rdbmentitylockstore.java

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/**
 * Copyright (c) 2002 The JA-SIG Collaborative.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the JA-SIG Collaborative
 *    (http://www.jasig.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE JA-SIG COLLABORATIVE "AS IS" AND ANY
 * EXPRESSED 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 THE JA-SIG COLLABORATIVE OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

package org.jasig.portal.concurrency.locking;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.jasig.portal.EntityTypes;
import org.jasig.portal.RDBMServices;
import org.jasig.portal.concurrency.IEntityLock;
import org.jasig.portal.concurrency.LockingException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * RDBMS-based store for <code>IEntityLocks</code>.
 * @author Dan Ellentuck
 * @version $Revision: 1.12.2.1 $
 */
public class RDBMEntityLockStore implements IEntityLockStore {
    private static final Log log = LogFactory.getLog(RDBMEntityLockStore.class);
    private static IEntityLockStore singleton;

    // Constants for the LOCK table:
    private static String LOCK_TABLE = "UP_ENTITY_LOCK";
    private static String ENTITY_TYPE_COLUMN = "ENTITY_TYPE_ID";
    private static String ENTITY_KEY_COLUMN = "ENTITY_KEY";
    private static String EXPIRATION_TIME_COLUMN = "EXPIRATION_TIME";
    private static String LOCK_OWNER_COLUMN = "LOCK_OWNER";
    private static String LOCK_TYPE_COLUMN = "LOCK_TYPE";
    private static String EQ = " = ";
    private static String GT = " > ";
    private static String LT = " < ";
    private static String QUOTE = "'";

    private static String allLockColumns;
    private static String addSql;
    private static String deleteLockSql;
    private static String updateSql;

    // Prior to jdk 1.4, java.sql.Timestamp.getTime() truncated milliseconds.
    private static boolean timestampHasMillis;
    static {
      Date testDate = new Date();
      Timestamp testTimestamp = new Timestamp(testDate.getTime());
      timestampHasMillis = (testDate.getTime() == testTimestamp.getTime());
    }
/**
 * RDBMEntityGroupStore constructor.
 */
public RDBMEntityLockStore() throws LockingException
{
    super();
    initialize();
}

/**
 * Adds the lock to the underlying store.
 * @param lock
 */
public void add(IEntityLock lock) throws LockingException
{
    Connection conn = null;
    try
    {
        conn = RDBMServices.getConnection();
        primDeleteExpired(new Date(), lock.getEntityType(), lock.getEntityKey(), conn);
        primAdd(lock, conn);
    }

    catch (SQLException sqle)
        { throw new LockingException("Problem creating " + lock + ": " + sqle.getMessage()); }

    finally
        { RDBMServices.releaseConnection(conn); }
}

/**
 * If this IEntityLock exists, delete it.
 * @param lock
 */
public void delete(IEntityLock lock) throws LockingException
{
    Connection conn = null;
    try
    {
        conn = RDBMServices.getConnection();
        primDelete(lock, conn);
    }

    catch (SQLException sqle)
        { throw new LockingException("Problem deleting " + lock + " : " + sqle.getMessage()); }
    finally
        { RDBMServices.releaseConnection(conn); }
}

/**
 * Delete all IEntityLocks from the underlying store.
 */
public void deleteAll() throws LockingException
{
    Connection conn = null;
    Statement stmnt = null;
    ResultSet rs = null;
    try
    {
        String sql = "DELETE FROM " + LOCK_TABLE;
        log.debug("RDBMEntityLockStore.deleteAll(): " + sql);

        conn = RDBMServices.getConnection();
        try
        {
            stmnt = conn.createStatement();
            int rc = stmnt.executeUpdate(sql);
            String msg = "Deleted " + rc + " locks.";
            log.debug("RDBMEntityLockStore.deleteAll(): " + msg);
        }
        finally
            { if ( stmnt != null ) stmnt.close(); }
    }
    catch (SQLException sqle)
        { throw new LockingException("Problem deleting locks: " + sqle.getMessage()); }

    finally
        { RDBMServices.releaseConnection(conn); }
}

/**
 * Delete all expired IEntityLocks from the underlying store.
 * @param expiration 
 */
public void deleteExpired(Date expiration) throws LockingException
{
    deleteExpired(expiration, null, null);
}

/**
 * Delete IEntityLocks from the underlying store that have expired as of
 * <code>expiration</code>.  Params <code>entityType</code> and
 * <code>entityKey</code> are optional.
 *
 * @param expiration java.util.Date
 * @param entityType Class
 * @param entityKey String
 */
public void deleteExpired(Date expiration, Class entityType, String entityKey)
throws LockingException
{
    Connection conn = null;
    try
    {
        conn = RDBMServices.getConnection();
        primDeleteExpired(expiration, entityType, entityKey, conn);
    }

    catch (SQLException sqle)
        { throw new LockingException("Problem deleting expired locks: " + sqle.getMessage()); }
    finally
        { RDBMServices.releaseConnection(conn); }
}

/**
 * Delete all expired IEntityLocks from the underlying store.
 * @param lock IEntityLock
 */
public void deleteExpired(IEntityLock lock) throws LockingException
{
    deleteExpired(new Date(), lock.getEntityType(), lock.getEntityKey());
}

 /**
 * Retrieve IEntityLocks from the underlying store.  Any or all of the parameters
 * may be null.
 * @param entityType Class
 * @param entityKey String
 * @param lockType Integer - so we can accept a null value.
 * @param expiration Date
 * @param lockOwner String
 * @exception LockingException - wraps an Exception specific to the store.
 */
public IEntityLock[] find
    (Class entityType,
    String entityKey,
    Integer lockType,
    Date expiration,
    String lockOwner )
throws LockingException
{
    return select(entityType, entityKey, lockType, expiration, lockOwner);
}

 /**
 * Retrieve IEntityLocks from the underlying store.  Expiration must not be null.
 * @param expiration Date
 * @param entityType Class
 * @param entityKey String
 * @param lockType Integer - so we can accept a null value.
 * @param lockOwner String
 * @exception LockingException - wraps an Exception specific to the store.
 */
public IEntityLock[] findUnexpired (
    Date expiration,
    Class entityType,
    String entityKey,
    Integer lockType,
    String lockOwner)
throws LockingException
{
    Timestamp ts = new Timestamp(expiration.getTime());
    return selectUnexpired(ts, entityType, entityKey, lockType, lockOwner);
}

/**
 * SQL for inserting a row into the lock table.
 */
private static String getAddSql()
{
    if ( addSql == null )
    {
        addSql = "INSERT INTO " + LOCK_TABLE +
          "(" + getAllLockColumns() + ") VALUES (?, ?, ?, ?, ?)";
    }
    return addSql;
}

/**
 * @return java.lang.String
 */
private static java.lang.String getAllLockColumns()
{
    if ( allLockColumns == null )
    {
        StringBuffer buff = new StringBuffer(100);
        buff.append(ENTITY_TYPE_COLUMN);
        buff.append(", ");
        buff.append(ENTITY_KEY_COLUMN);
        buff.append(", ");
        buff.append(LOCK_TYPE_COLUMN);
        buff.append(", ");
        buff.append(EXPIRATION_TIME_COLUMN);
        buff.append(", ");
        buff.append(LOCK_OWNER_COLUMN);

        allLockColumns = buff.toString();
    }
    return allLockColumns;
}

/**
 * SQL for deleting a row on the lock table.
 */
private static String getDeleteLockSql()
{
    if ( deleteLockSql == null )
    {
        deleteLockSql = "DELETE FROM " + LOCK_TABLE +
          " WHERE " + ENTITY_TYPE_COLUMN + EQ + "?" +
            " AND " + ENTITY_KEY_COLUMN  + EQ + "?" +
            " AND " + EXPIRATION_TIME_COLUMN + EQ + "?" +
            " AND " + LOCK_TYPE_COLUMN + EQ + "?" +
            " AND " + LOCK_OWNER_COLUMN + EQ + "?";
    }
    return deleteLockSql;
}

/**
 * @return java.lang.String
 */
private static java.lang.String getSelectSql()
{
    return ( "SELECT " + getAllLockColumns() + " FROM " + LOCK_TABLE);
}

/**
 * SQL for updating a row on the lock table.
 */
private static String getUpdateSql()
{
    if ( updateSql == null )
    {
        updateSql = "UPDATE " + LOCK_TABLE +
        " SET " + EXPIRATION_TIME_COLUMN + EQ + "?, " + LOCK_TYPE_COLUMN + EQ + "?"+
          " WHERE " + ENTITY_TYPE_COLUMN + EQ + "?" +
            " AND " + ENTITY_KEY_COLUMN + EQ  + "?" +
            " AND " + LOCK_OWNER_COLUMN + EQ  + "?" +
            " AND " + EXPIRATION_TIME_COLUMN + EQ + "?" +
            " AND " + LOCK_TYPE_COLUMN + EQ + "?";
    }
    return updateSql;
}

/**
 * Cleanup the store by deleting locks expired an hour ago.
 */
private void initialize()throws LockingException
{
    Date expiration = new Date(System.currentTimeMillis() - (60*60*1000));
    deleteExpired(expiration, null, null);
}

/**
 * Extract values from ResultSet and create a new lock.
 * @return org.jasig.portal.groups.IEntityLock
 * @param rs java.sql.ResultSet
 */
private IEntityLock instanceFromResultSet(java.sql.ResultSet rs)
throws  SQLException, LockingException
{
    IEntityLock lock = null;

    Integer entityTypeID = new Integer(rs.getInt(1));
    Class entityType = EntityTypes.getEntityType(entityTypeID);
    String key = rs.getString(2);
    int lockType = rs.getInt(3);
    Timestamp ts = rs.getTimestamp(4);
    String lockOwner = rs.getString(5);

    return newInstance(entityType, key, lockType, ts, lockOwner);
}

/**
 * @return org.jasig.portal.concurrency.locking.IEntityLock
 */
private IEntityLock newInstance (
    Class entityType,
    String entityKey,
    int lockType,
    Date expirationTime,
    String lockOwner ) throws LockingException
{
    return new EntityLockImpl(entityType, entityKey, lockType, expirationTime, lockOwner);
}

/**
 * Add the lock to the underlying store.
 * @param lock org.jasig.portal.concurrency.locking.IEntityLock
 * @param conn java.sql.Connection
 */
private void primAdd(IEntityLock lock, Connection conn)
throws SQLException, LockingException
{
    Integer typeID = EntityTypes.getEntityTypeID(lock.getEntityType());
    String key = lock.getEntityKey();
    int lockType = lock.getLockType();