/*
* Copyright 2007 Joachim Grueneis
*
* 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.exolab.castor.xml.util.resolvers;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.castor.mapping.BindingType;
import org.castor.mapping.MappingUnmarshaller;
import org.exolab.castor.mapping.Mapping;
import org.exolab.castor.mapping.MappingException;
import org.exolab.castor.mapping.MappingLoader;
import org.exolab.castor.xml.ResolverException;
import org.exolab.castor.xml.XMLClassDescriptor;
import org.exolab.castor.xml.XMLConstants;
/**
* Tries to load the package mapping file for the given package.
* <br/>
* If the mapping file is available and could be loaded properly the
* descriptors listed in it are added to the description class cache
* of the configuration.
* <br/>
* To disable loading of pacakge mapping files just don't use this
* command.
* <br/>
* If a mapping file is not available for the given package this method
* will not load any descriptors and not throw any exceptions.<br/>
* The class loader specified in the configuration is used.
* <br/>
* The mapping file - if available - is loaded using the
* <code>MappingLoader</code>.<br/>
* <br/>
* Further calls to this command with the same package name will not be
* processed.
*
* @author <a href="mailto:jgrueneis AT gmail DOT com">Joachim Grueneis</a>
* @author <a href="mailto:stevendolg AT gxm DOT at">Steven Dolg</a>
* @version $Revision$ $Date$
* @since 1.2
*/
public class ByPackageMapping extends AbstractResolverPackageCommand {
private static final Log LOG = LogFactory.getLog(ByPackageMapping.class);
private ArrayList _loadedPackages = new ArrayList();
/**
* No specific stuff needed.
*/
public ByPackageMapping() {
super();
}
/**
* Loads a package mapping file for the given package name using the
* provided ClassLoader.
*
* @param packageName The name of the package to load the mapping file for.
* @return The loaded Mapping or <code>null</code> if no mapping file
* is available for the given package.
* @throws MappingException
*/
private Mapping loadMapping(final String packageName, final ClassLoader classLoader)
throws MappingException {
URL url = classLoader.getResource(ResolveHelpers.getQualifiedFileName(
XMLConstants.PKG_MAPPING_FILE, packageName));
if (url == null) { return null; }
try {
Mapping mapping = new Mapping(classLoader);
mapping.loadMapping(url);
return mapping;
} catch (java.io.IOException ioex) {
throw new MappingException(ioex);
}
}
/**
* {@inheritDoc}
*/
protected Map internalResolve(final String packageName, final ClassLoader classLoader,
final Map properties) throws ResolverException {
HashMap results = new HashMap();
if (!isEmptyPackageName(packageName) && _loadedPackages.contains(packageName)) {
if (LOG.isDebugEnabled()) {
LOG.debug("Package: " + packageName + " has already been loaded.");
}
return results;
}
if (!isEmptyPackageName(packageName)) _loadedPackages.add(packageName);
try {
final Mapping mapping = this.loadMapping(packageName, classLoader);
if (mapping != null) {
MappingUnmarshaller unmarshaller = new MappingUnmarshaller();
// TODO: Joachim 2007-09-07 the InternalContext should be set into the unmarshaller!
MappingLoader mappingLoader = unmarshaller.getMappingLoader(mapping, BindingType.XML);
Iterator descriptors = mappingLoader.descriptorIterator();
while (descriptors.hasNext()) {
XMLClassDescriptor descriptor = (XMLClassDescriptor) descriptors.next();
if (LOG.isDebugEnabled()) {
LOG.debug("Found descriptor: " + descriptor);
}
results.put(descriptor.getJavaClass().getName(), descriptor);
}
}
} catch (MappingException e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Ignored exception: " + e + " while loading mapping for package: "
+ packageName);
}
}
return results;
}
}