001// Copyright 2008, 2010 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.internal.services;
016
017import java.io.IOException;
018
019import org.apache.tapestry5.TrackableComponentEventCallback;
020import org.apache.tapestry5.services.ComponentEventResultProcessor;
021
022/**
023 * A wrapper around {@link ComponentEventResultProcessor} that encapsulates capturing the exception.
024 */
025@SuppressWarnings({ "unchecked", "rawtypes" })
026public class ComponentResultProcessorWrapper implements TrackableComponentEventCallback
027{
028    private boolean aborted;
029
030    private IOException exception;
031
032    private final ComponentEventResultProcessor processor;
033    
034    private Object result;
035
036    public ComponentResultProcessorWrapper(ComponentEventResultProcessor processor)
037    {
038        this.processor = processor;
039    }
040
041    public boolean handleResult(Object result)
042    {
043        if (aborted)
044            throw new IllegalStateException(
045                    "Event callback has already received and processed a result value and can not do so again.");
046
047        this.result = result;
048        
049        try
050        {
051            processor.processResultValue(result);
052        }
053        catch (IOException ex)
054        {
055            exception = ex;
056        }
057
058        aborted = true;
059
060        return true;
061    }
062
063    /**
064     * Returns true if {@link org.apache.tapestry5.ComponentEventCallback#handleResult(Object)} was invoked, false
065     * otherwise.
066     * 
067     * @return true if the event was aborted
068     */
069    public boolean isAborted()
070    {
071        return aborted;
072    }
073
074    public void rethrow() throws IOException
075    {
076        if (exception != null)
077            throw exception;
078    }
079    
080    public Object getResult() 
081    {
082        return result;
083    }
084
085}