javaxt.http.servlet.HttpSession Maven / Gradle / Ivy

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package javaxt.http.servlet;

import java.util.Enumeration;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.http.HttpSessionContext;

//******************************************************************************
//**  HttpSession
//******************************************************************************
/**
 * Provides a way to identify a user and store information about the user across
 * multiple page requests/visits.
 *
 * Note that this server uses cookies to manage sessions.
 *
 ******************************************************************************/

public class HttpSession implements javax.servlet.http.HttpSession {

	private static final ConcurrentHashMap sessions = new ConcurrentHashMap();

	private static final ConcurrentHashMap map = new ConcurrentHashMap();

	private String sessionID;
	private long lastAccessTime = -1;
	private long creationTime;

	// **************************************************************************
	// ** Constructor
	// **************************************************************************
	/**
	 * Creates a new session and adds it to the list of active sessions.
	 */
	protected HttpSession() {

		// Create new session and add it to the list of active sessions
		while (true) {
			sessionID = CreateID(28);
			synchronized (sessions) {
				if (sessions.get(sessionID) == null) {
					creationTime = new java.util.Date().getTime();
					sessions.put(sessionID, this);
					sessions.notifyAll();
					break;
				}
			}
		}

		// TODO: Create timer task to periodically clean up old sessions

	}

	// **************************************************************************
	// ** getServletContext
	// **************************************************************************
	/**
	 * Returns the ServletContext.
	 */
	@Override
	public ServletContext getServletContext() {
		return HttpServlet.context;
	}

	// **************************************************************************
	// ** getID
	// **************************************************************************
	/**
	 * Returns a string containing the unique identifier assigned to this
	 * session.
	 */
	public String getID() {
		return sessionID;
	}

	// **************************************************************************
	// ** getCreationTime
	// **************************************************************************
	/**
	 * Returns the time when this session was created, measured in milliseconds
	 * since midnight January 1, 1970 GMT.
	 */
	@Override
	public long getCreationTime() {
		return creationTime;
	}

	// **************************************************************************
	// ** getLastAccessedTime
	// **************************************************************************
	/**
	 * Returns the time when this session was last accessed, measured in
	 * milliseconds since midnight January 1, 1970 GMT.
	 */
	@Override
	public long getLastAccessedTime() {
		return lastAccessTime;
	}

	// **************************************************************************
	// ** isNew
	// **************************************************************************
	/**
	 * Returns true if the client does not yet know about the session or if the
	 * server has not accessed the session.
	 */
	@Override
	public boolean isNew() {
		return lastAccessTime < 0;
	}

	// **************************************************************************
	// ** getAttribute
	// **************************************************************************
	/**
	 * Returns the object bound with the specified name in this session, or null
	 * if no object is bound under the name.
	 */
	@Override
	public Object getAttribute(String name) {
		Object val = null;
		synchronized (map) {
			val = map.get(name);
		}
		return val;
	}

	// **************************************************************************
	// ** setAttribute
	// **************************************************************************
	/**
	 * Binds an object to this session, using the name specified.
	 */
	@Override
	public void setAttribute(String name, Object value) {
		synchronized (map) {
			map.put(name, value);
			map.notifyAll();
		}
	}

	// **************************************************************************
	// ** removeAttribute
	// **************************************************************************
	/** Removes the attribute with the given name from the servlet context. */
	@Override
	public void removeAttribute(String name) {
		synchronized (map) {
			map.remove(name);
			map.notifyAll();
		}
	}

	// **************************************************************************
	// ** invalidate
	// **************************************************************************
	/**
	 * Invalidates this session then unbinds any objects bound to it.
	 */
	@Override
	public void invalidate() {
		synchronized (sessions) {
			sessions.remove(sessionID);
			sessions.notifyAll();
		}
		synchronized (map) {
			map.clear();
			map.notifyAll();
		}
	}

	/** Returns a session associated with a given session ID. */
	protected static final HttpSession get(String sessionID) {
		HttpSession session;
		synchronized (sessions) {
			session = sessions.get(sessionID);
			if (session != null)
				session.lastAccessTime = new java.util.Date().getTime();
		}
		return session;
	}

	/** Generates a random sequence of alpha-numeric characters. */
	private static final String CreateID(int len) {
		StringBuffer str = new StringBuffer(len);
		final String strValid = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
		for (int i = 1; i <= len; i++) {
			int x = new java.util.Random().nextInt(strValid.length());
			str.append(strValid.substring(x, x + 1));
		}
		return str.toString();
	}

	@Override
	public String toString() {
		return getID();
	}

	@Override
	public String getId() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void setMaxInactiveInterval(int interval) {
		// TODO Auto-generated method stub

	}

	@Override
	public int getMaxInactiveInterval() {
		// TODO Auto-generated method stub
		return 0;
	}

	@Override
	public HttpSessionContext getSessionContext() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Object getValue(String name) {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public Enumeration getAttributeNames() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public String[] getValueNames() {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void putValue(String name, Object value) {
		// TODO Auto-generated method stub

	}

	@Override
	public void removeValue(String name) {
		// TODO Auto-generated method stub

	}
}