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.services;
016    
017    import org.apache.tapestry5.ioc.AnnotationProvider;
018    import org.apache.tapestry5.ioc.ObjectLocator;
019    import org.apache.tapestry5.ioc.ObjectProvider;
020    
021    /**
022     * Provides a single object of a given type.
023     *
024     * @since 5.3
025     */
026    public class StaticObjectProvider<S> implements ObjectProvider
027    {
028        private final Class<S> valueType;
029    
030        private final S value;
031    
032        public StaticObjectProvider(Class<S> valueType, S value)
033        {
034            this.valueType = valueType;
035            this.value = value;
036    
037            assert valueType != null;
038            assert value != null;
039        }
040    
041    
042        public <T> T provide(Class<T> objectType, AnnotationProvider annotationProvider, ObjectLocator locator)
043        {
044            if (objectType == valueType)
045            {
046                return objectType.cast(value);
047            }
048    
049            return null;
050        }
051    }