/*
* $Id: SessionMap.java 911398 2010-02-18 13:45:08Z lukaszlenart $
*
* 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.struts2.dispatcher;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* A simple implementation of the {@link java.util.Map} interface to handle a collection of HTTP session
* attributes. The {@link #entrySet()} method enumerates over all session attributes and creates a Set of entries.
* Note, this will occur lazily - only when the entry set is asked for.
*/
public class SessionMap<K, V> extends AbstractMap<K, V> implements Serializable {
private static final long serialVersionUID = 4678843241638046854L;
protected HttpSession session;
protected Set<Map.Entry<K, V>> entries;
protected HttpServletRequest request;
/**
* Creates a new session map given a http servlet request. Note, ths enumeration of request
* attributes will occur when the map entries are asked for.
*
* @param request the http servlet request object.
*/
public SessionMap(HttpServletRequest request) {
// note, holding on to this request and relying on lazy session initalization will not work
// if you are running your action invocation in a background task, such as using the
// "execAndWait" interceptor
this.request = request;
this.session = request.getSession(false);
}
/**
* Invalidate the http session.
*/
public void invalidate() {
if (session == null) {
return;
}
synchronized (session) {
session.invalidate();
session = null;
entries = null;
}
}
/**
* Removes all attributes from the session as well as clears entries in this
* map.
*/
public void clear() {
if (session == null) {
return;
}
synchronized (session) {
entries = null;
Enumeration<String> attributeNamesEnum = session.getAttributeNames();
while (attributeNamesEnum.hasMoreElements()) {
session.removeAttribute(attributeNamesEnum.nextElement());
}
}
}
/**
* Returns a Set of attributes from the http session.
*
* @return a Set of attributes from the http session.
*/
public Set<java.util.Map.Entry<K, V>> entrySet() {
if (session == null) {
return Collections.emptySet();
}
synchronized (session) {
if (entries == null) {
entries = new HashSet<Map.Entry<K, V>>();
Enumeration<? extends Object> enumeration = session.getAttributeNames();
while (enumeration.hasMoreElements()) {
final String key = enumeration.nextElement().toString();
final Object value = session.getAttribute(key);
entries.add(new Map.Entry<K, V>() {
public boolean equals(Object obj) {
if (!(obj instanceof Map.Entry)) {
return false;
}
Map.Entry<K, V> entry = (Map.Entry<K, V>) obj;
return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
}
public int hashCode() {
return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
}
public K getKey() {
return (K) key;
}
public V getValue() {
return (V) value;
}
public V setValue(Object obj) {
session.setAttribute(key, obj);
return (V) value;
}
});
}
}
}
return entries;
}
/**
* Returns the session attribute associated with the given key or <tt>null</tt> if it doesn't exist.
*
* @param key the name of the session attribute.
* @return the session attribute or <tt>null</tt> if it doesn't exist.
*/
public V get(Object key) {
if (session == null) {
return null;
}
synchronized (session) {
return (V) session.getAttribute(key.toString());
}
}
/**
* Saves an attribute in the session.
*
* @param key the name of the session attribute.
* @param value the value to set.
* @return the object that was just set.
*/
public V put(K key, V value) {
synchronized (this) {
if (session == null) {
session = request.getSession(true);
}
}
synchronized (session) {
V oldValue = get(key);
entries = null;
session.setAttribute(key.toString(), value);
return oldValue;
}
}
/**
* Removes the specified session attribute.
*
* @param key the name of the attribute to remove.
* @return the value that was removed or <tt>null</tt> if the value was not found (and hence, not removed).
*/
public V remove(Object key) {
if (session == null) {
return null;
}
synchronized (session) {
entries = null;
V value = get(key);
session.removeAttribute(key.toString());
return value;
}
}
/**
* Checks if the specified session attribute with the given key exists.
*
* @param key the name of the session attribute.
* @return <tt>true</tt> if the session attribute exits or <tt>false</tt> if it doesn't exist.
*/
public boolean containsKey(Object key) {
if (session == null) {
return false;
}
synchronized (session) {
return (session.getAttribute(key.toString()) != null);
}
}
}
|