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Object Automation library
/* Copyright 1999 Vince Via [email protected]
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 com.viaoa.ds.jdbc.connection;
import java.util.*;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.sql.*;
/**
Used to wrap functionality around a java.sql.Connection to offer
Statement and PreparedStatement Pooling. Mostly used internally by ConnectionPool.
*/
public class OAConnection {
private static Logger LOG = Logger.getLogger(OAConnection.class.getName());
protected Connection connection;
protected Vector vecStatement = new Vector(5,5);
protected Vector vecUsedPreparedStatement = new Vector(5,5);
protected volatile boolean bAvailable;
protected volatile boolean bGettingStatement;
private ConcurrentHashMap> hmSqlToPreparedStatements = new ConcurrentHashMap>();
private ConcurrentHashMap hmPreparedStatementToSql = new ConcurrentHashMap();
volatile int cntGetStatement;
volatile int cntCreateStatement;
volatile int cntReleaseStatement;
volatile int cntGetPreparedStatement;
volatile int cntCreatePreparedStatement;
volatile int cntReleasePreparedStatement;
public OAConnection(Connection con) {
connection = con;
}
public Statement getStatement(String message) throws SQLException {
Statement statement = null;
cntGetStatement++;
synchronized (vecStatement) {
int x = vecStatement.size();
for (int i=0 ; i < x; i++) {
Pool pool = (Pool) vecStatement.elementAt(i);
if (pool.used) continue;
if (pool.statement.isClosed()) {
vecStatement.remove(i);
i--;
x--;
continue;
}
pool.used = true;
bGettingStatement = false;
return pool.statement;
}
}
// 20120625 can use later, need to test
// statement = connection.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, ResultSet.HOLD_CURSORS_OVER_COMMIT);
statement = connection.createStatement();
cntCreateStatement++;
// statement.setPoolable(true); // 20120625 can use later, need to test
Pool pool = new Pool(statement,true, message);
synchronized (vecStatement) {
vecStatement.addElement(pool);
bGettingStatement = false;
}
if (vecStatement.size() > 20) {
LOG.warning("StatementPool is getting large, current="+vecStatement.size());
}
return statement;
}
/** returns true if found */
public boolean releaseStatement(Statement statement) {
boolean bResult = false;
synchronized (vecStatement) {
int x = vecStatement.size();
for (int i=0 ; i < x; i++) {
Pool pool = (Pool) vecStatement.elementAt(i);
if (pool.statement != statement) continue;
pool.used = false;
bResult = true;
if (vecStatement.size() < 10) break;
try {
if (!statement.isClosed()) {
statement.close();
}
}
catch (Exception e) {
LOG.log(Level.WARNING, "Exception releasing statement", e);
}
vecStatement.remove(i);
break;
}
}
if (bResult) cntReleaseStatement++;
return bResult;
}
public PreparedStatement getPreparedStatement(String sql, boolean bHasAutoGenerated) throws SQLException {
ArrayList al = null;
synchronized (vecUsedPreparedStatement) {
cntGetPreparedStatement++;
al = hmSqlToPreparedStatements.get(sql);
if (al == null) {
al = new ArrayList();
hmSqlToPreparedStatements.put(sql, al);
}
else {
for (PreparedStatement ps : al) {
if (!vecUsedPreparedStatement.contains(ps)) {
vecUsedPreparedStatement.addElement(ps);
bGettingStatement = false;
return ps;
}
}
}
}
PreparedStatement ps;
if (bHasAutoGenerated) ps = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
else ps = connection.prepareStatement(sql);
cntCreatePreparedStatement++;
synchronized (vecUsedPreparedStatement) {
vecUsedPreparedStatement.addElement(ps);
bGettingStatement = false;
al.add(ps);
hmPreparedStatementToSql.put(ps, sql);
}
return ps;
}
public boolean releasePreparedStatement(PreparedStatement ps, boolean bCanBeReused) {
boolean bFound = false;
synchronized (vecUsedPreparedStatement) {
int x = vecUsedPreparedStatement.size();
for (int i=0; i < x; i++) {
PreparedStatement ps2 = vecUsedPreparedStatement.elementAt(i);
if (ps2 != ps) continue;
vecUsedPreparedStatement.removeElementAt(i);
bFound = true;
break;
}
}
synchronized (vecUsedPreparedStatement) {
String sql = hmPreparedStatementToSql.get(ps);
if (sql != null) {
ArrayList al = hmSqlToPreparedStatements.get(sql);
if (al != null && ((bFound && !bCanBeReused) || al.size() > 5)) {
try {
if (!ps.isClosed()) ps.close();
}
catch (Exception e) {
}
al.remove(ps);
if (al.size() == 0) hmSqlToPreparedStatements.remove(sql);
hmPreparedStatementToSql.remove(ps);
}
}
}
return bFound;
}
public int getTotalUsed() {
int x = vecUsedPreparedStatement.size();
x += getCurrentlyUsedStatementCount();
if (bGettingStatement) x++;
return x;
}
protected int getCurrentlyUsedStatementCount() {
int totalUsed = 0;;
synchronized (vecStatement) {
int x = vecStatement.size();
for (int i=0 ; i < x; i++) {
Pool pool = (Pool) vecStatement.elementAt(i);
if (pool.used) totalUsed++;
}
}
return totalUsed;
}
public void getInfo(Vector vec) {
try {
if (connection.isClosed()) vec.addElement(" Connection is closed");
}
catch (Exception e) {
}
synchronized (vecStatement) {
int x = vecStatement.size();
for (int i=0 ; i < x; i++) {
Pool pool = (Pool) vecStatement.elementAt(i);
if (pool.used) {
// vec.addElement(" "+i+") "+pool.message);
}
}
}
/*
vec.add(" GetStatement count="+cntGetStatement);
vec.add(" CreateStatement count="+cntCreateStatement);
vec.add(" ReleaseStatement count="+cntReleaseStatement);
vec.add(" GetPreparedStatement count="+cntGetPreparedStatement);
vec.add(" CreatePreparedStatement count="+cntCreatePreparedStatement);
vec.add(" ReleasePreparedStatement count="+cntReleasePreparedStatement);
*/
}
/** internal class used by Connection to get a list of Statement objects
*/
class Pool {
Statement statement;
boolean used;
String message;
public Pool(Statement s, boolean b, String message) {
statement = s;
used = b;
this.message = message;
}
}
public int getTotalPreparedStatements() {
int i = 0;
for (Entry> entry : hmSqlToPreparedStatements.entrySet()) {
i += entry.getValue().size();
}
return i;
}
}
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