org.quartz.impl.jdbcjobstore.DBSemaphore Maven / Gradle / Ivy
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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;
import java.util.HashSet;
import io.logspace.jvm.agent.shaded.slf4j.Logger;
import io.logspace.jvm.agent.shaded.slf4j.LoggerFactory;
/**
* Base class for database based lock handlers for providing thread/resource locking
* in order to protect resources from being altered by multiple threads at the
* same time.
*/
public abstract class DBSemaphore implements Semaphore, Constants,
StdJDBCConstants, TablePrefixAware {
private final Logger log = LoggerFactory.getLogger(getClass());
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Data members.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
ThreadLocal> lockOwners = new ThreadLocal>();
private String sql;
private String insertSql;
private String tablePrefix;
private String schedName;
private String expandedSQL;
private String expandedInsertSQL;
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Constructors.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
public DBSemaphore(String tablePrefix, String schedName, String defaultSQL, String defaultInsertSQL) {
this.tablePrefix = tablePrefix;
this.schedName = schedName;
setSQL(defaultSQL);
setInsertSQL(defaultInsertSQL);
}
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Interface.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
protected Logger getLog() {
return log;
}
private HashSet getThreadLocks() {
HashSet threadLocks = lockOwners.get();
if (threadLocks == null) {
threadLocks = new HashSet();
lockOwners.set(threadLocks);
}
return threadLocks;
}
/**
* Execute the SQL that will lock the proper database row.
*/
protected abstract void executeSQL(Connection conn, String lockName, String theExpandedSQL, String theExpandedInsertSQL)
throws LockException;
/**
* Grants a lock on the identified resource to the calling thread (blocking
* until it is available).
*
* @return true if the lock was obtained.
*/
public boolean obtainLock(Connection conn, String lockName)
throws LockException {
if(log.isDebugEnabled()) {
log.debug(
"Lock '" + lockName + "' is desired by: "
+ Thread.currentThread().getName());
}
if (!isLockOwner(lockName)) {
executeSQL(conn, lockName, expandedSQL, expandedInsertSQL);
if(log.isDebugEnabled()) {
log.debug(
"Lock '" + lockName + "' given to: "
+ Thread.currentThread().getName());
}
getThreadLocks().add(lockName);
//getThreadLocksObtainer().put(lockName, new
// Exception("Obtainer..."));
} else if(log.isDebugEnabled()) {
log.debug(
"Lock '" + lockName + "' Is already owned by: "
+ Thread.currentThread().getName());
}
return true;
}
/**
* Release the lock on the identified resource if it is held by the calling
* thread.
*/
public void releaseLock(String lockName) {
if (isLockOwner(lockName)) {
if(getLog().isDebugEnabled()) {
getLog().debug(
"Lock '" + lockName + "' returned by: "
+ Thread.currentThread().getName());
}
getThreadLocks().remove(lockName);
//getThreadLocksObtainer().remove(lockName);
} else if (getLog().isDebugEnabled()) {
getLog().warn(
"Lock '" + lockName + "' attempt to return by: "
+ Thread.currentThread().getName()
+ " -- but not owner!",
new Exception("stack-trace of wrongful returner"));
}
}
/**
* Determine whether the calling thread owns a lock on the identified
* resource.
*/
public boolean isLockOwner(String lockName) {
return getThreadLocks().contains(lockName);
}
/**
* This Semaphore implementation does use the database.
*/
public boolean requiresConnection() {
return true;
}
protected String getSQL() {
return sql;
}
protected void setSQL(String sql) {
if ((sql != null) && (sql.trim().length() != 0)) {
this.sql = sql.trim();
}
setExpandedSQL();
}
protected void setInsertSQL(String insertSql) {
if ((insertSql != null) && (insertSql.trim().length() != 0)) {
this.insertSql = insertSql.trim();
}
setExpandedSQL();
}
private void setExpandedSQL() {
if (getTablePrefix() != null && getSchedName() != null && sql != null && insertSql != null) {
expandedSQL = Util.rtp(this.sql, getTablePrefix(), getSchedulerNameLiteral());
expandedInsertSQL = Util.rtp(this.insertSql, getTablePrefix(), getSchedulerNameLiteral());
}
}
private String schedNameLiteral = null;
protected String getSchedulerNameLiteral() {
if(schedNameLiteral == null)
schedNameLiteral = "'" + schedName + "'";
return schedNameLiteral;
}
public String getSchedName() {
return schedName;
}
public void setSchedName(String schedName) {
this.schedName = schedName;
setExpandedSQL();
}
protected String getTablePrefix() {
return tablePrefix;
}
public void setTablePrefix(String tablePrefix) {
this.tablePrefix = tablePrefix;
setExpandedSQL();
}
}