1 /* 2 * Copyright 2002-2009 the original author or authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.springframework.aop.aspectj.annotation; 18 19 import org.springframework.util.Assert; 20 21 /** 22 * Decorator to cause a {@link MetadataAwareAspectInstanceFactory} to instantiate only once. 23 * 24 * @author Rod Johnson 25 * @author Juergen Hoeller 26 * @since 2.0 27 */ 28 public class LazySingletonAspectInstanceFactoryDecorator implements MetadataAwareAspectInstanceFactory { 29 30 private final MetadataAwareAspectInstanceFactory maaif; 31 32 private volatile Object materialized; 33 34 35 /** 36 * Create a new lazily initializing decorator for the given AspectInstanceFactory. 37 * @param maaif the MetadataAwareAspectInstanceFactory to decorate 38 */ LazySingletonAspectInstanceFactoryDecorator(MetadataAwareAspectInstanceFactory maaif)39 public LazySingletonAspectInstanceFactoryDecorator(MetadataAwareAspectInstanceFactory maaif) { 40 Assert.notNull(maaif, "AspectInstanceFactory must not be null"); 41 this.maaif = maaif; 42 } 43 44 getAspectInstance()45 public synchronized Object getAspectInstance() { 46 if (this.materialized == null) { 47 synchronized (this) { 48 if (this.materialized == null) { 49 this.materialized = this.maaif.getAspectInstance(); 50 } 51 } 52 } 53 return this.materialized; 54 } 55 isMaterialized()56 public boolean isMaterialized() { 57 return (this.materialized != null); 58 } 59 getAspectClassLoader()60 public ClassLoader getAspectClassLoader() { 61 return this.maaif.getAspectClassLoader(); 62 } 63 getAspectMetadata()64 public AspectMetadata getAspectMetadata() { 65 return this.maaif.getAspectMetadata(); 66 } 67 getOrder()68 public int getOrder() { 69 return this.maaif.getOrder(); 70 } 71 72 73 @Override toString()74 public String toString() { 75 return "LazySingletonAspectInstanceFactoryDecorator: decorating " + this.maaif; 76 } 77 78 } 79