1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 * 19 */ 20 package org.apache.mina.filter.util; 21 22 import java.util.Map; 23 import java.util.Set; 24 import java.util.concurrent.ConcurrentHashMap; 25 26 import org.apache.mina.core.filterchain.IoFilter; 27 import org.apache.mina.core.filterchain.IoFilterAdapter; 28 import org.apache.mina.core.session.IoSession; 29 30 /** 31 * An {@link IoFilter} that sets initial attributes when a new 32 * {@link IoSession} is created. By default, the attribute map is empty when 33 * an {@link IoSession} is newly created. Inserting this filter will make 34 * the pre-configured attributes available after this filter executes the 35 * <tt>sessionCreated</tt> event. 36 * 37 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 38 * @org.apache.xbean.XBean 39 */ 40 public class SessionAttributeInitializingFilter extends IoFilterAdapter { 41 private final Map<String, Object> attributes = new ConcurrentHashMap<String, Object>(); 42 43 /** 44 * Creates a new instance with no default attributes. You can set 45 * the additional attributes by calling methods such as 46 * {@link #setAttribute(String, Object)} and {@link #setAttributes(Map)}. 47 */ 48 public SessionAttributeInitializingFilter() { 49 // Do nothing 50 } 51 52 /** 53 * Creates a new instance with the specified default attributes. You can 54 * set the additional attributes by calling methods such as 55 * {@link #setAttribute(String, Object)} and {@link #setAttributes(Map)}. 56 */ 57 public SessionAttributeInitializingFilter(Map<String, ? extends Object> attributes) { 58 setAttributes(attributes); 59 } 60 61 /** 62 * Returns the value of user-defined attribute. 63 * 64 * @param key the key of the attribute 65 * @return <tt>null</tt> if there is no attribute with the specified key 66 */ 67 public Object getAttribute(String key) { 68 return attributes.get(key); 69 } 70 71 /** 72 * Sets a user-defined attribute. 73 * 74 * @param key the key of the attribute 75 * @param value the value of the attribute 76 * @return The old value of the attribute. <tt>null</tt> if it is new. 77 */ 78 public Object setAttribute(String key, Object value) { 79 if (value == null) { 80 return removeAttribute(key); 81 } 82 83 return attributes.put(key, value); 84 } 85 86 /** 87 * Sets a user defined attribute without a value. This is useful when 88 * you just want to put a 'mark' attribute. Its value is set to 89 * {@link Boolean#TRUE}. 90 * 91 * @param key the key of the attribute 92 * @return The old value of the attribute. <tt>null</tt> if it is new. 93 */ 94 public Object setAttribute(String key) { 95 return attributes.put(key, Boolean.TRUE); 96 } 97 98 /** 99 * Removes a user-defined attribute with the specified key. 100 * 101 * @return The old value of the attribute. <tt>null</tt> if not found. 102 */ 103 public Object removeAttribute(String key) { 104 return attributes.remove(key); 105 } 106 107 /** 108 * Returns <tt>true</tt> if this session contains the attribute with 109 * the specified <tt>key</tt>. 110 */ 111 boolean containsAttribute(String key) { 112 return attributes.containsKey(key); 113 } 114 115 /** 116 * Returns the set of keys of all user-defined attributes. 117 */ 118 public Set<String> getAttributeKeys() { 119 return attributes.keySet(); 120 } 121 122 /** 123 * Sets the attribute map. The specified attributes are copied into the 124 * underlying map, so modifying the specified attributes parameter after 125 * the call won't change the internal state. 126 */ 127 public void setAttributes(Map<String, ? extends Object> attributes) { 128 if (attributes == null) { 129 attributes = new ConcurrentHashMap<String, Object>(); 130 } 131 132 this.attributes.clear(); 133 this.attributes.putAll(attributes); 134 } 135 136 /** 137 * Puts all pre-configured attributes into the actual session attribute 138 * map and forward the event to the next filter. 139 */ 140 @Override 141 public void sessionCreated(NextFilter nextFilter, IoSession session) throws Exception { 142 for (Map.Entry<String, Object> e : attributes.entrySet()) { 143 session.setAttribute(e.getKey(), e.getValue()); 144 } 145 146 nextFilter.sessionCreated(session); 147 } 148 }