de.ingrid.iplug.opensearch.query.OSDescriptorBuilder.java Source code

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Here is the source code for de.ingrid.iplug.opensearch.query.OSDescriptorBuilder.java

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/*
 * **************************************************-
 * ingrid-iplug-opensearch:war
 * ==================================================
 * Copyright (C) 2014 - 2017 wemove digital solutions GmbH
 * ==================================================
 * Licensed under the EUPL, Version 1.1 or  as soon they will be
 * approved by the European Commission - subsequent versions of the
 * EUPL (the "Licence");
 * 
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * 
 * http://ec.europa.eu/idabc/eupl5
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 * **************************************************#
 */
package de.ingrid.iplug.opensearch.query;

import java.io.InputStream;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import de.ingrid.iplug.opensearch.communication.OSCommunication;

/**
 * This class takes care of receiving the Opensearch-Descriptor
 * @author Andr Wallat
 *
 */
public class OSDescriptorBuilder {
    private static Log log = LogFactory.getLog(OSDescriptorBuilder.class);

    /**
     * Create a descriptor object that holds all the information necessary. If
     * a descriptor was given, the OS-Interface is requested. If not then the
     * template-url (according to Opensearch-standard) provided will be used
     * along with the type 'application/rss+xml'.
     * 
     * @param serviceUrl
     * @param isDescriptor
     * @return
     * @throws Exception
     */
    public OSDescriptor createDescriptor(String serviceUrl, boolean isDescriptor) throws Exception {
        if (isDescriptor) {
            return receiveDescriptor(serviceUrl);
        } else {
            OSDescriptor osDesciptor = new OSDescriptor();
            osDesciptor.setTypeAndUrl("application/rss+xml", serviceUrl);
            return osDesciptor;
        }
    }

    /**
     * Request the descriptorAddress and return an OSDescriptor object.
     * 
     * @param descriptorAddress
     * @return
     * @throws Exception
     */
    public OSDescriptor receiveDescriptor(String descriptorAddress) throws Exception {
        OSCommunication comm = new OSCommunication();
        OSDescriptor osDesciptor = new OSDescriptor();

        try {
            InputStream response = comm.sendRequest(descriptorAddress);

            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document descriptorDoc = builder.parse(response);

            XPath xpath = XPathFactory.newInstance().newXPath();
            NodeList typeList = (NodeList) xpath.evaluate("/OpenSearchDescription/Url/@type", descriptorDoc,
                    XPathConstants.NODESET);
            NodeList templateList = (NodeList) xpath.evaluate("/OpenSearchDescription/Url/@template", descriptorDoc,
                    XPathConstants.NODESET);

            for (int i = 0; i < typeList.getLength(); i++) {
                osDesciptor.setTypeAndUrl(typeList.item(i).getTextContent(), templateList.item(i).getTextContent());
            }
        } catch (ParserConfigurationException e) {
            log.error("Error while parsing DescriptorFile from: " + descriptorAddress);
            e.printStackTrace();
        } catch (SAXException e) {
            log.error("Error while parsing DescriptorFile from: " + descriptorAddress);
            e.printStackTrace();
        } catch (XPathExpressionException e) {
            log.error("Error while parsing DescriptorFile from: " + descriptorAddress);
            e.printStackTrace();
        } finally {
            comm.releaseConnection();
        }
        return osDesciptor;
    }

    /**
     * Check for a certain type inside a document.
     * 
     * @param nodeList
     * @param type
     * @return
     */
    /*private boolean nodeListContainsType(NodeList nodeList, String type) {
           
       for (int i=0; i<nodeList.getLength(); i++) {
     if (nodeList.item(i).getTextContent().equals(type)) {
        return true;
     }
       }
       return false;
    }*/

    /**
     * Print all the types offered in this document.
     * @param nodeList
     * @return
     */
    /*private String printTypes(NodeList nodeList) {
       String result = "";
       for (int i=0; i<nodeList.getLength(); i++) {
     result += nodeList.item(i).getTextContent() +"\n";
       }
       return result;
    }*/
}