/*
* Copyright 1999-2005 The Apache Software Foundation.
*
* 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.apache.cocoon.transformation;
import java.io.IOException;
import java.io.Serializable;
import java.util.Map;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.caching.CacheableProcessingComponent;
import org.apache.cocoon.components.validation.ValidationHandler;
import org.apache.cocoon.components.validation.Validator;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.xml.ContentHandlerWrapper;
import org.apache.cocoon.xml.XMLConsumer;
import org.apache.cocoon.xml.XMLMulticaster;
import org.apache.excalibur.source.Source;
import org.apache.excalibur.source.SourceValidity;
import org.xml.sax.SAXException;
/**
* <p>The {@link ValidatingTransformer} provides a very simple {@link Transformer}
* validating documents while being processed in a Cocoon pipeline.</p>
*
* <p>The only defined (but not required) configuration for this component is
* <code><grammar><i>...string...</i></grammar></code>
* indicating the default grammar language of the schemas to use.</p>
*
* <p>This configuration parameter can be overridden by specifying the
* <code>grammar</code> parameter when using this {@link Transformer} in a
* pipeline.</p>
*
* <p>If no grammar is specified (either as a configuration, or a parameter) this
* transformer will instruct the {@link Validator} to try and guess the grammar
* of the schema being parsed.</p>
*
*/
public class ValidatingTransformer extends AbstractTransformer
implements Configurable, Serviceable, Disposable, CacheableProcessingComponent {
/** <p>The configured {@link ServiceManager} instance.</p> */
private ServiceManager serviceManager = null;
/** <p>The configured {@link Validator} instance.</p> */
private Validator validator = null;
/** <p>The configured default grammar language.</p> */
private String grammar = null;
/** <p>The {@link ValidationHandler} to use in this transformation.</p> */
private ValidationHandler handler = null;
/** <p>A unique key identifying the schema source for caching.</p> */
private String key = null;
/**
* <p>Create a new {@link ValidatingTransformer} instance.</p>
*/
public ValidatingTransformer() {
super();
}
/**
* <p>Contextualize this component instance specifying its associated
* {@link ServiceManager} instance.</p>
*
* @param manager the {@link ServiceManager} to associate with this component.
* @throws ServiceException if a dependancy of this could not be resolved.
*/
public void service(ServiceManager manager)
throws ServiceException {
this.serviceManager = manager;
this.validator = (Validator) manager.lookup(Validator.ROLE);
}
/**
* <p>Configure this component instance.</p>
*
* <p>The only defined (but not required) configuration for this component is
* <code><grammar><i>...string...</i></grammar></code>
* indicating the default grammar used by this transformer used for parsing
* schemas.</p>
*
* @param configuration a {@link Configuration} instance for this component.
* @throws ConfigurationException never thrown.
*/
public void configure(Configuration configuration)
throws ConfigurationException {
this.grammar = configuration.getChild("grammar").getValue(null);
}
/**
* <p>Dispose of this component instance releasing all previously acquired
* required instances back to the {@link ServiceManager}.</p>
*/
public void dispose() {
this.serviceManager.release(this.validator);
}
/**
* <p>Contextualize this component in the scope of a pipeline when a request
* is processed.</p>
*
* @param resolver the {@link SourceResolver} contextualized in this request.
* @param objectModel unused.
* @param source the source URI of the schema to validate against.
* @param parameters unused.
*/
public void setup(SourceResolver resolver, Map objectModel, String source,
Parameters parameters)
throws ProcessingException, SAXException, IOException {
Source s = null;
try {
s = resolver.resolveURI(source);
String g = parameters.getParameter("grammar", this.grammar);
if (g == null) {
this.handler = this.validator.getValidationHandler(s);
} else{
this.handler = this.validator.getValidationHandler(s, g);
}
} finally {
if (source != null) resolver.release(s);
}
}
/**
* <p>Specify the {@link XMLConsumer} receiving SAX events emitted by this
* {@link Transformer} instance in the scope of a request.</p>
*
* @param consumer the {@link XMLConsumer} to send SAX events to.
*/
public void setConsumer(XMLConsumer consumer) {
XMLConsumer handler = new ContentHandlerWrapper(this.handler, this.handler);
super.setConsumer(new XMLMulticaster(handler, consumer));
}
/**
* <p>Return the unique key to associated with the schema being processed in
* the scope of the request being processed for caching.</p>
*
* @return a non null {@link String} representing the unique key for the schema.
*/
public Serializable getKey() {
return this.key;
}
/**
* <p>Return the {@link SourceValidity} associated with the schema currently
* being processed in the scope of the request being processed.</p>
*
* @return a non null {@link SourceValidity} instance.
*/
public SourceValidity getValidity() {
return this.handler.getValidity();
}
/**
* <p>Recycle this component instance at the end of request processing.</p>
*/
public void recycle() {
this.handler = null;
this.key = null;
super.recycle();
}
}