001    // Copyright 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    
015    package org.apache.tapestry5.ioc.internal.util;
016    
017    import org.apache.tapestry5.ioc.Invokable;
018    import org.apache.tapestry5.ioc.ObjectCreator;
019    
020    import java.lang.reflect.Constructor;
021    import java.lang.reflect.InvocationTargetException;
022    
023    /**
024     * Wraps the invocation of a constructor (with exception reporting) as an {@link Invokable}.
025     *
026     * @since 5.3
027     */
028    public class ConstructorInvoker<T> implements Invokable<T>
029    {
030        private final Constructor<T> constructor;
031    
032        private final ObjectCreator[] constructorParameters;
033    
034        public ConstructorInvoker(Constructor constructor, ObjectCreator[] constructorParameters)
035        {
036            this.constructor = constructor;
037            this.constructorParameters = constructorParameters;
038        }
039    
040        public T invoke()
041        {
042            Throwable fail;
043    
044            Object[] realized = InternalUtils.realizeObjects(constructorParameters);
045    
046            try
047            {
048                return constructor.newInstance(realized);
049            } catch (InvocationTargetException ex)
050            {
051                fail = ex.getTargetException();
052            } catch (Exception ex)
053            {
054                fail = ex;
055            }
056    
057            throw new RuntimeException(String.format("Error invoking constructor %s: %s",
058                    constructor, InternalUtils.toMessage(fail)), fail);
059        }
060    }