org.springmodules.remoting.xmlrpc.dom.XmlRpcDtdResolver.java Source code

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Here is the source code for org.springmodules.remoting.xmlrpc.dom.XmlRpcDtdResolver.java

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/* 
 * Created on Jun 4, 2005
 *
 * 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.
 *
 * Copyright @2005 the original author or authors.
 */
package org.springmodules.remoting.xmlrpc.dom;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;

/**
 * <p>
 * Implementation of <code>{@link EntityResolver}</code> for the XML-RPC DTD,
 * to load the DTD from the Spring Modules class path (or JAR file).
 * </p>
 * <p>
 * Fetches "xml-rpc.dtd" from the class path resource
 * "/org/springmodules/remoting/xmlrpc/xml-rpc.dtd",
 * </p>
 * 
 * @author Alex Ruiz
 * 
 * @version $Revision$ $Date$
 */
public class XmlRpcDtdResolver implements EntityResolver {

    /**
     * Name of the DTD to use.
     */
    private static final String DTD_NAME = "xml-rpc";

    /**
     * Package where to search the DTD from.
     */
    private static final String SEARCH_PACKAGE = "/org/springmodules/remoting/xmlrpc/";

    /**
     * Message logger.
     */
    protected final Log logger = LogFactory.getLog(getClass());

    /**
     * Constructor.
     */
    public XmlRpcDtdResolver() {
        super();
    }

    /**
     * @see EntityResolver#resolveEntity(String, String)
     */
    public InputSource resolveEntity(String publicId, String systemId) {
        if (logger.isDebugEnabled()) {
            logger.debug("Trying to resolve XML entity with public ID [" + publicId + "] and system ID [" + systemId
                    + "]");
        }
        if (systemId != null && systemId.indexOf(DTD_NAME) > systemId.lastIndexOf("/")) {
            String dtdFile = systemId.substring(systemId.indexOf(DTD_NAME));

            if (logger.isDebugEnabled()) {
                logger.debug("Trying to locate [" + dtdFile + "] under [" + SEARCH_PACKAGE + "]");
            }

            try {
                Resource resource = new ClassPathResource(SEARCH_PACKAGE + dtdFile, getClass());
                InputSource source = new InputSource(resource.getInputStream());
                source.setPublicId(publicId);
                source.setSystemId(systemId);

                if (logger.isDebugEnabled()) {
                    logger.debug("Found beans DTD [" + systemId + "] in classpath");
                }
                return source;

            } catch (IOException ex) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Could not resolve beans DTD [" + systemId + "]: not found in class path", ex);
                }
            }
        }
        return null;
    }

}