    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}