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.jnet;
18
19 import java.net.URLStreamHandler;
20 import java.net.URLStreamHandlerFactory;
21
22 /**
23 * A parent aware url stream handler factory delegates to a parent
24 * url stream handler factory,
25 */
26 public abstract class ParentAwareURLStreamHandlerFactory implements URLStreamHandlerFactory {
27
28 protected URLStreamHandlerFactory parentFactory;
29
30 /**
31 * Set the parent factory.
32 * @param factory
33 */
34 public void setParentFactory(URLStreamHandlerFactory factory) {
35 this.parentFactory = factory;
36 }
37
38 /**
39 * Return the parent factory.
40 * @return The parent factory.
41 */
42 public URLStreamHandlerFactory getParent() {
43 return this.parentFactory;
44 }
45
46 /**
47 * @see java.net.URLStreamHandlerFactory#createURLStreamHandler(java.lang.String)
48 */
49 public URLStreamHandler createURLStreamHandler(String protocol) {
50 URLStreamHandler handler = this.create(protocol);
51 if ( handler == null && this.parentFactory != null ) {
52 handler = this.parentFactory.createURLStreamHandler(protocol);
53 }
54 return handler;
55 }
56
57 /**
58 * This method can be overwritten by subclasses to instantiate url stream
59 * handlers for the given protocol.
60 * @param protocol The protocol.
61 * @return A url stream handler for the protocol or null.
62 */
63 protected abstract URLStreamHandler create(String protocol);
64 }