001    // Copyright 2006, 2007, 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.internal.services;
016    
017    import org.apache.tapestry5.ioc.AnnotationProvider;
018    import org.apache.tapestry5.ioc.ObjectLocator;
019    import org.apache.tapestry5.ioc.services.MasterObjectProvider;
020    import org.apache.tapestry5.model.MutableComponentModel;
021    import org.apache.tapestry5.plastic.PlasticField;
022    import org.apache.tapestry5.services.transform.InjectionProvider2;
023    
024    import java.lang.annotation.Annotation;
025    
026    /**
027     * Worker for the {@link org.apache.tapestry5.ioc.annotations.Inject} annotation that delegates out to the master
028     * {@link org.apache.tapestry5.ioc.services.MasterObjectProvider} to access the value. This worker must be scheduled
029     * after certain other workers, such as {@link BlockInjectionProvider} (which is keyed off a combination of type and
030     * the Inject annotation).
031     *
032     * @see org.apache.tapestry5.ioc.services.MasterObjectProvider
033     */
034    public class DefaultInjectionProvider implements InjectionProvider2
035    {
036        private final MasterObjectProvider masterObjectProvider;
037    
038        private final ObjectLocator locator;
039    
040        private final ComponentClassCache classCache;
041    
042        public DefaultInjectionProvider(MasterObjectProvider masterObjectProvider, ObjectLocator locator, ComponentClassCache classCache)
043        {
044            this.masterObjectProvider = masterObjectProvider;
045            this.locator = locator;
046            this.classCache = classCache;
047        }
048    
049        public boolean provideInjection(final PlasticField field, ObjectLocator locator, MutableComponentModel componentModel)
050        {
051            Class fieldType = classCache.forName(field.getTypeName());
052    
053            Object injectionValue = masterObjectProvider.provide(fieldType, new AnnotationProvider()
054            {
055                public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
056                {
057                    return field.getAnnotation(annotationClass);
058                }
059            }, this.locator, false);
060    
061            // Null means that no ObjectProvider could provide the value. We have set up the chain of
062            // command so that InjectResources can give it a try next. Later, we'll try to match against
063            // a service.
064    
065            if (injectionValue != null)
066            {
067                field.inject(injectionValue);
068                return true;
069            }
070    
071            return false;
072        }
073    }