    001// Copyright 2007, 2008, 2010, 2011 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 org.apache.tapestry5.commons.util.AvailableValues;
    018import org.apache.tapestry5.commons.util.UnknownValueException;
    019import org.apache.tapestry5.func.F;
    020import org.apache.tapestry5.func.Mapper;
    021import org.apache.tapestry5.plastic.PlasticUtils;
    022import org.apache.tapestry5.services.ComponentEventResultProcessor;
    023
    024import java.io.IOException;
    025import java.util.Collection;
    026import java.util.List;
    027
    028/**
    029 * A catch-all for type Object that reports the return value as an error.
    030 */
    031@SuppressWarnings("unchecked")
    032public class ObjectComponentEventResultProcessor implements ComponentEventResultProcessor<Object>
    033{
    034    private final Collection<Class> configuredClasses;
    035
    036    public ObjectComponentEventResultProcessor(Collection<Class> configuredClasses)
    037    {
    038        this.configuredClasses = configuredClasses;
    039    }
    040
    041    public void processResultValue(Object value) throws IOException
    042    {
    043        List<String> names = F.flow(configuredClasses).map(new Mapper<Class, String>()
    044        {
    045            public String map(Class input)
    046            {
    047                return PlasticUtils.toTypeName(input);
    048            }
    049        }).toList();
    050
    051        String message = String.format(
    052                "A component event handler method returned the value %s. Return type %s can not be handled.", value,
    053                PlasticUtils.toTypeName(value.getClass()));
    054
    055        throw new UnknownValueException(message, new AvailableValues("Configured return types", names));
    056    }
    057}