEl);
    docEl.setAttribute(GSXML.NODE_TYPE_ATT, GSXML.NODE_TYPE_ROOT);

    if(structure.indexOf("entire") != -1) { // don't need to find the specific section, doc root is what's required
        docEl = getStructureInfo(docEl.getOwnerDocument(), docEl, info);
        return docEl;
    }

    if(sectionID.equals("")) {
        sectionID = "1";
    }
    
    // Store just the number
    String sectionNumber = removePrefix(sectionID, SECTION);
    // Check whether we're requested to return the toplevel element itself
    // If sectionNumber=1, then the top-level element/document element
    // of the TOC XML is requested, so return the TOC as is.    
    if(sectionNumber.equals("1") && structure.indexOf("descendants") != -1) { 
        docEl = getStructureInfo(docEl.getOwnerDocument(), docEl, info);
        return docEl;       
    }
    
    // if the root is the section required, return that
    if(docEl.getTagName().equals(SECTION_ELEMENT) 
       && docEl.getAttribute(ID).equals(sectionNumber)) {
        Element substructure = getSubstructure(docEl, structure);
        return getStructureInfo(substructure.getOwnerDocument(), docEl, info);
        //return docEl; 
    }
    

    // Else, get all <Section> elements and find the
    // <Section id="sectionNumber"></Section> and return that
    NodeList sections = docEl.getElementsByTagName(SECTION_ELEMENT);
    for(int i = 0; i < sections.getLength(); i++) {
        
        Element e = (Element)sections.item(i);
        if(e.hasAttribute(ID) && e.getAttribute(ID).equals(sectionNumber)) {
        Element substructure = getSubstructure(e, structure);
        return getStructureInfo(substructure.getOwnerDocument(), e, info);
        }
    }

    return null; // not found
    }

    
    /** Implements browsing document titles of a greenstone collection stored in 
     * the fedora repository by letter. 
     * @return the document pids whose titles start with the given letter.
     * @param collName - the name of the collection.
     * @param letter - the starting letter to browse by.
     */ 
    public String[] browseTitlesByLetter(final String collName, final String letter) 
        throws RemoteException, FedoraVersionNotSupportedException
    {
        String[] pids = null;
         
        // We want to do the following kind of search (assuming letter=f 
        // and collName=demo): 
        // pid~greenstone:demo* title~f*
        
        // We don't need to normalise the letter first (to search titles starting 
        // with both uppercase and lowercase versions of the letter), because  
        // Fedora always searches for both. 
        // HOWEVER, searching for title~f* returns all documents containing f (or F)  
        // ANYWHERE in their titles!
        // SOLUTION: search the collection for all titles containing f as given,
        // retrieving pid and title fields. Then from the list of results, select
        // only those titles that start with the given letter.
        // This may seem an unnecessarily cumbersome job (when it looked like it 
        // should have worked with just title~f*), BUT, at least the resulting 
        // documents will be reduced to a set of titles containing f; rather than
        // having to search *all* documents in the collection.
        final String title = letter+WILDCARD;
        
        FieldSearchResult objects = findObjectsWithTitlesContaining(
                collName, title);
        ObjectFields[] results = objects.getResultList();
        TreeSet v = new TreeSet(); // TreeSet to return the results in 
                                //alphabetical order
        for(int i = 0; i < results.length; i++) {
            // from the result list, select those titles that don't
            // just *contain* the letter, but actually start with it:
            String resultTitle = results[i].getTitle(0);
            if(resultTitle.toLowerCase().startsWith(letter.toLowerCase())) {
                String pid = results[i].getPid();
                // skip the collection object itself
                if(!pid.equalsIgnoreCase(GREENSTONE_+collName+_COLLECTION)) {
                    v.add(pid);
                    //LOG.debug(resultTitle);
                }
            }
        }
        pids = new String[v.size()];
        v.toArray(pids);
        return pids;
    }
        
    /** Implements querying document DC titles of a greenstone collection stored in 
     * the fedora repository for a term that may occur anywhere in their titles. 
     * @return the document pids whose DC titles contain the parameter term.
     * @param titleContents - the word or phrase to search the collection's 
     * document titles for. Only one word, and this method finds Greenstone 
     * DOCUMENT titles CONTAINING that word (if any). 
     * @param startsWith - if true, searches for titles that start with 
     * titleContents. Else it searches for titles that contain titleContents. */
    public String[] searchDocumentTitles(String collName, String titleContents,
            boolean startsWith) 
        throws RemoteException, FedoraVersionNotSupportedException 
    {
        String[] pids = null;
         
        // We want to do the following kind of search (when written in Fedora's 
        // REST format - see http://localhost:8080/fedora/search): 
        // pid~greenstone:<colname>-* title~<1st word of titleContents>
        
        // We don't need to normalise the word first (to search titles starting 
        // with both uppercase and lowercase versions of it), because  
        // Fedora always searches for the normalised word. 
        
        // 2 difficulties:
        // - We can only search for single words with Fedora's Conditional Search.
        // Obtain pids and titles of documents containing the first word and then  
        // we filter the titles to those containing the entire phrase of 
        // titleContents.
        // - Searching for title~FirstWord returns all documents containing  
        // this word ANYWHERE in their titles. If parameter startsWith is false,
        // then this is fine. But if parameter startsWith is true, then go  
        // through all the resulting titles found (containing FirstWord), select
        // only pids of those titles that contain the entire phrase titleContents
        
        final String pid = GREENSTONE_+collName+HYPHEN+WILDCARD; 
        
        int indexOfFirstSpace = titleContents.indexOf(' '); // check for space
        // if titleContents is a phrase (contains space), then it's not  
        // a single word, in which case search for just the first word
        String title = titleContents; // assume it's a single word
        if(indexOfFirstSpace != -1) // if not single word but a phrase, store
            title = titleContents.substring(0, indexOfFirstSpace); // 1st word
    
        FieldSearchResult objects = findObjectsWithTitlesContaining(
                collName, title);
        if(objects == null) {
            final String[] empty = {};
            return empty;
        }
        
        // Go through all the titles found and for those that match the criteria*,
        // store their pid. *Criteria: titles that start with OR contain the 
        // word OR phrase of titleContents.
        ObjectFields[] results = objects.getResultList();
        Vector v = new Vector(); // return pids in the order found
        for(int i = 0; i < results.length; i++) {
            // from the result list, select those titles that don't
            // just *contain* the first word, but the entire phrase of
            // words in titleContents:
            String resultTitle = results[i].getTitle(0);
            boolean accepted = false; // accept the resultTitle found
            
            String resultPID = results[i].getPid();
            // skip the collection object itself, since it's not a document
            if(resultPID.equalsIgnoreCase(GREENSTONE_+collName+_COLLECTION)) {
                accepted = false;
            }
            // if titleContents is a single word and we are checking 
            // whether resultTitle contains titleContents:
            else if(indexOfFirstSpace == -1) { // titleContents is a single word
                if(!startsWith) // titles that *contain* the word titleContents
                    accepted = true; //accept all titles found
                // else startWith: accept titles starting with word titleContents
                else if (resultTitle.toLowerCase().startsWith(
                            titleContents.toLowerCase()))
                    accepted = true;
                
            } 
            else { // otherwise, titleContents is a phrase of >1 word, need 
                // to check that the result title contains the entire phrase
                if(startsWith && resultTitle.toLowerCase().startsWith(
                        titleContents.toLowerCase()))
                    accepted = true;
                else if(!startsWith && resultTitle.toLowerCase().contains(
                        titleContents.toLowerCase()))
                    accepted = true;
            }
            
            // if the resultTitle fit the criteria, store its pid
            if(accepted) {
                v.add(resultPID);
                //System.out.println(resultTitle);
            }
            
        }
        pids = new String[v.size()];
        v.toArray(pids);
        return pids;
    } 


    /** 
     * @param collName - the collection of documents we'll be searching in.
     * @param titleWord - the word we'll be searching the document titles for.
     * (Fedora's search returns all objects whose title contains that word). 
     * 
     * Two kinds of search are provided by Fedora as stated in FedoraAccess.java
     * (see link):
     * <pre>
     * "There are two search methods: a search on all fields or a search on
     * specific fields. To search all fields the setTerms function of the 
     * FieldSearchQuery must be used, with the paramater being the desired string.
     * 
     * To search by specific fields, you must create an array of Condition
     * objects. Each condition consists of three parts: 
     * the field to be searched (.setProperty()), 
     * the operation to be used (.setOperator(ComparisonOperator. &lt;operator&gt;)), 
     * and the search string (.setValue())"
     * </pre>
     * We want to use the second search method above when browsing and searching, 
     * and search for: pid~greenstone:&lt;collName&gt;* title~&lt;letter&gt;*
     * or pid~greenstone:&lt;collName&gt;* title~&lt;first word of search phrase&gt;
     * See also fedora-2.2.1-src/src/java/fedora/client/search/Search.java.
     * 
     * The fedora/tomcat/webapps/fedora/WEB-INF/web.xml is where the REST-based 
     * web services are defined. (The web.xml defines the "Servlets for REST-based
     * interfaces to the Fedora Repository Server"). 
     * Do a search on the word "search":
     * fedora.server.access.FieldSearchServlet is the class we need to look at
     * It accesses a different Condition.java class: fedora.server.search.Condition.java
     * The above is what is used by the REST-based interface in FieldSearchServlet.java
     * While fedora-2.2.1-src/build/wsdl/fedora/server/types/gen/Condition.java
     * is what's used in the fedora client application that makes use of
     * the SOAP-based interface.
     * 
     * @see <a href="http://drc-dev.ohiolink.edu/browser/elated-core/tags/upstream/src/org/acs/elated/fed/FedoraAccess.java?rev=76&format=txt">FedoraAccess.java</a>
     * @see <a href="http://drc-dev.ohiolink.edu/browser/elated-core/trunk/WEB-INF/src/org/acs/elated/fed/MaAPI.java?rev=275">MaAPI</a>
     * @see <a href="http://www.fedora.info/download/2.2.1/javadocs/fedora/server/types/gen/Condition.html">Fedora server type Condition.java</a>
     * @see <a href="http://source.uhi.ac.uk/fisheye/browse/svn/ctrep/trunk/fedora-ws-clients/testapp/testsrc/fedora/webservices/client/api/a/test/Search.java?r1=133&r2=165">Fedora client test Search.java</a>
     */
    protected FieldSearchResult findObjectsWithTitlesContaining(
            String collName, final String titleWord) 
        throws RemoteException, FedoraVersionNotSupportedException
    {
        // Searching for pids of the form "greenstone:gs2mgdemo-*";
        final String pid = GREENSTONE_+collName+HYPHEN+WILDCARD;
        
        Condition[] conditions = new Condition[2];
        conditions[0] = new Condition("pid", ComparisonOperator.has, pid);
        conditions[1] = new Condition("title", ComparisonOperator.has, titleWord);  
        
        FieldSearchQuery query = new FieldSearchQuery();
        query.setConditions(conditions);
        
        // We'd like pid and title returned for each object, because we'll make
        // use of title. We pass maxResults=null to get all objects that match
        // (i.e. all collections).
        FieldSearchResult objects = null;
        final String[] retrieveFields = {"pid", "title"};
        try {
            objects = AutoFinder.findObjects(
                    APIA, retrieveFields, maxresults, query);
            // collection = APIA.findObjects(new String[]{"pid", "title"}, 
                // new NonNegativeInteger(Integer.toString(maxresults)), query);
        } catch(RemoteException ex) {
            if(fedoraVersion.compareTo(SUPPORTED_VERSION) < 0) { 
                // fedoraVersion is too low, searching/browsing is not possible
                // (because class Condition has changed after 2.0, from 2.1.1 
                // onwards)
                throw new FedoraVersionNotSupportedException(fedoraVersion);
            } else { 
                LOG.error(
                    "Remote exception when calling web service operation " +
                    "findObject() to execute search:\n" + ex.getMessage());
                ex.printStackTrace();
                throw ex;
            }
        }
        return objects; // return the FieldSearchResult objects found
    } 
    
    /** @return the &lt;docName&gt; in the parameter docPID (which is of the form: 
     *  greenstone:&lt;colname&gt;-&lt;docName&gt;) 
     *  @param docPID - pid of a greenstone document in the fedora repository. */
    public String getDocName(String docPID) {
        return docPID.substring(docPID.indexOf('-')+1);
    }
    
    /** @return the &lt;name&gt; in the parameter collPID 
     * (greenstone:&lt;name&gt;-collection) 
     * If collPID is a docPID, this method does the same: return the &lt;name&gt; 
     * in the docPID (greenstone:&lt;name&gt;-docID). 
     * @param collPID - pid of a greenstone collection in the fedora repository. */
    public String getCollectionName(String collPID) {
        return collPID.substring(collPID.indexOf(':')+1, collPID.indexOf('-'));
    }
    
    
    /** Return the TOC substructure requested
     * @return an element containing a copy if element e with either only its child
     * elements or with all its descendants and/or its ancestors or only its parent 
     * and/or its siblings (depending on what the parameter structure specifies).
     * @param e - the element to start copying from and whose structure is requested.
     * @param structure - a string containing any combination of the values:
     * ancestors, parent, siblings, children, descendants,
     * specifying the portion of the structure to retrieve.
     * @see <a href="http://forum.java.sun.com/thread.jspa?threadID=678472&tstart=30">Sun java thread on transforming a DOM XML to a String</a>
     */
    protected Element getSubstructure(Element original, String structure) 
    {
    Document doc = builder.newDocument();
    
    boolean descendants = (structure.indexOf("descendants") != -1) ? true : false;
    Node current = doc.importNode(original, descendants);

    // descendants=true: import/copy descendants.
    // Else, copy just current node original (later copy its direct children)   
    
    Node parentOfCurrent = null;
    Node parentOfOriginal = original.getParentNode();
    if(parentOfOriginal == original.getOwnerDocument()) { // don't want document node (original is docRoot)
        parentOfOriginal = null;
    }
    
    if(parentOfOriginal == null) { // no parentNode, so current is the root node.
        // can't get ancestors/parent/siblings, since all these need parentNode
        doc.appendChild(current);
    } else { // siblings, ancestors and parent requests all require parent node to exist
        // First check if we need to get ancestors, else for whether parent is required
        if(structure.indexOf("ancestors") != -1) {
        parentOfCurrent = doc.importNode(parentOfOriginal, false);
        
        Node child = null;
        Node parent = parentOfCurrent;      // the copy
        Node n = parentOfOriginal.getParentNode(); // the doc to copy from
        
        while(n != null && n != original.getOwnerDocument()) {
            child = parent;
            parent = doc.importNode(n, false); // no descendants
            parent.appendChild(child);
            n = n.getParentNode();
        }
        
        doc.appendChild(parent); // need to put the copied node into a document
        // else it won't have a parent doc (DOMSource can't work with it
        // without it having a document parent).
        
        } else if(structure.indexOf("parent") != -1) {
        parentOfCurrent = doc.importNode(parentOfOriginal, false);
        //parentOfCurrent.appendChild(current);
        doc.appendChild(parentOfCurrent);
        }
        
        // a request for siblings is independently tested for
        if(structure.indexOf("siblings") != -1) {
        // only import parent if we didn't already import
        // it for a request for ancestors or parent
        if(parentOfCurrent == null) { 
            parentOfCurrent = doc.importNode(parentOfOriginal, false);
            doc.appendChild(parentOfCurrent);     // this becomes the root
        }
        // now the siblings of current (children of parentOfCurrent)
        NodeList children = parentOfOriginal.getChildNodes();           
        for(int i = 0; i < children.getLength(); i++) {
            Node n = children.item(i);

            if(n.getNodeName().equals(SECTION_ELEMENT)) { 
            if((Element)n != original) { // skip original which was already imported
                Node child = doc.importNode(n, false); // no descendants
                parentOfCurrent.appendChild(child);
            } else { // already imported Current element, insert at this position               
                parentOfCurrent.appendChild(current);
            }
            
            }           
        }
        } else if(parentOfCurrent != null) { // include current node for ancestors and parent requests
        // (sibling request adds the current node into a particular position) 
        parentOfCurrent.appendChild(current);
             // need to put the copied node into a document
             // else it won't have a parent doc (DOMSource can't work with it
             // without it having a document parent).
        } else { // when only children or descendants were requested, current becomes root document
        doc.appendChild(current);
        }
    }

    // if we are not recursively copying all descendants, then copy just 
    // the childnodes of current:
    if(structure.indexOf("children") != -1 && !descendants) { // then copy just the children

        // get e's children and copy them into the new document
        NodeList children = original.getChildNodes();
        for(int i = 0; i < children.getLength(); i++) {
        // create copy
        Node n = doc.importNode(children.item(i), false);
        // attach it to parent
        current.appendChild(n);
        
        // Now we need to indicate whether this new node (child) is a leaf
        // or not. (This is necessary for getChildrenOfSection(), else 
        // it's hard to know if the children are leaves or have further 
        // subsections.
        if(n.getNodeName().equals(SECTION_ELEMENT)) {
            // we're dealing only with section children
            
            // Check if the matching original had children:
            Element originalsChild = (Element)children.item(i);
            NodeList grandchildren = originalsChild.getElementsByTagName(SECTION_ELEMENT);
            if(grandchildren.getLength() > 0) {
            // original's child has children, so indicate this
            // in the copied child:
            Element child = (Element)current;           
            //  child.setAttribute(TYPE, INTERNAL_NODE);
            
            }
        }
        }
    }

    return doc.getDocumentElement();
    }    


    /** Return the TOC substructure with the requested structural info.
     * @return an element containing a copy if element e with either only its child
     * elements or with all its descendants and/or its ancestors or only its parent 
     * and/or its siblings (depending on what the parameter structure specifies).
     * Returns null if the element, e, passed in is null.
     * @param doc - the new document into whose root element the structural information
     * will be inserted as attributes.
     * @param e - the element to start copying from and whose structure is requested.
     * @param info - a string containing any combination of the values: numChildren, 
     * numSiblings, siblingPosition. The requested info gets added as attributes to
     * the returned root element.
     * @see <a href="http://forum.java.sun.com/thread.jspa?threadID=678472&tstart=30">Sun java thread on transforming a DOM XML to a String</a>
     */
    protected Element getStructureInfo(Document doc, Element e, String info) 
    {
    if(e == null) {
        return null;
    }
    
    Element root = doc.getDocumentElement();

    if(!info.equals("")) {   
        if(info.indexOf("numChildren") != -1) {
        //int numChildren = e.getElementsByTagName(SECTION_ELEMENT).getLength();
        int numChildren = 0;
        
        NodeList children = e.getChildNodes();
        for(int i = 0; i < children.getLength(); i++) {
            Node n = children.item(i); 
            if(n.getNodeName().equals(SECTION_ELEMENT)) {
            numChildren++;
            }
        }
        
        root.setAttribute("numChildren", Integer.toString(numChildren));
        }
        
        if(info.indexOf("ibling") != -1) { // siblingPosition or numSiblings
        int numSiblings = 0;
        int siblingPosition = 0;
            
        Node parent = e.getParentNode();
        if(parent == null) {
            numSiblings = 0;
            siblingPosition = 1;
        } else {
            //numSiblings = parent.getChildNodes().getLength();
            NodeList siblings = parent.getChildNodes();
            
            for(int i = 0; i < siblings.getLength(); i++) {
            Node n = siblings.item(i); 
            if(n.getNodeName().equals(SECTION_ELEMENT)) {
                if(e == (Element)n) {
                siblingPosition = numSiblings+1;
                } else { // count every sibling section element, except e itself
                numSiblings++;
                }               
            }
            }
        }       
        
        if(info.indexOf("numSiblings") != -1) {
            root.setAttribute("numSiblings", Integer.toString(numSiblings));
        }
        
        if(info.indexOf("siblingPosition") != -1) {
            root.setAttribute("siblingPosition", Integer.toString(siblingPosition));
        }
        }
    }
    
    return root;
    }


    /** 
     * Return a datastream of a document, given the document's id
     * and the item id of the datastream which is to be retrieved.
     * @return the XML (in String form) of the item denoted by itemID  
     * that's part of the fedora data object denoted by docPID. 
     * itemID may be something like EX.2.1/EX2.3.3 or SECTION1.4.3
     * Can't retrieve images denoted by itemID using this method, only items
     * that are of XML format.
     * @param docPID - pid of a greenstone document in the fedora repository.
     * @param itemID - the itemID of a datastream of the fedora object 
     * identified by docPID.
    */
    protected String getItem(String docPID, String itemID)  
        throws RemoteException, UnsupportedEncodingException
    {
        // MIMETypedStream getDatastreamDissemination(
            // String pid, String dsID, asOfDateTime) 
        MIMETypedStream datastream 
            = APIA.getDatastreamDissemination(docPID, itemID, null);
        return new String(datastream.getStream(), UTF8);
    }
    
    /** Given something like str="SECTION1.2.1" and prefix="SECTION" this method 
     * returns "1.2.1". 
     * The exception is that for cases like EX.2.1, which ought to have been EX1.2.1, 
     * this method would return "1.2.1". Similarly, DC.2.1 would return "1.2.1".
     * However, the string str is returned unchanged if the prefix does not occur
     * at the start of str. 
     * @return the String parameter str without the prefix.
     * It can be used to return the number of an itemID of a greenstone document 
     * stored in the fedora repository without the given prefix.  
     * @param prefix - the prefix which ought to be removed from the itemID.
     * @param str - the value of the itemID.
    */
    protected String removePrefix(String str, String prefix) {
        // do nothing in those cases where the prefix is not in param str
        if(!str.startsWith(prefix)) 
            return str;
        // otherwise:
        if(prefix.equals(EX+".") || prefix.equals(DC+".")) {
            return "1" + str.substring(prefix.length());    
        } else {
            return str.substring(prefix.length());
        }
    }
        
    /** Given a number of the form x(.y.z), this method returns this number
     * as is, except when x = 1, in which case, it would return .y.z 
     * That is, given number=3.2.1, this method would return 3.2.1
     * But, given number=1.2.3, this method would return .2.3.
     * When number=1, it is NOT a special case: "" is returned as explained. 
     * @param number - a proper (fedora-greenstone document) section number 
     * @return the same number as it ought to be for the associated EX, DC datastreama. 
    */
    protected String convertToMetaNumber(String number) {
        if(number.startsWith("1.") || number.equals("1"))
            return number.substring(1); // remove the first char: the initial '1'
        else return number;
    }
    
    /** @return fedora's baseURL. It's of the form
     * "http://localhost:8080/fedora" */
    public String getBaseURL() { return baseURL; }
    
    /** @return the portAddressURL (in use) of the Fedora APIA 
     * web service (should be the endpoint location in the APIA's 
     * WSDL file). 
     * It's usually of the form baseURL+"/services/access" */
    public String getPortAddressURL() { 
        return this.baseURL + this.portAddressSuffix; 
    }
    
    /** @return the baseURL for gsdlAssocFiles */
    public String getAssocFileBaseURL() { return baseURL + "/get/"; }
    
    public static void main(String args[]) {
        try {
            FedoraConnection fedoraCon 
                = new FedoraConnection(new File("fedoraGS3.properties"));
            
            String[] pids = null; 
            pids = fedoraCon.getCollections();
            String[] titles = fedoraCon.getCollectionTitles(pids);
            for(int i = 0; i < pids.length; i++) {
                System.out.println("extracted title:" + titles[i]);
                String[] docPIDs = fedoraCon.getCollectionDocs(pids[i]);
                String[] docTitles = fedoraCon.getDocTitles(docPIDs);
                for(int j = 0; j < docPIDs.length; j++) { 
                    System.out.println("\tExtr doc title: " + docTitles[j]);
                }
            }   
            
            String PID = "greenstone:gs2mgdemo-collection";
            String docPID = "greenstone:gs2mgdemo-HASH529078c732a453b1d4a505"; //HASHbf4b4675045599fbc3e2b1";
            String dcXML = fedoraCon.getDC(PID);
            String exXML = fedoraCon.getEX(PID);
            String tocXML = fedoraCon.getTOC(docPID);
            System.out.println("Dublin Core Metadata for " + PID 
                    + " is:\n" + dcXML);
            System.out.println("GS3 extracted metadata for " + PID 
                    + " is:\n" + exXML);
            System.out.println("Table of Contents for " + docPID 
                    + " is:\n" + tocXML);
            
            
            String[] sectionNames = fedoraCon.getSectionNames(docPID);
            System.out.println("\nSection names for " + docPID + " are:");
            for(int i = 0; i < sectionNames.length; i++)
                System.out.println(sectionNames[i]);
            
            String[] sectionNumbers = fedoraCon.getSectionNumbers(docPID);
            //String[] sectionTitles = fedoraCon.getTitles(docPID, sectionNumbers);
            String[] sectionTitles = fedoraCon.getTitles(docPID, sectionNames);
            System.out.println("\nSection numbers for " + docPID + " are:");
            for(int i = 0; i < sectionNumbers.length; i++) {
                //System.out.println(sectionNumbers[i] + " " + sectionTitles[i]);
                System.out.println(sectionNames[i] + " " + sectionTitles[i]);
            }
            
            String sectionID = "SECTION1"; //SECTION1.5
            System.out.println("\n");
                    
            System.out.println(
                "browsing greenstone's gs2mgdemo collection by (first) letter F:");
            pids = fedoraCon.browseTitlesByLetter("gs2mgdemo", "f");
            for(int i = 0; i < pids.length; i++)
                System.out.println(pids[i]);
            
            System.out.println(
                "\nsearching greenstone's gs2mgppdemo collection for Gender Equality:");
            pids = fedoraCon.searchDocumentTitles("gs2mgdemo", "Gender Equality", false);
            for(int i = 0; i < pids.length; i++)
                System.out.println(pids[i]);
            
            System.out.println("\nDone - exiting.");
            System.exit(0);
        } catch(RemoteException re) {
            System.out.println("Remote Exception when calling web service operation\n" + re.getMessage());
            re.printStackTrace();
        } catch(Exception e) {
            System.out.println("Unable to instantiate FedoraConnection\n" + e);
            e.printStackTrace();
            //LOG.error("Unable to instantiate FedoraConnection\n" + e, e);
        }
    }
}