com.sun.jts.CosTransactions.CoordinatorLogPool Maven / Gradle / Ivy
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package com.sun.jts.CosTransactions;
// Import required classes.
import java.util.*;
/**
* The CoordinatorLogPool is used as a cache for CoordinatorLog objects.
* This pool allows the re-use of these objects which are very expensive
* to instantiate.
*
* The pool is used by replacing calls to 'new CoordinatorLog()' in the
* TopCoordinator with calls to CoordinatorLogPool.getCoordinatorLog().
* The getCoordinatorLog() method attempts to return a CoordinatorLog
* from the pool. If the pool is empty it instantiates a new
* CoordinatorLog.
*
* Objects are re-used by calling CoordinatorLogPool.putCoordinatorLog()
* to return a CoordinatorLog object back to the pool. At this time a
* check is made to ensure that the internal pool size doesn't exceed a
* pre set limit. If it does, then the object is discarded and not put
* back into the pool.
*
* The pool was added to improve performance of transaction logging
*
* @version 1.00
*
* @author Arun Krishnan
*
* @see
*/
class CoordinatorLogPool {
private Stack pool;
private static final int MAXSTACKSIZE = 3;
public static CoordinatorLogPool CLPool = new CoordinatorLogPool();
public static Hashtable CLPooltable = new Hashtable();
/**
* constructor
*
*/
public CoordinatorLogPool() {
pool = new Stack();
}
/**
* get a CoordinatorLog object from the cache. Instantiate a
* new CoordinatorLog object if the cache is empty.
*
*/
public static synchronized CoordinatorLog getCoordinatorLog() {
if (Configuration.isDBLoggingEnabled() ||
Configuration.isFileLoggingDisabled())
return null;
if (CLPool.pool.empty()) {
return new CoordinatorLog();
}
else {
CoordinatorLog cl = (CoordinatorLog) CLPool.pool.pop();
return cl;
}
}
/**
* return a CoordinatorLog object to the cache. To limit the size of
* the cache a check is made to ensure that the cache doesn't
* already have more that MAXSTACKSIZE elements. If so the object
* being returned is discarded.
*
*/
public static void putCoordinatorLog(CoordinatorLog cl) {
if (CLPool.pool.size() <= MAXSTACKSIZE) {
CLPool.pool.push(cl);
}
}
// Added to support delegated recovery: multiple logs should coexist
public static synchronized CoordinatorLog getCoordinatorLog(String logPath) {
CoordinatorLogPool clpool = (CoordinatorLogPool)CLPooltable.get(logPath);
if (clpool == null) {
clpool = new CoordinatorLogPool();
CLPooltable.put(logPath,clpool);
}
if (clpool.pool.empty()) {
return new CoordinatorLog(logPath);
}
else {
return (CoordinatorLog)clpool.pool.pop();
}
}
// Added to support delegated recovery: multiple logs should coexist
public static void putCoordinatorLog(CoordinatorLog cl, String logPath) {
CoordinatorLogPool clpool = (CoordinatorLogPool)CLPooltable.get(logPath);
if (clpool == null) {
clpool = new CoordinatorLogPool();
CLPooltable.put(logPath,clpool);
}
if (clpool.pool.size() <= MAXSTACKSIZE) {
clpool.pool.push(cl);
}
}
}