001    // Copyright 2007, 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.internal.services;
016    
017    import org.apache.tapestry5.ioc.ObjectLocator;
018    import org.apache.tapestry5.ioc.annotations.Inject;
019    import org.apache.tapestry5.model.MutableComponentModel;
020    import org.apache.tapestry5.plastic.PlasticField;
021    import org.apache.tapestry5.services.transform.InjectionProvider2;
022    
023    /**
024     * A very late worker related to the {@link Inject} annotation that, when all other forms of injection have failed,
025     * matches the field type to a service interface.
026     */
027    public class ServiceInjectionProvider implements InjectionProvider2
028    {
029        private final ObjectLocator locator;
030    
031        private final ComponentClassCache classCache;
032    
033        public ServiceInjectionProvider(ObjectLocator locator, ComponentClassCache classCache)
034        {
035            this.locator = locator;
036            this.classCache = classCache;
037        }
038    
039        public boolean provideInjection(PlasticField field, ObjectLocator locator, MutableComponentModel componentModel)
040        {
041            Class fieldType = classCache.forName(field.getTypeName());
042    
043            Object inject = this.locator.getService(fieldType);
044    
045            assert inject != null;
046    
047            field.inject(inject);
048    
049            // If we make it this far without an exception, then we were successful
050            // and should claim the field.
051    
052            return true;
053        }
054    
055    }