1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.configuration2.tree; 18 19 /** 20 * <p> 21 * An interface for matching nodes based on specific criteria. 22 * </p> 23 * <p> 24 * This interface is used by {@link NodeHandler} to support advanced filtering on the child nodes of a given parent 25 * node. This is useful for instance for special {@link ExpressionEngine} implementations which do no direct or strict 26 * matches based on node names. An example could be an expression engine that treats the passed in node keys in a 27 * case-insensitive manner. Such an engine would use a special case-insensitive matcher when resolving configuration 28 * keys. 29 * </p> 30 * <p> 31 * The idea behind this interface is that a matcher has to match a property of a node against a given criterion. This 32 * criterion is passed to the matching function so that matchers can be implemented in a state-less fashion and shared 33 * between multiple components. 34 * </p> 35 * 36 * @since 2.0 37 * @param <C> the type of the criterion evaluated by this matcher 38 */ 39 public interface NodeMatcher<C> { 40 /** 41 * Tests whether the passed in node matches the given criterion. 42 * 43 * @param node the node to be tested 44 * @param handler the corresponding {@code NodeHandler} 45 * @param criterion the criterion to match against 46 * @param <T> the type of the node 47 * @return <b>true</b> if this node matches the criterion, <b>false</b> otherwise 48 */ 49 <T> boolean matches(T node, NodeHandler<T> handler, C criterion); 50 }