org.topazproject.xml.transform.cache.CachedSource.java Source code

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Here is the source code for org.topazproject.xml.transform.cache.CachedSource.java

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/* $HeadURL::                                                                                     $
 * $Id$
 *
 * Copyright (c) 2006-2010 by Public Library of Science
 * http://plos.org
 * http://ambraproject.org
 *
 * 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.topazproject.xml.transform.cache;

import java.io.InputStream;
import java.io.IOException;
import java.util.Properties;

import javax.xml.transform.Source;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.topazproject.xml.transform.EntityResolvingSource;
import org.topazproject.xml.transform.URLRetriever;
import org.topazproject.xml.transform.NetworkURLRetriever;
import org.topazproject.xml.transform.ResourceURLRetriever;
import org.topazproject.xml.transform.MemoryCacheURLRetriever;
import org.topazproject.xml.transform.CustomEntityResolver;

/**
 * Creates a {@link Source} that can be used in a {@link javax.xml.transform.Transformer#transform}
 * call with most topaz/ambra entities cached.
 *
 * For example:
 * <pre>
 *   Transformer transformer = ...
 *   InputSource myInputSource = new InputSource(new FileReader(inFileName));
 *   transformer.transform(new CachedSource(myInputSource), new StreamResult(outFileName));
 * </pre>
 *
 * @author Eric Brown and Ronald Tschalr
 * @version $Id$
 */
public class CachedSource extends EntityResolvingSource implements Source {
    private static final Log log = LogFactory.getLog(CachedSource.class);
    private static final String DEF_MAP = "url_rsrc_map.properties";
    private static final EntityResolver resolver;

    static {
        URLRetriever r = new NetworkURLRetriever();
        try {
            Properties urlMap = new Properties();
            InputStream is = CachedSource.class.getResourceAsStream(DEF_MAP);
            if (is != null) {
                urlMap.load(is);
                r = new ResourceURLRetriever(r, urlMap, CachedSource.class);
            } else
                log.error("url-map resource '" + DEF_MAP + "' not found - no map loaded");
        } catch (IOException ioe) {
            log.error("Error loading entity-cache map - continuing without it", ioe);
        }
        resolver = new CustomEntityResolver(new MemoryCacheURLRetriever(r));
    }

    /**
     * Construct a new CachedSource object.
     *
     * @param src is the source of the XML document
     * @throws SAXException if we're unable to create an XMLReader (should never happen)
     */
    public CachedSource(InputSource src) throws SAXException {
        super(src, resolver);
    }

    /**
     * @return the EntityResolver.
     */
    public static EntityResolver getResolver() {
        return resolver;
    }
}