001// Copyright 2004, 2005 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.tapestry.enhance; 016 017import java.lang.reflect.Modifier; 018 019import org.apache.hivemind.ApplicationRuntimeException; 020import org.apache.hivemind.Location; 021import org.apache.hivemind.service.MethodSignature; 022import org.apache.hivemind.util.Defense; 023import org.apache.tapestry.services.InjectedValueProvider; 024import org.apache.tapestry.spec.InjectSpecification; 025 026/** 027 * Implementation for injection type "object" (the default). Adds read-only properties to the 028 * enhanced class that contain objects injected from HiveMind. 029 * 030 * @author Howard M. Lewis Ship 031 * @since 4.0 032 */ 033public class InjectObjectWorker implements InjectEnhancementWorker 034{ 035 private InjectedValueProvider _provider; 036 037 public void performEnhancement(EnhancementOperation op, InjectSpecification is) 038 { 039 String name = is.getProperty(); 040 String objectReference = is.getObject(); 041 Location location = is.getLocation(); 042 043 injectObject(op, objectReference, name, location); 044 } 045 046 public void injectObject(EnhancementOperation op, String objectReference, String propertyName, 047 Location location) 048 { 049 Defense.notNull(op, "op"); 050 Defense.notNull(propertyName, "propertyName"); 051 Defense.notNull(objectReference, "objectReference"); 052 053 Class propertyType = op.getPropertyType(propertyName); 054 if (propertyType == null) 055 propertyType = Object.class; 056 057 op.claimReadonlyProperty(propertyName); 058 059 Object injectedValue = _provider.obtainValue(objectReference, location); 060 061 if (injectedValue == null) 062 throw new ApplicationRuntimeException(EnhanceMessages 063 .locatedValueIsNull(objectReference), location, null); 064 065 if (!propertyType.isAssignableFrom(injectedValue.getClass())) 066 throw new ApplicationRuntimeException(EnhanceMessages.incompatibleInjectType( 067 objectReference, 068 injectedValue, 069 propertyType), location, null); 070 071 String fieldName = op.addInjectedField("_$" + propertyName, propertyType, injectedValue); 072 073 String methodName = EnhanceUtils.createAccessorMethodName(propertyName); 074 075 op.addMethod( 076 Modifier.PUBLIC, 077 new MethodSignature(propertyType, methodName, null, null), 078 "return " + fieldName + ";", location); 079 } 080 081 public void setProvider(InjectedValueProvider provider) 082 { 083 _provider = provider; 084 } 085}