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 on the child nodes of a given parent
025 * node. This is useful for instance for special {@link ExpressionEngine} implementations which do no direct or strict
026 * matches based on node names. An example could be an expression engine that treats the passed in node keys in a
027 * case-insensitive manner. Such an engine would use a special case-insensitive matcher when resolving configuration
028 * keys.
029 * </p>
030 * <p>
031 * The idea behind this interface is that a matcher has to match a property of a node against a given criterion. This
032 * criterion is passed to the matching function so that matchers can be implemented in a state-less fashion and shared
033 * between multiple components.
034 * </p>
035 *
036 * @since 2.0
037 * @param <C> the type of the criterion evaluated by this matcher
038 */
039public interface NodeMatcher<C> {
040    /**
041     * Tests whether the passed in node matches the given criterion.
042     *
043     * @param node the node to be tested
044     * @param handler the corresponding {@code NodeHandler}
045     * @param criterion the criterion to match against
046     * @param <T> the type of the node
047     * @return <b>true</b> if this node matches the criterion, <b>false</b> otherwise
048     */
049    <T> boolean matches(T node, NodeHandler<T> handler, C criterion);
050}