001    // Copyright 2006, 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    
015    package org.apache.tapestry5.ioc.internal;
016    
017    import java.util.Collection;
018    
019    import org.apache.tapestry5.ioc.Configuration;
020    import org.apache.tapestry5.ioc.ObjectLocator;
021    
022    /**
023     * Wraps a {@link java.util.Collection} as a {@link org.apache.tapestry5.ioc.Configuration} and perform validation that
024     * collected value are of the correct type.
025     */
026    public class ValidatingConfigurationWrapper<T> extends AbstractConfigurationImpl<T> implements Configuration<T>
027    {
028        private final TypeCoercerProxy typeCoercer;
029    
030        private final String serviceId;
031    
032        private final Class<T> expectedType;
033    
034        private final Collection<T> collection;
035    
036        public ValidatingConfigurationWrapper(Class<T> expectedType, ObjectLocator locator, TypeCoercerProxy typeCoercer,
037                Collection<T> collection, String serviceId)
038        {
039            super(expectedType, locator);
040            this.typeCoercer = typeCoercer;
041    
042            this.collection = collection;
043            this.serviceId = serviceId;
044            this.expectedType = expectedType;
045        }
046    
047        public void add(T object)
048        {
049            if (object == null)
050                throw new NullPointerException(IOCMessages.contributionWasNull(serviceId));
051    
052            T coerced = typeCoercer.coerce(object, expectedType);
053    
054            collection.add(coerced);
055        }
056    
057        public void addInstance(Class<? extends T> clazz)
058        {
059            add(instantiate(clazz));
060        }
061    }