001/*
002 * Copyright 2002-2013 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.expression;
018
019import java.lang.reflect.Method;
020import java.util.List;
021
022/**
023 * MethodFilter instances allow SpEL users to fine tune the behaviour of the method
024 * resolution process. Method resolution (which translates from a method name in an
025 * expression to a real method to invoke) will normally retrieve candidate methods for
026 * invocation via a simple call to 'Class.getMethods()' and will choose the first one that
027 * is suitable for the input parameters. By registering a MethodFilter the user can
028 * receive a callback and change the methods that will be considered suitable.
029 *
030 * @author Andy Clement
031 * @since 3.0.1
032 */
033public interface MethodFilter {
034
035        /**
036         * Called by the method resolver to allow the SpEL user to organize the list of
037         * candidate methods that may be invoked. The filter can remove methods that should
038         * not be considered candidates and it may sort the results. The resolver will then
039         * search through the methods as returned from the filter when looking for a suitable
040         * candidate to invoke.
041         * @param methods the full list of methods the resolver was going to choose from
042         * @return a possible subset of input methods that may be sorted by order of relevance
043         */
044        List<Method> filter(List<Method> methods);
045
046}