org.eshark.xmlprog.cache.ClassCache.java Source code

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Here is the source code for org.eshark.xmlprog.cache.ClassCache.java

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/*
 * Licensed to the <Company Name> under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The <Supporter> licenses this file to You under the <Company Name> License, Version 1.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://<company site url>/addax-licenses//LICENSE-1.0
 * 
 * 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.eshark.xmlprog.cache;

import static org.apache.commons.lang.StringUtils.isEmpty;
import static org.apache.commons.lang.SystemUtils.getUserDir;
import static org.eshark.xmlprog.reflect.ClassUtils.getAppClass;

import java.io.File;
import java.io.IOException;
import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.ParserConfigurationException;

import org.eshark.xmlprog.api.GenericXMLCache;
import org.eshark.xmlprog.exception.XMLProgException;
import org.eshark.xmlprog.exception.XMLProgFormatException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class ClassCache extends GenericXMLCache {

    private static final long serialVersionUID = -3346813405555943467L;
    private static ClassCache CLASS_CACHE = null;
    public static String FILE_PATH = getUserDir().getAbsolutePath();
    public static String FILE_NAME = "class.cache.xml";
    // The required DTD URI for exported dql-cache
    private final String DTD_URI = "http://dtd/class-cache.dtd";
    private final String DTD = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + "<!-- DTD for class-cache -->"
            + "<!ELEMENT classes ( comment?, class* ) >" + "<!ATTLIST classes" + " version CDATA #FIXED \"1.0\">"
            + "<!ELEMENT comment (#PCDATA) >" + "<!ELEMENT class (#PCDATA) >" + "<!ATTLIST class "
            + " key CDATA #REQUIRED>";

    public Object clone() throws CloneNotSupportedException {
        return CLASS_CACHE;
    }

    // TOD0 :: sysnchronization is needed
    public static ClassCache getClassCache() {
        if (CLASS_CACHE == null)
            CLASS_CACHE = new ClassCache();
        return CLASS_CACHE;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.dematas.addax.common.cache.GenericXMLCache#loadFromXML(com.documentum.fc.client.IDfSession,
     *      java.lang.String, java.lang.String)
     */
    public void loadFromXML(File aXMLFile) throws XMLProgFormatException {
        try {
            DocumentBuilder lDocumentBuilder = getDocumentBuilder();
            lDocumentBuilder.setEntityResolver(new Resolver());
            // For XML
            Document lXMLDocument = null;
            if (aXMLFile == null)
                lXMLDocument = lDocumentBuilder.parse(new File(FILE_PATH + "\\xmls", FILE_NAME));
            else
                lXMLDocument = lDocumentBuilder.parse(aXMLFile);

            // normalize the document
            lXMLDocument.getDocumentElement().normalize();

            // Read the XML and create the cache
            Element daoElement = (Element) lXMLDocument.getChildNodes().item(1);
            String xmlVersion = daoElement.getAttribute("version");
            if (xmlVersion.compareTo(EXTERNAL_XML_VERSION) > 0)
                throw new XMLProgFormatException("Exported Class Cache file format version " + xmlVersion
                        + " is not supported. This XMLProg Configuration installation can read" + " versions "
                        + EXTERNAL_XML_VERSION + " or older. You" + " may need to check the configuration.");
            importClasses(daoElement);
        } catch (ParserConfigurationException PCE) {
            PCE.printStackTrace();
        } catch (SAXException SXE) {
            SXE.printStackTrace();
        } catch (IOException IOE) {
            IOE.printStackTrace();
        }
    }

    private void importClasses(Element xmlElement) {
        final String lKey = "key";
        NodeList entries = xmlElement.getChildNodes();
        int numEntries = entries.getLength();
        int start = numEntries > 0 && entries.item(0).getNodeName().equals("comment") ? 1 : 0;
        for (int i = start; i < numEntries; i++) {
            Element entry = (Element) entries.item(i);
            if (entry.hasAttribute(lKey)) {
                Node n = entry.getFirstChild();
                String val = (n == null) ? "" : n.getNodeValue();
                if (!isEmpty(val = val.trim())) {

                    try {
                        mXmlMap.put(entry.getAttribute(lKey), getAppClass(val));
                    } catch (XMLProgException XMLPE) {
                        XMLPE.printStackTrace();
                    } catch (ClassNotFoundException CNFE) {
                        CNFE.printStackTrace();
                    }
                    // For testing purpose
                    // Please delete later
                    System.out.println("CLASS KEY :: " + entry.getAttribute(lKey) + " VALUE :: " + val);
                }
            }
        }
    }

    private class Resolver implements EntityResolver {
        public InputSource resolveEntity(String pid, String sid) throws SAXException {
            if (sid.equals(DTD_URI)) {
                InputSource is;
                is = new InputSource(new StringReader(DTD));
                is.setSystemId(DTD_URI);
                return is;
            }
            throw new SAXException("Invalid system identifier : " + sid);
        }
    }

}