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/*
* Copyright 2001-2009 Terracotta, Inc.
*
* Licensed 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.quartz.impl.jdbcjobstore;
import java.sql.Connection;
/**
* An interface for providing thread/resource locking in order to protect
* resources from being altered by multiple threads at the same time.
*
* @author jhouse
*/
public interface Semaphore {
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Interface.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
/**
* Grants a lock on the identified resource to the calling thread (blocking
* until it is available).
*
* @param conn Database connection used to establish lock. Can be null if
* {@link #requiresConnection()} returns false.
*
* @return true if the lock was obtained.
*/
boolean obtainLock(Connection conn, String lockName) throws LockException;
/**
* Release the lock on the identified resource if it is held by the calling
* thread.
*/
void releaseLock(String lockName) throws LockException;
/**
* Whether this Semaphore implementation requires a database connection for
* its lock management operations.
*
* @see #obtainLock(Connection, String)
* @see #releaseLock(String)
*/
boolean requiresConnection();
}