org.apache.mina.core.session.IoSessionAttributeMap Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.mina.core.session;
import java.util.Set;
/**
* Stores the user-defined attributes which is provided per {@link IoSession}.
* All user-defined attribute accesses in {@link IoSession} are forwarded to
* the instance of {@link IoSessionAttributeMap}.
*
* @author Apache MINA Project
*/
public interface IoSessionAttributeMap {
/**
* @return the value of user defined attribute associated with the
* specified key. If there's no such attribute, the specified default
* value is associated with the specified key, and the default value is
* returned. This method is same with the following code except that the
* operation is performed atomically.
*
* if (containsAttribute(key)) {
* return getAttribute(key);
* } else {
* setAttribute(key, defaultValue);
* return defaultValue;
* }
*
*
* @param session the session for which we want to get an attribute
* @param key The key we are looking for
* @param defaultValue The default returned value if the attribute is not found
*/
Object getAttribute(IoSession session, Object key, Object defaultValue);
/**
* Sets a user-defined attribute.
*
* @param session the session for which we want to set an attribute
* @param key the key of the attribute
* @param value the value of the attribute
* @return The old value of the attribute. null if it is new.
*/
Object setAttribute(IoSession session, Object key, Object value);
/**
* Sets a user defined attribute if the attribute with the specified key
* is not set yet. This method is same with the following code except
* that the operation is performed atomically.
*
* if (containsAttribute(key)) {
* return getAttribute(key);
* } else {
* return setAttribute(key, value);
* }
*
*
* @param session the session for which we want to set an attribute
* @param key The key we are looking for
* @param value The value to inject
* @return The previous attribute
*/
Object setAttributeIfAbsent(IoSession session, Object key, Object value);
/**
* Removes a user-defined attribute with the specified key.
*
* @return The old value of the attribute. null if not found.
* @param session the session for which we want to remove an attribute
* @param key The key we are looking for
*/
Object removeAttribute(IoSession session, Object key);
/**
* Removes a user defined attribute with the specified key if the current
* attribute value is equal to the specified value. This method is same
* with the following code except that the operation is performed
* atomically.
*
* if (containsAttribute(key) && getAttribute(key).equals(value)) {
* removeAttribute(key);
* return true;
* } else {
* return false;
* }
*
*
* @param session the session for which we want to remove a value
* @param key The key we are looking for
* @param value The value to remove
* @return true if the value has been removed, false if the key was
* not found of the value not removed
*/
boolean removeAttribute(IoSession session, Object key, Object value);
/**
* Replaces a user defined attribute with the specified key if the
* value of the attribute is equals to the specified old value.
* This method is same with the following code except that the operation
* is performed atomically.
*
* if (containsAttribute(key) && getAttribute(key).equals(oldValue)) {
* setAttribute(key, newValue);
* return true;
* } else {
* return false;
* }
*
*
* @param session the session for which we want to replace an attribute
* @param key The key we are looking for
* @param oldValue The old value to replace
* @param newValue The new value to set
* @return true if the value has been replaced, false if the key was
* not found of the value not replaced
*/
boolean replaceAttribute(IoSession session, Object key, Object oldValue, Object newValue);
/**
* @return true if this session contains the attribute with
* the specified key.
*
* @param session the session for which wa want to check if an attribute is present
* @param key The key we are looking for
*/
boolean containsAttribute(IoSession session, Object key);
/**
* @return the set of keys of all user-defined attributes.
*
* @param session the session for which we want the set of attributes
*/
Set