ListRecords.java

/*
 *  -------------------------------------------------------------------------
 *  Copyright 2006 OCLC, Online Computer Library Center
 *  Copyright 2014 
 *  Centre for Information Modeling - Austrian Centre for Digital Humanities
 *
 *  Licensed under the Apache 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.apache.org/licenses/LICENSE-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 org.emile.cirilo.oai;

import java.io.IOException;
import java.net.URLEncoder;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;
import org.xml.sax.SAXException;
import org.apache.xerces.impl.dv.util.Base64;

/**
 * This class represents an ListRecords response on either the server or
 * on the client
 *
 * @author Jeffrey A. Young, OCLC Online Computer Library Center
 */
public class ListRecords extends HarvesterVerb {
    /**
     * Mock object constructor (for unit testing purposes)
     */
    public ListRecords() {
        super();
    }
    
    /**
     * Client-side ListRecords verb constructor
     *
     * @param baseURL the baseURL of the server to be queried
     * @exception MalformedURLException the baseURL is bad
     * @exception SAXException the xml response is bad
     * @exception IOException an I/O error occurred
     */
    public ListRecords(String baseURL, String from, String until,
            String set, String metadataPrefix)
    throws IOException, ParserConfigurationException, SAXException,
    TransformerException {
        super(getRequestURL(baseURL, from, until, set, metadataPrefix));
    }
    
    /**
     * Client-side ListRecords verb constructor (resumptionToken version)
     * @param baseURL
     * @param resumptionToken
     * @throws IOException
     * @throws ParserConfigurationException
     * @throws SAXException
     * @throws TransformerException
     */
    public ListRecords(String baseURL, String resumptionToken)
    throws IOException, ParserConfigurationException, SAXException,
    TransformerException {
        super(getRequestURL(baseURL, resumptionToken));
    }
    
    /**
     * Get the oai:resumptionToken from the response
     * 
     * @return the oai:resumptionToken value
     * @throws TransformerException
     * @throws NoSuchFieldException
     */
    public String getResumptionToken()
    throws TransformerException, NoSuchFieldException {
        String schemaLocation = getSchemaLocation();
        if (schemaLocation.indexOf(SCHEMA_LOCATION_V2_0) != -1) {
            return getSingleString("/oai20:OAI-PMH/oai20:ListRecords/oai20:resumptionToken");
        } else if (schemaLocation.indexOf(SCHEMA_LOCATION_V1_1_LIST_RECORDS) != -1) {
            return getSingleString("/oai11_ListRecords:ListRecords/oai11_ListRecords:resumptionToken");
        } else {
            throw new NoSuchFieldException(schemaLocation);
        }
    }
    
    /**
     * Construct the query portion of the http request
     *
     * @return a String containing the query portion of the http request
     */
    private static String getRequestURL(String baseURL, String from,
            String until, String set,
            String metadataPrefix) {
        StringBuffer requestURL =  new StringBuffer(baseURL);
        requestURL.append("?verb=ListRecords");
        if (from != null) requestURL.append("&from=").append(from);
        if (until != null) requestURL.append("&until=").append(until);
        if (set != null) requestURL.append("&set=").append(set);
        requestURL.append("&metadataPrefix=").append(metadataPrefix);
        return requestURL.toString();
    }
    
    /**
     * Construct the query portion of the http request (resumptionToken version)
     * @param baseURL
     * @param resumptionToken
     * @return
     */
    private static String getRequestURL(String baseURL,
            String resumptionToken) {
  	
        StringBuffer requestURL =  new StringBuffer(baseURL);
        requestURL.append("?verb=ListRecords");
        try {
        	requestURL.append("&resumptionToken=").append(URLEncoder.encode(resumptionToken, "UTF-8"));
        } catch (Exception e) {}
        return requestURL.toString();
    }
}