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 }