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
015package org.apache.tapestry5.internal.services;
016
017import org.apache.tapestry5.commons.AnnotationProvider;
018import org.apache.tapestry5.commons.ObjectLocator;
019import org.apache.tapestry5.ioc.services.MasterObjectProvider;
020import org.apache.tapestry5.model.MutableComponentModel;
021import org.apache.tapestry5.plastic.PlasticField;
022import org.apache.tapestry5.services.transform.InjectionProvider2;
023
024import 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 */
034public 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}