001// Copyright 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 015package org.apache.tapestry5.internal.services; 016 017import org.apache.tapestry5.Block; 018import org.apache.tapestry5.ComponentResources; 019import org.apache.tapestry5.annotations.Id; 020import org.apache.tapestry5.internal.transform.ReadOnlyComponentFieldConduit; 021import org.apache.tapestry5.ioc.ObjectLocator; 022import org.apache.tapestry5.ioc.annotations.Inject; 023import org.apache.tapestry5.ioc.internal.util.InternalUtils; 024import org.apache.tapestry5.model.MutableComponentModel; 025import org.apache.tapestry5.plastic.FieldConduit; 026import org.apache.tapestry5.plastic.InstanceContext; 027import org.apache.tapestry5.plastic.PlasticField; 028import org.apache.tapestry5.services.transform.InjectionProvider2; 029 030/** 031 * Identifies fields of type {@link Block} that have the {@link Inject} annotation and converts them 032 * into read-only 033 * fields containing the injected Block from the template. The annotation's value is the id of the 034 * block to inject; if 035 * omitted, the block id is deduced from the field id. 036 * <p/> 037 * Must be scheduled before {@link DefaultInjectionProvider} because it uses the same annotation, Inject, with a 038 * different interpretation. 039 */ 040public class BlockInjectionProvider implements InjectionProvider2 041{ 042 private static final String BLOCK_TYPE_NAME = Block.class.getName(); 043 044 public boolean provideInjection(PlasticField field, ObjectLocator locator, MutableComponentModel componentModel) 045 { 046 if (!field.getTypeName().equals(BLOCK_TYPE_NAME)) 047 { 048 return false; 049 } 050 051 Id annotation = field.getAnnotation(Id.class); 052 053 String blockId = getBlockId(field.getName(), annotation); 054 055 FieldConduit<Object> conduit = createConduit(field, blockId); 056 057 field.setConduit(conduit); 058 059 return true; // claim the field 060 } 061 062 private FieldConduit<Object> createConduit(PlasticField field, final String blockId) 063 { 064 final String className = field.getPlasticClass().getClassName(); 065 final String fieldName = field.getName(); 066 067 return new ReadOnlyComponentFieldConduit(className, fieldName) 068 { 069 public Object get(Object instance, InstanceContext context) 070 { 071 ComponentResources resources = context.get(ComponentResources.class); 072 073 return resources.getBlock(blockId); 074 } 075 }; 076 } 077 078 private String getBlockId(String fieldName, Id annotation) 079 { 080 return annotation != null ? annotation.value() : InternalUtils.stripMemberName(fieldName); 081 } 082}