1 /* 2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/params/DefaultedHttpParams.java $ 3 * $Revision: 610763 $ 4 * $Date: 2008-01-10 04:01:13 -0800 (Thu, 10 Jan 2008) $ 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 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a> 43 * 44 * @version $Revision: 610763 $ 45 */ 46 public final class DefaultedHttpParams extends AbstractHttpParams { 47 48 private final HttpParams local; 49 private final HttpParams defaults; 50 DefaultedHttpParams(final HttpParams local, final HttpParams defaults)51 public DefaultedHttpParams(final HttpParams local, final HttpParams defaults) { 52 super(); 53 if (local == null) { 54 throw new IllegalArgumentException("HTTP parameters may not be null"); 55 } 56 this.local = local; 57 this.defaults = defaults; 58 } 59 60 /** 61 * Creates a copy of the local collection with the same default 62 */ copy()63 public HttpParams copy() { 64 HttpParams clone = this.local.copy(); 65 return new DefaultedHttpParams(clone, this.defaults); 66 } 67 68 /** 69 * Retrieves the value of the parameter from the local collection and, if the 70 * parameter is not set locally, delegates its resolution to the default 71 * collection. 72 */ getParameter(final String name)73 public Object getParameter(final String name) { 74 Object obj = this.local.getParameter(name); 75 if (obj == null && this.defaults != null) { 76 obj = this.defaults.getParameter(name); 77 } 78 return obj; 79 } 80 81 /** 82 * Attempts to remove the parameter from the local collection. This method 83 * <i>does not</i> modify the default collection. 84 */ removeParameter(final String name)85 public boolean removeParameter(final String name) { 86 return this.local.removeParameter(name); 87 } 88 89 /** 90 * Sets the parameter in the local collection. This method <i>does not</i> 91 * modify the default collection. 92 */ setParameter(final String name, final Object value)93 public HttpParams setParameter(final String name, final Object value) { 94 return this.local.setParameter(name, value); 95 } 96 getDefaults()97 public HttpParams getDefaults() { 98 return this.defaults; 99 } 100 101 } 102