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1 /*
2 * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0.1/httpcore/src/main/java/org/apache/http/params/DefaultedHttpParams.java $
3 * $Revision: 744530 $
4 * $Date: 2009-02-14 18:09:27 +0100 (Sat, 14 Feb 2009) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements. See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership. The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License. You may obtain a copy of the License at
14 *
15 * http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied. See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation. For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32 package org.apache.http.params;
33
34 import org.apache.http.params.HttpParams;
35
36 /**
37 * {@link HttpParams} implementation that delegates resolution of a parameter
38 * to the given default {@link HttpParams} instance if the parameter is not
39 * present in the local one. The state of the local collection can be mutated,
40 * whereas the default collection is treated as read-only.
41 *
42 *
43 * @version $Revision: 744530 $
44 *
45 * @since 4.0
46 */
47 public final class DefaultedHttpParams extends AbstractHttpParams {
48
49 private final HttpParams local;
50 private final HttpParams defaults;
51
52 public DefaultedHttpParams(final HttpParams local, final HttpParams defaults) {
53 super();
54 if (local == null) {
55 throw new IllegalArgumentException("HTTP parameters may not be null");
56 }
57 this.local = local;
58 this.defaults = defaults;
59 }
60
61 /**
62 * Creates a copy of the local collection with the same default
63 */
64 public HttpParams copy() {
65 HttpParams clone = this.local.copy();
66 return new DefaultedHttpParams(clone, this.defaults);
67 }
68
69 /**
70 * Retrieves the value of the parameter from the local collection and, if the
71 * parameter is not set locally, delegates its resolution to the default
72 * collection.
73 */
74 public Object getParameter(final String name) {
75 Object obj = this.local.getParameter(name);
76 if (obj == null && this.defaults != null) {
77 obj = this.defaults.getParameter(name);
78 }
79 return obj;
80 }
81
82 /**
83 * Attempts to remove the parameter from the local collection. This method
84 * <i>does not</i> modify the default collection.
85 */
86 public boolean removeParameter(final String name) {
87 return this.local.removeParameter(name);
88 }
89
90 /**
91 * Sets the parameter in the local collection. This method <i>does not</i>
92 * modify the default collection.
93 */
94 public HttpParams setParameter(final String name, final Object value) {
95 return this.local.setParameter(name, value);
96 }
97
98 public HttpParams getDefaults() {
99 return this.defaults;
100 }
101
102 }