org.springframework.webflow.engine.FlowExecutionExceptionHandlerSet Maven / Gradle / Ivy
/*
* Copyright 2004-2007 the original author or authors.
*
* 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.springframework.webflow.engine;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import org.springframework.core.style.StylerUtils;
import org.springframework.webflow.core.collection.CollectionUtils;
import org.springframework.webflow.execution.FlowExecutionException;
import org.springframework.webflow.execution.ViewSelection;
/**
* A typed set of state exception handlers, mainly for use internally by
* artifacts that can apply state exception handling logic.
*
* @see FlowExecutionExceptionHandler
* @see Flow#getExceptionHandlerSet()
* @see State#getExceptionHandlerSet()
*
* @author Keith Donald
*/
public class FlowExecutionExceptionHandlerSet {
/**
* The set of exception handlers.
*/
private List exceptionHandlers = new LinkedList();
/**
* Add a state exception handler to this set.
* @param exceptionHandler the exception handler to add
* @return true if this set's contents changed as a result of the add
* operation
*/
public boolean add(FlowExecutionExceptionHandler exceptionHandler) {
if (contains(exceptionHandler)) {
return false;
}
return exceptionHandlers.add(exceptionHandler);
}
/**
* Add a collection of state exception handler instances to this set.
* @param exceptionHandlers the exception handlers to add
* @return true if this set's contents changed as a result of the add
* operation
*/
public boolean addAll(FlowExecutionExceptionHandler[] exceptionHandlers) {
return CollectionUtils.addAllNoDuplicates(this.exceptionHandlers, exceptionHandlers);
}
/**
* Tests if this state exception handler is in this set.
* @param exceptionHandler the exception handler
* @return true if the state exception handler is contained in this set,
* false otherwise
*/
public boolean contains(FlowExecutionExceptionHandler exceptionHandler) {
return exceptionHandlers.contains(exceptionHandler);
}
/**
* Remove the exception handler instance from this set.
* @param exceptionHandler the exception handler to add
* @return true if this set's contents changed as a result of the remove
* operation
*/
public boolean remove(FlowExecutionExceptionHandler exceptionHandler) {
return exceptionHandlers.remove(exceptionHandler);
}
/**
* Returns the size of this state exception handler set.
* @return the exception handler set size
*/
public int size() {
return exceptionHandlers.size();
}
/**
* Convert this list to a typed state exception handler array.
* @return the exception handler list, as a typed array
*/
public FlowExecutionExceptionHandler[] toArray() {
return (FlowExecutionExceptionHandler[])exceptionHandlers.toArray(new FlowExecutionExceptionHandler[exceptionHandlers.size()]);
}
/**
* Handle an exception that occured during the context of the current flow
* execution request.
*
* This implementation iterates over the ordered set of exception handler
* objects, delegating to each handler in the set until one handles the
* exception that occured and selects a non-null error view.
* @param exception the exception that occured
* @param context the flow execution control context
* @return the selected error view, or null if no handler
* matched or returned a non-null view selection
*/
public ViewSelection handleException(FlowExecutionException exception, RequestControlContext context) {
Iterator it = exceptionHandlers.iterator();
while (it.hasNext()) {
FlowExecutionExceptionHandler handler = (FlowExecutionExceptionHandler)it.next();
if (handler.handles(exception)) {
ViewSelection result = handler.handle(exception, context);
if (result != null) {
return result;
}
// else continue with next handler
}
}
return null;
}
public String toString() {
return StylerUtils.style(exceptionHandlers);
}
}