001/* 002 * Copyright 2002-2015 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.aop.aspectj; 018 019import java.io.Serializable; 020 021import org.springframework.core.Ordered; 022import org.springframework.util.Assert; 023 024/** 025 * Implementation of {@link AspectInstanceFactory} that is backed by a 026 * specified singleton object, returning the same instance for every 027 * {@link #getAspectInstance()} call. 028 * 029 * @author Rod Johnson 030 * @author Juergen Hoeller 031 * @since 2.0 032 * @see SimpleAspectInstanceFactory 033 */ 034@SuppressWarnings("serial") 035public class SingletonAspectInstanceFactory implements AspectInstanceFactory, Serializable { 036 037 private final Object aspectInstance; 038 039 040 /** 041 * Create a new SingletonAspectInstanceFactory for the given aspect instance. 042 * @param aspectInstance the singleton aspect instance 043 */ 044 public SingletonAspectInstanceFactory(Object aspectInstance) { 045 Assert.notNull(aspectInstance, "Aspect instance must not be null"); 046 this.aspectInstance = aspectInstance; 047 } 048 049 050 @Override 051 public final Object getAspectInstance() { 052 return this.aspectInstance; 053 } 054 055 @Override 056 public ClassLoader getAspectClassLoader() { 057 return this.aspectInstance.getClass().getClassLoader(); 058 } 059 060 /** 061 * Determine the order for this factory's aspect instance, 062 * either an instance-specific order expressed through implementing 063 * the {@link org.springframework.core.Ordered} interface, 064 * or a fallback order. 065 * @see org.springframework.core.Ordered 066 * @see #getOrderForAspectClass 067 */ 068 @Override 069 public int getOrder() { 070 if (this.aspectInstance instanceof Ordered) { 071 return ((Ordered) this.aspectInstance).getOrder(); 072 } 073 return getOrderForAspectClass(this.aspectInstance.getClass()); 074 } 075 076 /** 077 * Determine a fallback order for the case that the aspect instance 078 * does not express an instance-specific order through implementing 079 * the {@link org.springframework.core.Ordered} interface. 080 * <p>The default implementation simply returns {@code Ordered.LOWEST_PRECEDENCE}. 081 * @param aspectClass the aspect class 082 */ 083 protected int getOrderForAspectClass(Class<?> aspectClass) { 084 return Ordered.LOWEST_PRECEDENCE; 085 } 086 087}