OAIQualifiedDCCrosswalk.java

/*
 * OAIDCCrosswalk.java
 *
 * Version: $Revision: 3705 $
 *
 * Date: $Date: 2009-04-11 18:02:24 +0100 (Sat, 11 Apr 2009) $
 *
 * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
 * Institute of Technology.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Hewlett-Packard Company nor the name of the
 * Massachusetts Institute of Technology nor the names of their
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
package org.dspace.app.oai;

import java.util.Properties;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.dspace.content.DCValue;
import org.dspace.content.Item;
import org.dspace.search.HarvestedItemInfo;

import ORG.oclc.oai.server.crosswalk.Crosswalk;
import ORG.oclc.oai.server.verb.CannotDisseminateFormatException;

/**
 * An OAICat Crosswalk implementation that extracts Qualified Dublin Core from
 * DSpace items into the oai_dc format.
 * 
 * @author Robert Tansley
 * 
 * 
 * @author cgormle1  
 * Based this class on OAIDCCrosswalk and made changes to output qualified dc
 * @version $Revision: 3705 $
 */
public class OAIQualifiedDCCrosswalk extends Crosswalk
{
	// Pattern containing all the characters we want to filter out / replace
	// converting a String to xml
	private static final Pattern invalidXmlPattern =
		Pattern.compile("([^\\t\\n\\r\\u0020-\\ud7ff\\ue000-\\ufffd\\u10000-\\u10ffff]+|[&<>])");
    
    // Pattern to test for only true dc elements.
    private static final Pattern dcElementPattern = Pattern
            .compile("(^(title|creator|subject|description|"
                    + "publisher|contributor|date|type|"
                    + "format|identifier|source|language|"
                    + "relation|coverage|rights)$)");
	
    public OAIQualifiedDCCrosswalk(Properties properties)
    {
        super("http://www.openarchives.org/OAI/2.0/oai_dc/ "
                + "http://www.openarchives.org/OAI/2.0/oai_dc.xsd");
    }

    public boolean isAvailableFor(Object nativeItem)
    {
        // We have DC for everything
        return true;
    }

    public String createMetadata(Object nativeItem)
            throws CannotDisseminateFormatException
    {
        Item item = ((HarvestedItemInfo) nativeItem).item;

        // Get all the DC
        DCValue[] allDC = item.getDC(Item.ANY, Item.ANY, Item.ANY);

        StringBuffer metadata = new StringBuffer();

        metadata
                .append(
                        "<oai_dc:dc xmlns:oai_dc=\"http://www.openarchives.org/OAI/2.0/oai_dc/\" ")
                .append("xmlns:dc=\"http://purl.org/dc/elements/1.1/\" ")
                .append(
                        "xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" ")
                .append(
                        "xsi:schemaLocation=\"http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd\">");

        for (int i = 0; i < allDC.length; i++)
        {
            String element = allDC[i].element;
            String qualifier = allDC[i].qualifier;

            // Do not include description.provenance
            boolean provenance = "description".equals(element)
                    && "provenance".equals(qualifier);


            if (!provenance) {

				// contributor.author exposed as 'creator'
				if ("contributor".equals(element) && "author".equals(qualifier)) {
					element = "creator";
				}

				String value = allDC[i].value;

				// Escape XML chars <, > and &
				// Also replace all invalid characters with ' '
				if (value != null) {
					StringBuffer valueBuf = new StringBuffer(value.length());
					Matcher xmlMatcher = invalidXmlPattern.matcher(value.trim());
					while (xmlMatcher.find()) {
						String group = xmlMatcher.group();

						// group will either contain a character that we need to encode for xml
						// (ie. <, > or &), or it will be an invalid character
						// test the contents and replace appropriately

						if (group.equals("&"))
							xmlMatcher.appendReplacement(valueBuf, "&");
						else if (group.equals("<"))
							xmlMatcher.appendReplacement(valueBuf, "<");
						else if (group.equals(">"))
							xmlMatcher.appendReplacement(valueBuf, ">");
						else
							xmlMatcher.appendReplacement(valueBuf, " ");
					}

					// add bit of the string after the final match
					xmlMatcher.appendTail(valueBuf);

					metadata.append("<dc:").append(element);

					if (qualifier != null) {
						metadata.append(".").append(qualifier);
					}

					metadata.append(">").append(valueBuf.toString()).append("</dc:").append(element);
					if (qualifier != null) {
						metadata.append(".").append(qualifier);
					}
					metadata.append(">");

				}
			}
        }

        metadata.append("</oai_dc:dc>");

        return metadata.toString();
    }
}