source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/core/Receptionist.java@ 25090

package org.greenstone.gsdl3.core;

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

// other java classes
import java.io.File;
import java.util.HashMap;
import java.util.Enumeration;
import java.util.ArrayList;

import org.apache.log4j.*;

/**
 * the most basic Receptionist, used for interface generation. Receives requests
 * consisting of an xml representation of cgi args, and returns the page of
 * data. The requests are processed by the appropriate action class
 * 
 * @see Action
 */
public class Receptionist implements ModuleInterface
{

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.core.Receptionist.class.getName());

    /** the 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;

    /** the message router that the Receptionist and Actions will talk to */
    protected ModuleInterface mr = null;

    /** the list of actions */
    protected HashMap action_map = null;

    /** the list of params */
    protected GSParams params = null;
    protected Element language_list = null;

    /** the list of interfaces this is based on */
    protected ArrayList base_interfaces = null;

    public Receptionist()
    {
        this.converter = new XMLConverter();
        this.doc = this.converter.newDOM();
        this.action_map = new HashMap();
    }

    public void cleanUp()
    {
    }

    public void setParams(GSParams params)
    {
        this.params = params;
    }

    public void setConfigParams(HashMap params)
    {
        this.config_params = params;
    }

    public HashMap getConfigParams()
    {
        return this.config_params;
    }

    /**
     * sets the message router - it should already be created and configured
     * before being passed to the receptionist
     */
    public void setMessageRouter(ModuleInterface m)
    {
        this.mr = m;
    }

    /** configures the receptionist */
    public boolean configure()
    {

        if (this.config_params == null)
        {
            logger.error(" config variables must be set before calling configure");
            return false;
        }
        if (this.mr == null)
        {
            logger.error(" message router must be set  before calling configure");
            return false;
        }

        // find the config file containing a list of actions
        File interface_config_file = new File(GSFile.interfaceConfigFile(GSFile.interfaceHome(GlobalProperties.getGSDL3Home(), (String) this.config_params.get(GSConstants.INTERFACE_NAME))));
        if (!interface_config_file.exists())
        {
            logger.error(" interface config file: " + interface_config_file.getPath() + " not found!");
            return false;
        }

        Document config_doc = this.converter.getDOM(interface_config_file);
        if (config_doc == null)
        {
            logger.error(" could not parse interface config file: " + interface_config_file.getPath());
            return false;
        }
        Element config_elem = config_doc.getDocumentElement();
        String base_interface = config_elem.getAttribute("baseInterface");
        setUpBaseInterface(base_interface);
        setUpInterfaceOptions(config_elem);

        // load up the actions
        Element action_list = (Element) GSXML.getChildByTagName(config_elem, GSXML.ACTION_ELEM + GSXML.LIST_MODIFIER);
        NodeList actions = action_list.getElementsByTagName(GSXML.ACTION_ELEM);

        for (int i = 0; i < actions.getLength(); i++)
        {
            Element action = (Element) actions.item(i);
            String class_name = action.getAttribute("class");
            String action_name = action.getAttribute("name");
            Action ac = null;
            try
            {
                ac = (Action) Class.forName("org.greenstone.gsdl3.action." + class_name).newInstance();
            }
            catch (Exception e)
            {
                logger.error(" couldn't load in action " + class_name);
                e.printStackTrace();
                continue;
            }
            ac.setConfigParams(this.config_params);
            ac.setMessageRouter(this.mr);
            ac.configure();
            ac.getActionParameters(this.params);
            this.action_map.put(action_name, ac);
        }

        this.language_list = (Element) GSXML.getChildByTagName(config_elem, "languageList");
        if (language_list == null)
        {
            logger.error(" didn't find a language list in the config file!!");
        }

        return true;
    }

    public String process(String xml_in)
    {

        Node message_node = this.converter.getDOM(xml_in);
        Node page = process(message_node);
        return this.converter.getString(page);
    }

    /**
     * process - produce a page of data in response to a request if something
     * goes wrong, it returns null - TODO: return a suitable message to the user
     */
    public Node process(Node message_node)
    {

        Element message = this.converter.nodeToElement(message_node);

        // get the request out of the message - assume that there is only one
        Element request = (Element) GSXML.getChildByTagName(message, GSXML.REQUEST_ELEM);
        if (request == null)
        {
            logger.error(" message had no request!");
            return null;
        }
        // check the request type 
        String type = request.getAttribute(GSXML.TYPE_ATT); // returns "" if no att of this name
        if (!type.equals(GSXML.REQUEST_TYPE_PAGE))
        {
            // now Receptionist forwards non-page requests straight to the MR, and returns the responses
            logger.error(" request type is not '" + GSXML.REQUEST_TYPE_PAGE + "', but it is '" + type + "', so forwarding the message to the MR!");
            // process the whole message - mr needs <message> tags, and 
            // in this case, there may be more than one request in the message
            return this.mr.process(message);
        }
        // work out which action to pass to
        String action = request.getAttribute(GSXML.ACTION_ATT);
        if (action.equals(""))
        {
            logger.error(" no action specified in the request!");
            return null;
        }

        // find the  appropriate action 
        Action a = (Action) this.action_map.get(action);

        String action_name = null;
        if (a == null)
        { // not in the map yet
            // try to load a new action
            try
            {
                action_name = action.substring(0, 1).toUpperCase() + action.substring(1) + "Action";
                Action ac = (Action) Class.forName("org.greenstone.gsdl3.action." + action_name).newInstance();
                ac.setConfigParams(this.config_params);
                ac.setMessageRouter(this.mr);
                ac.configure();
                ac.getActionParameters(this.params);
                this.action_map.put(action, ac);
                a = ac;
            }
            catch (Exception e)
            {

                logger.error(" a new action (" + action_name + ") was specified and it couldn't be created. Error message:" + e.getMessage());
                return null;
            }
        }

        // transform the request in some way -- does nothing!
        preProcessRequest(request);
        // set up the page
        Element page = this.doc.createElement(GSXML.PAGE_ELEM);
        page.setAttribute(GSXML.LANG_ATT, request.getAttribute(GSXML.LANG_ATT));
        // just in case these namespaces end up in the page and we want to display the XML
        page.setAttribute("xmlns:gsf", "http://www.greenstone.org/greenstone3/schema/ConfigFormat");
        page.setAttribute("xmlns:xsl", "http://www.w3.org/1999/XSL/Transform");

        //logger.info(a+" mesa=" + this.converter.getPrettyString(message));
        // get the page data from the action
        Node action_response = a.process(message);

        boolean response_only = false;
        Element param_list = (Element) GSXML.getChildByTagName(request, GSXML.PARAM_ELEM + GSXML.LIST_MODIFIER);
        if (param_list != null)
        {
            Element param = GSXML.getNamedElement(param_list, GSXML.PARAM_ELEM, GSXML.NAME_ATT, "ro");
            if (param != null)
            {
                String value = param.getAttribute("value");
                if (value.equals("1"))
                {
                    response_only = true;
                }
            }
        }
        if (response_only)
        {
            // only the response from the action is sent back
            return action_response;
        }

        // the request is part of the page
        page.appendChild(GSXML.duplicateWithNewName(this.doc, request, GSXML.PAGE_REQUEST_ELEM, true));
        // add the response too
        Element page_response = GSXML.duplicateWithNewName(this.doc, (Element) GSXML.getChildByTagName(action_response, GSXML.RESPONSE_ELEM), GSXML.PAGE_RESPONSE_ELEM, true);
        page.appendChild(page_response);

        //logger.info(" raw page="+this.converter.getString(page));
        // transform the result in some way
        //Element resulting_page = postProcessPage(page);

        Node resulting_page = postProcessPage(page);

        logger.debug("receptionist returned response");
        //logger.error("receptionist returned response");
        logger.debug(this.converter.getString(resulting_page));
        //logger.error(this.converter.getString(resulting_page));
        //    logger.info("receptionist returned response");
        //    logger.info(this.converter.getString(resulting_page));

        return resulting_page;

    }

    protected boolean setUpBaseInterface(String base_interface)
    {
        if (base_interface == null || base_interface.equals(""))
        {
            // there was no base interface, the list remains null
            return true;
        }
        // foreach base interface
        while (!base_interface.equals(""))
        {
            // find the base interface config file
            File base_interface_config_file = new File(GSFile.interfaceConfigFile(GSFile.interfaceHome(GlobalProperties.getGSDL3Home(), base_interface)));
            if (!base_interface_config_file.exists())
            {
                logger.error(" base interface config file: " + base_interface_config_file.getPath() + " not found!");
                return false;
            }
            // the interface name is valid, add it to the list
            if (base_interfaces == null)
            {
                base_interfaces = new ArrayList();
            }
            base_interfaces.add(base_interface);
            // now see if this has a base interface
            Document config_doc = this.converter.getDOM(base_interface_config_file);
            if (config_doc == null)
            {
                logger.error(" could not parse base interface config file: " + base_interface_config_file.getPath());
                return false;
            }
            Element config_elem = config_doc.getDocumentElement();
            base_interface = config_elem.getAttribute("baseInterface");
        }
        return true;
    }

    protected boolean setUpInterfaceOptions(Element config_elem)
    {
        Element option_list = (Element) GSXML.getChildByTagName(config_elem, "optionList");
        if (option_list != null)
        {
            logger.debug("found an interface optionList");
            // we set any options in the config params
            NodeList options = option_list.getElementsByTagName("option");
            for (int i = 0; i < options.getLength(); i++)
            {
                Element option = (Element) options.item(i);
                String name = option.getAttribute(GSXML.NAME_ATT);
                String value = option.getAttribute(GSXML.VALUE_ATT);
                logger.debug("option: " + name + ", " + value);
                if (!name.equals("") && !value.equals(""))
                {
                    this.config_params.put(name, value);
                }
            }
        }

        return true;
    }

    protected void preProcessRequest(Element request)
    {
        return;
    }

    protected Node postProcessPage(Element page)
    {
        return page;
    }

}