source: main/trunk/gli/src/org/greenstone/gatherer/cdm/Index.java@ 36138

/**
 *#########################################################################
 *
 * A component of the Gatherer application, part of the Greenstone digital
 * library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * Author: John Thompson, Greenstone Digital Library, University of Waikato
 *
 * Copyright (C) 1999 New Zealand Digital Library Project
 *
 * 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.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *########################################################################
 */
package org.greenstone.gatherer.cdm;

import java.util.*;
import org.greenstone.gatherer.DebugStream;
import org.greenstone.gatherer.Gatherer;
import org.greenstone.gatherer.metadata.MetadataElement;
import org.greenstone.gatherer.metadata.MetadataTools;
import org.greenstone.gatherer.util.StaticStrings;
import org.greenstone.gatherer.util.XMLTools;
import org.w3c.dom.*;

/** This class encapsulates a single index. MGPP/Lucene/SOLR
 * Can be subclassed for Sort fields and facet fields
 * @author John Thompson, Greenstone Digital Library, University of Waikato
 * @version 2.3d
 */
public class Index
    implements Comparable, DOMProxyListEntry {

    protected ArrayList sources = null;

    /** The element this index is based upon. */
    protected Element element = null;
    /** The name for our elements */
    protected String element_name = StaticStrings.INDEX_ELEMENT;
    /** The name for the default element */
    protected String default_element_name = StaticStrings.INDEX_DEFAULT_ELEMENT;
    /** The unique, if cryptic, identifier of an index. */
    protected String id = null;

    /** Default constructor, which should only be used during DOMProxyListModel creation. */
    public Index() {
    }

    /** Constructor. */
    public Index(Element element) {
    this.element = element;
    }

    /** Constructor for a newly assigned index. */
    public Index(ArrayList sources) {
    this.sources = sources;
    // Create a new element
    this.element = CollectionConfiguration.createElement(this.element_name);
    // For each source add a content element
    int size = sources.size();
    for(int i = 0; i < size; i++) {
        Element content_element = CollectionConfiguration.createElement(StaticStrings.CONTENT_ELEMENT);
        Object source_object = sources.get(i);
        if (source_object instanceof MetadataElement) {
        // System.err.println("Constructing new Index with MetadataElement source...");
        content_element.setAttribute(StaticStrings.NAME_ATTRIBUTE, ((MetadataElement) source_object).getFullName());
        }
        else {
        // System.err.println("Constructing new Index with String source...");
        content_element.setAttribute(StaticStrings.NAME_ATTRIBUTE, source_object.toString());
        }
        element.appendChild(content_element);
        content_element = null;
    }
    }

    /** Method to compare two indexes.
     * @param object The other index as an <strong>Object</strong>.
     * @return An <i>int</i> which indicates how the indexes compare.
     * @see java.lang.String
     */
    public int compareTo(Object object) {
    if(object == null) {
        return -1;
    }
    String id = getID();
    return id.compareTo(((Index)object).getID());
    }
    
    public DOMProxyListEntry create(Element element) {
    return new Index(element);
    }

    /** Method to test for the equality of two indexes.
     * @param object The other index as an <strong>Object</strong>.
     * @return A <i>boolean</i> which is <i>true</i> if the two indexes are equal, <i>false</i> otherwise.
     */
    public boolean equals(Object object) {
    return (compareTo(object) == 0);
    }
    
    public Element getElement() {
    return element;
    }

    public String getID() {
    if(element == null) {
        id="";
    }
    else if(id == null) {
        StringBuffer id_buffer = new StringBuffer();
        // Write data information. Retrieve each of the content sources and add them in a comma separated list.
        ArrayList sources = getSources();
        int sources_size = sources.size();
        for(int i = 0; i < sources_size; i++) {
        Object source_object = sources.get(i);
        if (source_object instanceof MetadataElement) {
            String full_element_name = ((MetadataElement)source_object).getFullName();
            if(full_element_name.startsWith(StaticStrings.EXTRACTED_NAMESPACE) && full_element_name.indexOf(StaticStrings.NS_SEP, StaticStrings.EXTRACTED_NAMESPACE.length()) == -1) {
               id_buffer.append(full_element_name.substring(StaticStrings.EXTRACTED_NAMESPACE.length()));
            }
            else {
            id_buffer.append(full_element_name);
            }
        }
        else {
            id_buffer.append(source_object.toString());
        }
        id_buffer.append(StaticStrings.COMMA_CHARACTER);
        }
        sources = null;
        if (id_buffer.length()==0) {
        id = "";
        } else {
        id = id_buffer.substring(0, id_buffer.length() - 1);
        }
    }
    return id;
    }


    /** Retrieve the sources of this index.
     * @return the sources as an ArrayList
     */
    public ArrayList getSources() {
    if(sources == null) {
        sources = new ArrayList();
        NodeList content_elements = element.getElementsByTagName(StaticStrings.CONTENT_ELEMENT);
        int content_elements_length = content_elements.getLength();
        for(int i = 0; i < content_elements_length; i++) {
        Element content_element = (Element) content_elements.item(i);
        String metadata_element_name_full = (String) content_element.getAttribute(StaticStrings.NAME_ATTRIBUTE);
        MetadataElement metadata_element = MetadataTools.getMetadataElementWithName(metadata_element_name_full);
        if (metadata_element != null) {
            sources.add(metadata_element);
        }
        else {
            sources.add(metadata_element_name_full);
        }
        }
        content_elements = null;
    }
    return sources;
    }

    public boolean isAssigned() {
    return (element != null && !element.getAttribute(StaticStrings.ASSIGNED_ATTRIBUTE).equals(StaticStrings.FALSE_STR));
    }

    public void setAssigned(boolean assigned) {
    if(element != null) {
        element.setAttribute(StaticStrings.ASSIGNED_ATTRIBUTE, (assigned ? StaticStrings.TRUE_STR : StaticStrings.FALSE_STR));
    }
    }

    public void setElement(Element element) {
    this.element = element;
    this.id = null;
    this.sources = null;
    }

    /** Method to set the sources for this index which can only be used for the default index.
     * @param sources an ArrayList of source names
     */
    public void setSources(ArrayList sources) {
    if(element != null && element.getNodeName().equals(this.default_element_name)) {
        // Erase old sources
        XMLTools.clear(element);
        // For each entry in the sources array add a new content element.
        int size = sources.size();
        for(int i = 0; i < size; i++) {
        Element content_element = element.getOwnerDocument().createElement(StaticStrings.CONTENT_ELEMENT);
        Object source_object = sources.get(i);
        if (source_object instanceof MetadataElement) {
            String name = ((MetadataElement) source_object).getFullName();
            content_element.setAttribute(StaticStrings.NAME_ATTRIBUTE, name);
            name = null;
        }
        else {
            //DebugStream.println("Found String as source: " + source_object.toString());
            content_element.setAttribute(StaticStrings.NAME_ATTRIBUTE, source_object.toString());
        }
        source_object = null;
        element.appendChild(content_element);
        content_element = null;
        }
        this.id = null; // Regenerate ID.
        this.sources = sources;
    }
    else {
        DebugStream.println("Error! Called setSource() of index other than the default.");
    }
    }

    /** Method to turn this object into a string representation ready to be placed in the collection configuration file.
     * @return A <strong>String</strong> containing the information of this class.
     */
    public String toString() {
    StringBuffer text_buffer = new StringBuffer("");
    // Generate language dependant id (include extracted metadata namespace)
    // Write data information. Retrieve each of the content sources and add them in a comma separated list.
    ArrayList sources = getSources();
    int sources_size = sources.size();
    for(int i = 0; i < sources_size; i++) {
        String source_name = (sources.get(i)).toString();
        text_buffer.append(source_name);
        if(i < sources_size - 1) {
        text_buffer.append(StaticStrings.COMMA_CHARACTER);
        }
    }
    sources = null;
    return text_buffer.toString();
    }
}