HSQLDB example source code file (SessionManager.java)

This example HSQLDB source code file (SessionManager.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

hsqlexception, hsqlexception, intkeyhashmap, iterator, iterator, session, session, sessionmanager, user, user

The HSQLDB SessionManager.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */


package org.hsqldb;

import org.hsqldb.lib.IntKeyHashMap;
import org.hsqldb.lib.Iterator;
import org.hsqldb.SchemaManager.Schema;

/**
 * Container that maintains a map of session id's to Session objects.
 * Responsible for managing opening and closing of sessions.
 *
 * @author fredt@users
 * @version 1.8.0
 * @since 1.7.2
 */
public class SessionManager {

    int                   sessionIdCount = 1;
    private IntKeyHashMap sessionMap     = new IntKeyHashMap();
    private Session       sysSession;

// TODO:
//
// Eliminate the Database-centric nature of SessionManager.
// e.g. Sessions should be able to migrate from one Database instance
// to another using session control language moderated by
// SessionManager

    /**
     * Constructs an new SessionManager handling the specified Database.
     * Creates a SYS User.
     */
    public SessionManager(Database db) {

        User sysUser = db.getUserManager().getSysUser();

        sysSession = new Session(db, sysUser, false, false, 0);
    }

// TODO:
//
// It should be possible to create an initially 'disconnected' Session that
// can execute general commands using a SessionCommandInterpreter.
//
// EXAMPLES: Open a Session to start a Server, add/remove
//           databases hosted by an existing Server, connect to a
//           Database...
//
// REQUIRES:  auth scheme independent of any particular Database instance
//            e.g. provide service to use /etc/passwd and /etc/groups,
//                 JAAS-plugin, etc.

    /**
     *  Binds the specified Session object into this SessionManager's active
     *  Session registry. This method is typically called internally from
     * {@link
     *  Database#connect(String,String) Database.connect(username,password)}
     *  as the final step, when a successful connection has been made.
     *
     * @param db the database to which the new Session is initially connected
     * @param user the initial Session User
     * @param readonly the initial ReadOnly attribute for the new Session
     */
    public synchronized Session newSession(Database db, User user,
                                           boolean readonly, boolean forlog) {

        Session s = new Session(db, user, true, readonly, sessionIdCount);

        s.isProcessingLog = forlog;

        if (!forlog && sessionMap.isEmpty()) {
            HsqlException[] warnings = sysSession.getAndClearWarnings();

            for (int i = 0; i < warnings.length; i++) {
                s.addWarning(warnings[i]);
            }
        }

        sessionMap.put(sessionIdCount, s);

        sessionIdCount++;


        return s;
    }

    /**
     * Retrieves the special SYS Session.
     *
     * @return the special SYS Session
     */
    public Session getSysSession(String schema,
                                 boolean forScript) throws HsqlException {

        sysSession.currentSchema =
            sysSession.database.schemaManager.getSchemaHsqlName(schema);
        sysSession.isProcessingScript = forScript;
        sysSession.isProcessingLog    = false;

        sysSession.setUser(sysSession.database.getUserManager().getSysUser());

        return sysSession;
    }

    /**
     * Retrieves the special SYS Session.
     *
     * @return the special SYS Session
     */
    public Session getSysSession() {

        sysSession.currentSchema =
            sysSession.database.schemaManager.defaultSchemaHsqlName;
        sysSession.isProcessingScript = false;
        sysSession.isProcessingLog    = false;

        sysSession.setUser(sysSession.database.getUserManager().getSysUser());

        return sysSession;
    }

    /**
     * Retrieves the special SYS Session.
     *
     * @return the special SYS Session
     */
    public Session getSysSession(String schema,
                                 User user) throws HsqlException {

        sysSession.currentSchema =
            sysSession.database.schemaManager.getSchemaHsqlName(schema);
        sysSession.isProcessingScript = false;
        sysSession.isProcessingLog    = false;

        sysSession.setUser(user);

        return sysSession;
    }

/** @todo sig change should be either:  closeAllSessions(Database) or closeAllSessions(dbID) */

    /**
     * Closes all Sessions registered with this SessionManager.
     */
    public synchronized void closeAllSessions() {

        // don't disconnect system user; need it to save database
        Session[] sessions = getAllSessions();

        for (int i = 0; i < sessions.length; i++) {
            sessions[i].close();
        }
    }

    /**
     *  Removes the session from management and disconnects.
     *
     * @param  session to disconnect
     */
    synchronized void removeSession(Session session) {
        sessionMap.remove(session.getId());
    }

    /**
     * Removes all Sessions registered with this SessionManager.
     */
    synchronized void clearAll() {
        sessionMap.clear();
    }

    /**
     * Returns true if no session exists beyond the sys session.
     */
    synchronized boolean isEmpty() {
        return sessionMap.isEmpty();
    }

    /**
     * Retrieves a list of the Sessions in this container that
     * are visible to the specified Session, given the access rights of
     * the Session User.
     *
     * @param session The Session determining visibility
     * @return the Sessions visible to the specified Session
     */
    synchronized Session[] getVisibleSessions(Session session) {
        return session.isAdmin() ? getAllSessions()
                                 : new Session[]{ session };
    }

    /**
     * Retrieves the Session with the specified Session identifier or null
     * if no such Session is registered with this SessionManager.
     */
    synchronized Session getSession(int id) {
        return (Session) sessionMap.get(id);
    }

    public synchronized Session[] getAllSessions() {

        Session[] sessions = new Session[sessionMap.size()];
        Iterator  it       = sessionMap.values().iterator();

        for (int i = 0; it.hasNext(); i++) {
            sessions[i] = (Session) it.next();
        }

        return sessions;
    }

    public synchronized boolean isUserActive(String userName) {

        Iterator it = sessionMap.values().iterator();

        for (int i = 0; it.hasNext(); i++) {
            Session session = (Session) it.next();

            if (userName.equals(session.getUser().getName())) {
                return true;
            }
        }

        return false;
    }

    public synchronized void removeSchemaReference(Schema schema) {

        Iterator it = sessionMap.values().iterator();

        for (int i = 0; it.hasNext(); i++) {
            Session session = (Session) it.next();

            if (session.currentSchema == schema.name) {
                session.resetSchema();
            }
        }
    }
}