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
        // "exec-and-wait" interceptor
        this.request = request;
        this.session = request.getSession(false);
}

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.

Parameters:

request - the http servlet request object.

 public  void clear() 
{
        if (session == null ) {
            return;
        }
        synchronized (session) {
            entries = null;
            Enumeration< String > attributeNamesEnum = session.getAttributeNames();
            while(attributeNamesEnum.hasMoreElements()) {
                session.removeAttribute(attributeNamesEnum.nextElement());
            }
        }
}

Removes all attributes from the session as well as clears entries in this map.

 public Set entrySet() 
{
        if (session == null) {
            return Collections.EMPTY_SET;
        }
        synchronized (session) {
            if (entries == null) {
                entries = new HashSet< Object >();
                Enumeration enumeration = session.getAttributeNames();
                while (enumeration.hasMoreElements()) {
                    final String key = enumeration.nextElement().toString();
                    final Object value = session.getAttribute(key);
                    entries.add(new Map.Entry() {
                        public boolean equals(Object obj) {
                            Map.Entry entry = (Map.Entry) 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 Object getKey() {
                            return key;
                        }
                        public Object getValue() {
                            return value;
                        }
                        public Object setValue(Object obj) {
                            session.setAttribute(key.toString(), obj);
                            return value;
                        }
                    });
                }
            }
        }
        return entries;
}

Returns a Set of attributes from the http session.

 public Object get(Object key) 
{
        if (session == null) {
            return null;
        }
        synchronized (session) {
            return session.getAttribute(key.toString());
        }
}

Returns the session attribute associated with the given key or null if it doesn't exist.

 public  void invalidate() 
{
        if (session == null) {
            return;
        }
        synchronized (session) {
            session.invalidate();
            session = null;
            entries = null;
        }
}

Invalidate the http session.

 public Object put(Object key,
    Object value) 
{
        synchronized (this) {
            if (session == null) {
                session = request.getSession(true);
            }
        }
        synchronized (session) {
            entries = null;
            session.setAttribute(key.toString(), value);
            return get(key);
        }
}

Saves an attribute in the session.

 public Object remove(Object key) 
{
        if (session == null) {
            return null;
        }
        synchronized (session) {
            entries = null;
            Object value = get(key);
            session.removeAttribute(key.toString());
            return value;
        }
}

Removes the specified session attribute.