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.discovery.resource.names;
18
19 import org.apache.commons.discovery.ResourceNameDiscover;
20 import org.apache.commons.discovery.ResourceNameIterator;
21
22 /**
23 * Helper class for methods implementing the ResourceNameDiscover interface.
24 */
25 public abstract class ResourceNameDiscoverImpl implements ResourceNameDiscover {
26
27 /**
28 * Locate names of resources that are bound to {@code resourceName}.
29 *
30 * @param resourceName The resource name to locate
31 * @return A new {@link ResourceNameIterator}
32 */
33 public abstract ResourceNameIterator findResourceNames(String resourceName);
34
35 /**
36 * Locate names of resources that are bound to {@code inputNames}.
37 *
38 * @param inputNames The resource names to locate
39 * @return A new {@link ResourceNameIterator}
40 */
41 public ResourceNameIterator findResourceNames(final ResourceNameIterator inputNames) {
42 return new ResourceNameIterator() {
43
44 private ResourceNameIterator resourceNames = null;
45
46 private String resourceName = null;
47
48 public boolean hasNext() {
49 if (resourceName == null) {
50 resourceName = getNextResourceName();
51 }
52 return resourceName != null;
53 }
54
55 public String nextResourceName() {
56 String name = resourceName;
57 resourceName = null;
58 return name;
59 }
60
61 private String getNextResourceName() {
62 while (inputNames.hasNext() && (resourceNames == null || !resourceNames.hasNext())) {
63 resourceNames =
64 findResourceNames(inputNames.nextResourceName());
65 }
66
67 return (resourceNames != null && resourceNames.hasNext())
68 ? resourceNames.nextResourceName()
69 : null;
70 }
71 };
72 }
73
74 }