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. 014 015 package org.apache.tapestry.enhance; 016 017 import java.lang.reflect.Modifier; 018 019 import org.apache.hivemind.ApplicationRuntimeException; 020 import org.apache.hivemind.Location; 021 import org.apache.hivemind.service.MethodSignature; 022 import org.apache.hivemind.util.Defense; 023 import org.apache.tapestry.services.InjectedValueProvider; 024 import 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 */ 033 public 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 }