001/*
002 * Copyright 2002-2018 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 org.springframework.aop.framework.AopConfigException;
020import org.springframework.core.Ordered;
021import org.springframework.util.Assert;
022
023/**
024 * Implementation of {@link AspectInstanceFactory} that creates a new instance
025 * of the specified aspect class for every {@link #getAspectInstance()} call.
026 *
027 * @author Juergen Hoeller
028 * @since 2.0.4
029 */
030public class SimpleAspectInstanceFactory implements AspectInstanceFactory {
031
032        private final Class<?> aspectClass;
033
034
035        /**
036         * Create a new SimpleAspectInstanceFactory for the given aspect class.
037         * @param aspectClass the aspect class
038         */
039        public SimpleAspectInstanceFactory(Class<?> aspectClass) {
040                Assert.notNull(aspectClass, "Aspect class must not be null");
041                this.aspectClass = aspectClass;
042        }
043
044
045        /**
046         * Return the specified aspect class (never {@code null}).
047         */
048        public final Class<?> getAspectClass() {
049                return this.aspectClass;
050        }
051
052        @Override
053        public final Object getAspectInstance() {
054                try {
055                        return this.aspectClass.newInstance();
056                }
057                catch (InstantiationException ex) {
058                        throw new AopConfigException(
059                                        "Unable to instantiate aspect class: " + this.aspectClass.getName(), ex);
060                }
061                catch (IllegalAccessException ex) {
062                        throw new AopConfigException(
063                                        "Could not access aspect constructor: " + this.aspectClass.getName(), ex);
064                }
065        }
066
067        @Override
068        public ClassLoader getAspectClassLoader() {
069                return this.aspectClass.getClassLoader();
070        }
071
072        /**
073         * Determine the order for this factory's aspect instance,
074         * either an instance-specific order expressed through implementing
075         * the {@link org.springframework.core.Ordered} interface,
076         * or a fallback order.
077         * @see org.springframework.core.Ordered
078         * @see #getOrderForAspectClass
079         */
080        @Override
081        public int getOrder() {
082                return getOrderForAspectClass(this.aspectClass);
083        }
084
085        /**
086         * Determine a fallback order for the case that the aspect instance
087         * does not express an instance-specific order through implementing
088         * the {@link org.springframework.core.Ordered} interface.
089         * <p>The default implementation simply returns {@code Ordered.LOWEST_PRECEDENCE}.
090         * @param aspectClass the aspect class
091         */
092        protected int getOrderForAspectClass(Class<?> aspectClass) {
093                return Ordered.LOWEST_PRECEDENCE;
094        }
095
096}