source: tags/ant-install-branch-merged-1/gsdl3/src/java/org/greenstone/gsdl3/action/Action.java@ 9873

package org.greenstone.gsdl3.action;

import org.greenstone.gsdl3.core.ModuleInterface;
import org.greenstone.gsdl3.util.*;
// XML classes
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 
import org.w3c.dom.Element; 
import org.w3c.dom.Document; 

// other java stuff
import java.io.File;
import java.util.Vector;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;

/** base class for Actions */
abstract public class Action {

    /** the system set up variables */
    protected HashMap config_params = null;
    /** container Document to create XML Nodes */
    protected Document doc=null; 
    /** a converter class to parse XML and create Docs */
    protected XMLConverter converter=null;
    /** a reference to the message router that it must talk to to
     * get info. it may be a communicator acting as a proxy, but it 
     doesn't care about that */
    protected ModuleInterface mr=null;

    public Action() {
    this.converter = new XMLConverter();
    this.doc = this.converter.newDOM();
    }
    /** the config variables must be set before configure is called */
    public void setConfigParams(HashMap params) {
    this.config_params = params;
    }
    /** sets the message router */
    public void setMessageRouter(ModuleInterface m) {
       this.mr = m;
    }
    public boolean configure() {
    // does nothing yet
    return true;
    }
    
    /** process takes an xml representation of cgi args
     * and returns the page of results - may be in html/xml/other
     * depending on the output att of the request */
    public String process(String xml_in) {
       
    Document message_doc = this.converter.getDOM(xml_in);
    if (message_doc == null) {
        System.err.println("Action.process(String) Error: Couldn't parse request");
        System.err.println(xml_in);
        return null;
    }
    Element result = process(message_doc.getDocumentElement());
    return this.converter.getString(result);
    }
    
    /** the main process method - must be implemented in subclass */
    abstract public Element process(Element xml_in);

    /** tell the param class what its arguments are 
     * if an action has its own arguments, this should add them to the params
     * object - particularly important for args that should not be saved */
    public boolean getActionParameters(GSParams params) {
    return true;
    }

    protected void extractMetadataNames(Element format, HashSet meta_names) {
    //NodeList nodes = format.getElementsByTagNameNS("metadata", "http://www.greenstone.org/configformat");
    NodeList nodes = format.getElementsByTagName("gsf:metadata");
        for (int i=0; i<nodes.getLength(); i++) {
        Element elem = (Element)nodes.item(i);
        StringBuffer metadata = new StringBuffer();
        String all = elem.getAttribute("multiple");
        String name = elem.getAttribute("name");
        String select = elem.getAttribute("select");
        String sep = elem.getAttribute("separator");
        if (all.equals("true")) {
        metadata.append("all");
        metadata.append(GSConstants.META_RELATION_SEP);
        }
        if (!select.equals("")) {
        metadata.append(select);
        metadata.append(GSConstants.META_RELATION_SEP);
        }
        if (!sep.equals("")) {
        metadata.append(GSConstants.META_SEPARATOR_SEP);
        metadata.append(sep);
        metadata.append(GSConstants.META_SEPARATOR_SEP);
        metadata.append(GSConstants.META_RELATION_SEP);
        }

        metadata.append(name);
        meta_names.add(metadata.toString());
    }
        
    }

    protected Element createMetadataParamList(HashSet metadata_names) {
    Element param_list  = this.doc.createElement(GSXML.PARAM_ELEM+GSXML.LIST_MODIFIER);
    
    Element param = null;
    Iterator i = metadata_names.iterator();
    while (i.hasNext()) {
        String name = (String)i.next();
        param = this.doc.createElement(GSXML.PARAM_ELEM);
        param_list.appendChild(param);
        param.setAttribute(GSXML.NAME_ATT, "metadata");
        param.setAttribute(GSXML.VALUE_ATT, name);
    
    }
    return param_list;
    }

    protected boolean processErrorElements(Element message, Element page) {
    NodeList error_nodes = message.getElementsByTagName(GSXML.ERROR_ELEM);
    if (error_nodes.getLength()==0) {
        return false;
    }
    Document owner = page.getOwnerDocument();
    for (int i=0; i<error_nodes.getLength(); i++) {
        page.appendChild(owner.importNode(error_nodes.item(i), true));
    }
    return true;
    }
}