001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.configuration2.tree;
018
019/**
020 * <p>
021 * An interface for matching nodes based on specific criteria.
022 * </p>
023 * <p>
024 * This interface is used by {@link NodeHandler} to support advanced filtering
025 * on the child nodes of a given parent node. This is useful for instance for
026 * special {@link ExpressionEngine} implementations which do no direct or strict
027 * matches based on node names. An example could be an expression engine that
028 * treats the passed in node keys in a case-insensitive manner. Such an engine
029 * would use a special case-insensitive matcher when resolving configuration
030 * keys.
031 * </p>
032 * <p>
033 * The idea behind this interface is that a matcher has to match a property of a
034 * node against a given criterion. This criterion is passed to the matching
035 * function so that matchers can be implemented in a state-less fashion and
036 * shared between multiple components.
037 * </p>
038 *
039 * @since 2.0
040 * @param <C> the type of the criterion evaluated by this matcher
041 */
042public interface NodeMatcher<C>
043{
044    /**
045     * Tests whether the passed in node matches the given criterion.
046     *
047     * @param node the node to be tested
048     * @param handler the corresponding {@code NodeHandler}
049     * @param criterion the criterion to match against
050     * @param <T> the type of the node
051     * @return <b>true</b> if this node matches the criterion, <b>false</b>
052     *         otherwise
053     */
054    <T> boolean matches(T node, NodeHandler<T> handler, C criterion);
055}