edu.indiana.lib.twinpeaks.search.PreferredUrlHandler.java Source code

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Here is the source code for edu.indiana.lib.twinpeaks.search.PreferredUrlHandler.java

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/**********************************************************************************
*
 * Copyright (c) 2003, 2004, 2008 The Sakai Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.opensource.org/licenses/ECL-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
*
**********************************************************************************/
package edu.indiana.lib.twinpeaks.search;

import edu.indiana.lib.twinpeaks.util.DomUtils;
import edu.indiana.lib.twinpeaks.util.LogUtils;
import edu.indiana.lib.twinpeaks.util.StringUtils;

import java.util.ArrayList;

import javax.xml.parsers.*;

import org.w3c.dom.*;
import org.w3c.dom.html.*;
import org.xml.sax.*;

/**
 * Preferred URL handling - reference implementation for the Sirsi Web2 Bridge.
 *<p>
 * Examine each search result record: based on the connector in use, locate the
 * preferred URL (if any) provided.
 *<p>
 * Add your own handler logic here.
 */
public class PreferredUrlHandler {
    private static org.apache.commons.logging.Log _log = LogUtils.getLog(PreferredUrlHandler.class);
    /**
     * American Social History Online
     */
    public static final String ASHO_CONNECTOR = "SRU_0001";

    /**
     * Connectors that can provide "preferred URLs"
     */
    public static final ArrayList _preferredUrlConnectors = new ArrayList();

    /****************************************************************************
     * Uncomment this static block to define the "preferred URL" provider(s)
     *
      static
      {
        _preferredUrlConnectors.add(ASHO_CONNECTOR);
      }
     *
     ****************************************************************************/

    /**
     * Fetch the preferred URL.  This method is invoked for every result record.
     *
     * @param connector Connector name
     * @param dataElement The result record (DATA element) to inspect
     * @return The preferred URL (null if none)
     */
    public static String getUrl(String connector, Element dataElement) {
        /*
         * Stop now if this connector can't provide a preferred URL
         */
        if (!_preferredUrlConnectors.contains(connector)) {
            return null;
        }
        /*
         * American Social History Online
         *
         * An example:
         *
         *    <DATA>
         *      ...
         *      <IDENTIFIER scheme="URL>http://preferred/url/here</IDENTIFIER>
         *      ...
         *    </DATA>
         *
         * We know each result record will have only one of these.
         */
        if (connector.equals(ASHO_CONNECTOR)) {
            NodeList nodeList = DomUtils.getElementList(dataElement, "IDENTIFIER");
            String url = null;

            for (int i = 0; i < nodeList.getLength(); i++) {
                Element element = (Element) nodeList.item(i);

                if (element.getAttribute("scheme").equals("URL")) {
                    url = DomUtils.getText(element);

                    if (StringUtils.isNull(url)) {
                        url = null;
                    }
                    break;
                }
            }
            return url;
        }
        /*
         * A known connector and we didn't handle it?
         */
        return null;
    }
}