/*
* 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.components.treeprocessor.sitemap;
import org.apache.avalon.framework.component.ComponentException;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.Composable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.logger.Logger;
import org.apache.cocoon.Constants;
import org.apache.cocoon.ResourceNotFoundException;
import org.apache.cocoon.components.notification.Notifying;
import org.apache.cocoon.components.notification.NotifyingBuilder;
import org.apache.cocoon.components.pipeline.ProcessingPipeline;
import org.apache.cocoon.components.treeprocessor.InvokeContext;
import org.apache.cocoon.components.treeprocessor.ProcessingNode;
import org.apache.cocoon.environment.Environment;
import org.apache.cocoon.environment.ObjectModelHelper;
import java.io.IOException;
import java.util.Map;
/**
* Helps to call error handlers from PipelineNode and PipelinesNode.
*
* @author <a href="mailto:juergen.seitz@basf-it-services.com">Jürgen Seitz</a>
* @author <a href="mailto:bluetkemeier@s-und-n.de">Björn Lütkemeier</a>
* @version $Id: ErrorHandlerHelper.java 161179 2005-04-13 13:24:55Z vgritsenko $
*/
public class ErrorHandlerHelper extends AbstractLogEnabled
implements Composable {
private ComponentManager manager;
/**
* Logger for handled errors
*/
protected Logger handledErrorsLogger;
/**
* Error handling node for the ResourceNotFoundException
* (deprecated)
*/
private HandleErrorsNode error404;
/**
* Error handling node for all other exceptions
*/
private HandleErrorsNode error500;
public void enableLogging(Logger logger) {
super.enableLogging(logger);
this.handledErrorsLogger = logger.getChildLogger("handled-errors");
}
/**
* The component manager is used to create notifying builders.
*/
public void compose(ComponentManager manager) {
this.manager = manager;
}
void set404Handler(ProcessingNode node) {
this.error404 = (HandleErrorsNode) node;
}
void set500Handler(ProcessingNode node) {
this.error500 = (HandleErrorsNode) node;
}
/**
* @return true if has no error handler nodes set
*/
public boolean isEmpty() {
return this.error404 == null && this.error500 == null;
}
public boolean isInternal() {
return this.error500 != null && this.error500.isInternal();
}
public boolean isExternal() {
return this.error500 != null && this.error500.isExternal();
}
/**
* Handle error.
*/
public boolean invokeErrorHandler(Exception ex,
Environment env,
InvokeContext context)
throws Exception {
return prepareErrorHandler(ex, env, context) != null;
}
/**
* Prepare error handler for the internal pipeline error handling.
*
* <p>If building pipeline only, error handling pipeline will be
* built and returned. If building and executing pipeline,
* error handling pipeline will be built and executed.</p>
*/
public ProcessingPipeline prepareErrorHandler(Exception ex,
Environment env,
InvokeContext context)
throws Exception {
boolean internal = !env.isExternal() && !env.isInternalRedirect();
if (internal && !isInternal()) {
// Propagate exception on internal request: No internal handler.
throw ex;
} else if (!internal && !isExternal()) {
// Propagate exception on external request: No external handler.
throw ex;
} else if (!internal && error404 != null && ex instanceof ResourceNotFoundException) {
// Invoke 404-specific handler: Only on external requests. Deprecated.
return prepareErrorHandler(error404, ex, env, context);
} else if (error500 != null) {
// Invoke global handler
return prepareErrorHandler(error500, ex, env, context);
}
// Exception was not handled in this error handler, propagate.
throw ex;
}
/**
* Handle error using specified error handler processing node.
*/
public boolean invokeErrorHandler(ProcessingNode node,
Exception ex,
Environment env,
InvokeContext context)
throws Exception {
return prepareErrorHandler(node, ex, env, context) != null;
}
/**
* Prepare (or execute) error handler using specified error handler
* processing node.
*
* <p>If building pipeline only, error handling pipeline will be
* built and returned. If building and executing pipeline,
* error handling pipeline will be built and executed.</p>
*/
private ProcessingPipeline prepareErrorHandler(ProcessingNode node,
Exception ex,
Environment env,
InvokeContext context)
throws Exception {
if (ex instanceof ResourceNotFoundException) {
this.handledErrorsLogger.error(ex.getMessage());
} else {
this.handledErrorsLogger.error(ex.getMessage(), ex);
}
try {
prepare(context, env, ex);
// Create error context
InvokeContext errorContext = new InvokeContext(context.isBuildingPipelineOnly());
errorContext.enableLogging(getLogger());
errorContext.setRedirector(context.getRedirector());
errorContext.compose(this.manager);
try {
// Process error handling node
if (node.invoke(env, errorContext)) {
// Exception was handled.
return errorContext.getProcessingPipeline();
}
} finally {
errorContext.dispose();
}
} catch (Exception e) {
getLogger().error("An exception occured while handling errors at " + node.getLocation(), e);
// Rethrow it: It will either be handled by the parent sitemap or by the environment (e.g. Cocoon servlet)
throw e;
}
// Exception was not handled in this error handler, propagate.
throw ex;
}
/**
* Build notifying object
*/
private void prepare(InvokeContext context, Environment env, Exception ex)
throws IOException, ComponentException {
Map objectModel = env.getObjectModel();
if (objectModel.get(Constants.NOTIFYING_OBJECT) == null) {
// error has not been processed by another handler before
// Try to reset the response to avoid mixing already produced output
// and error page.
if (!context.isBuildingPipelineOnly()) {
env.tryResetResponse();
}
// Create a Notifying
NotifyingBuilder notifyingBuilder = (NotifyingBuilder) this.manager.lookup(NotifyingBuilder.ROLE);
Notifying currentNotifying = null;
try {
currentNotifying = notifyingBuilder.build(this, ex);
} finally {
this.manager.release(notifyingBuilder);
}
// Add it to the object model
objectModel.put(Constants.NOTIFYING_OBJECT, currentNotifying);
// Also add the exception
objectModel.put(ObjectModelHelper.THROWABLE_OBJECT, ex);
}
}
}