Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.aop; import java.lang.reflect.Method; /** * Part of a {@link Pointcut}: Checks whether the target method is eligible for advice. * * <p>A MethodMatcher may be evaluated <b>statically</b> or at <b>runtime</b> (dynamically). * Static matching involves method and (possibly) method attributes. Dynamic matching * also makes arguments for a particular call available, and any effects of running * previous advice applying to the joinpoint. * * <p>If an implementation returns {@code false} from its {@link #isRuntime()} * method, evaluation can be performed statically, and the result will be the same * for all invocations of this method, whatever their arguments. This means that * if the {@link #isRuntime()} method returns {@code false}, the 3-arg * {@link #matches(java.lang.reflect.Method, Class, Object[])} method will never be invoked. * * <p>If an implementation returns {@code true} from its 2-arg * {@link #matches(java.lang.reflect.Method, Class)} method and its {@link #isRuntime()} method * returns {@code true}, the 3-arg {@link #matches(java.lang.reflect.Method, Class, Object[])} * method will be invoked <i>immediately before each potential execution of the related advice</i>, * to decide whether the advice should run. All previous advice, such as earlier interceptors * in an interceptor chain, will have run, so any state changes they have produced in * parameters or ThreadLocal state will be available at the time of evaluation. * * @author Rod Johnson * @since 11.11.2003 * @see Pointcut * @see ClassFilter */ public interface MethodMatcher { /** * Perform static checking whether the given method matches. * <p>If this returns {@code false} or if the {@link #isRuntime()} * method returns {@code false}, no runtime check (i.e. no * {@link #matches(java.lang.reflect.Method, Class, Object[])} call) * will be made. * @param method the candidate method * @param targetClass the target class * @return whether or not this method matches statically */ boolean matches(Method method, Class<?> targetClass); /** * Is this MethodMatcher dynamic, that is, must a final call be made on the * {@link #matches(java.lang.reflect.Method, Class, Object[])} method at * runtime even if the 2-arg matches method returns {@code true}? * <p>Can be invoked when an AOP proxy is created, and need not be invoked * again before each method invocation, * @return whether or not a runtime match via the 3-arg * {@link #matches(java.lang.reflect.Method, Class, Object[])} method * is required if static matching passed */ boolean isRuntime(); /** * Check whether there a runtime (dynamic) match for this method, * which must have matched statically. * <p>This method is invoked only if the 2-arg matches method returns * {@code true} for the given method and target class, and if the * {@link #isRuntime()} method returns {@code true}. Invoked * immediately before potential running of the advice, after any * advice earlier in the advice chain has run. * @param method the candidate method * @param targetClass the target class * @param args arguments to the method * @return whether there's a runtime match * @see MethodMatcher#matches(Method, Class) */ boolean matches(Method method, Class<?> targetClass, Object... args); /** * Canonical instance that matches all methods. */ MethodMatcher TRUE = TrueMethodMatcher.INSTANCE; }