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Tools to assist in the reading of configuration/preferences files in various formats

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *     http://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.apache.commons.configuration2.tree;

/**
 * 
 * An interface for matching nodes based on specific criteria.
 * 
 * 
 * This interface is used by {@link NodeHandler} to support advanced filtering on the child nodes of a given parent
 * node. This is useful for instance for special {@link ExpressionEngine} implementations which do no direct or strict
 * matches based on node names. An example could be an expression engine that treats the passed in node keys in a
 * case-insensitive manner. Such an engine would use a special case-insensitive matcher when resolving configuration
 * keys.
 * 
 * 
 * The idea behind this interface is that a matcher has to match a property of a node against a given criterion. This
 * criterion is passed to the matching function so that matchers can be implemented in a state-less fashion and shared
 * between multiple components.
 * 
 *
 * @since 2.0
 * @param  the type of the criterion evaluated by this matcher
 */
public interface NodeMatcher {
    /**
     * Tests whether the passed in node matches the given criterion.
     *
     * @param node the node to be tested
     * @param handler the corresponding {@code NodeHandler}
     * @param criterion the criterion to match against
     * @param  the type of the node
     * @return true if this node matches the criterion, false otherwise
     */
     boolean matches(T node, NodeHandler handler, C criterion);
}