/*
Copyright (c) 2010 by Peter Stamfest <peter@stamfest.at>
This file is part of java-rrd.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
Except as contained in this notice, the name of Peter Stamfest shall not
be used in advertising or otherwise to promote the sale, use or other
dealings in this Software without prior written authorization from
Peter Stamfest.
*/
package javarrd.net.stamfest.rrd;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
class RRDPoolMember {
int requestcount = 0;
boolean inuse = false;
RRDCommand rrdp;
}
class RRDPoolMemberWrapper implements RRDCommand {
RRDPoolMember member;
public RRDPoolMemberWrapper(RRDPoolMember member) {
this.member = member;
}
@Override
public void finish() {
member.rrdp.finish();
member.rrdp = null;
}
@Override
public CommandResult command(String[] cmd) throws Exception {
return member.rrdp.command(cmd);
}
};
public class RRDCommandPool implements RRDCommand {
private int poolsize = 4;
private int maxRequestsPerMember = 100;
private boolean finished = false;
private RRDCommandFactory factory = null;
RRDPoolMember pool[] = null;
public RRDCommandPool(String basedir, String cachedAddress) {
init(4, basedir, cachedAddress);
}
public RRDCommandPool(int poolsize, String basedir, String cachedAddress) {
init(poolsize, basedir, cachedAddress);
}
public RRDCommandPool(int poolsize, RRDCommandFactory factory) {
init(poolsize, factory);
}
private void init(int poolsize,
final String basedir,
final String cachedAddress) {
init(poolsize, new RRDCommandFactory() {
@Override
public RRDp createRRDCommand() {
RRDp rrdp = null;
try {
rrdp = new RRDp(basedir, cachedAddress);
} catch (IOException ex) {
Logger.getLogger(RRDCommandPool.class.getName()).log(Level.SEVERE, null, ex);
}
return rrdp;
}
});
}
/**
* @param poolsize
*/
private void init(int poolsize, RRDCommandFactory factory) {
this.poolsize = poolsize;
this.factory = factory;
pool = new RRDPoolMember[poolsize];
}
public RRDCommand getConnection() throws Exception {
if (finished) throw new Exception("Already finished");
RRDPoolMember member = null;
synchronized (this) {
while (true) {
for (int i = 0; i < poolsize; i++) {
if (pool[i] == null) {
pool[i] = new RRDPoolMember();
member = pool[i];
break;
} else if (!pool[i].inuse) {
member = pool[i];
break;
}
}
if (member != null) {
member.inuse = true;
break;
} else {
try {
wait();
} catch (InterruptedException e) {
// ignore
}
// next loop iteration
}
}
}
member.requestcount++;
if (member.rrdp == null) {
member.requestcount = 0;
member.rrdp = factory.createRRDCommand();
}
return new RRDPoolMemberWrapper(member);
}
public void done(RRDCommand cmd) {
if (cmd instanceof RRDPoolMemberWrapper) {
RRDPoolMember member = ((RRDPoolMemberWrapper) cmd).member;
if (member.requestcount > maxRequestsPerMember) {
if (member.rrdp != null) {
// this may happen in case of a previous error
member.rrdp.finish();
}
member.requestcount = 0;
member.rrdp = null;
}
synchronized (this) {
member.inuse = false;
notify();
}
}
}
private void kick(RRDCommand cmd) {
if (cmd instanceof RRDPoolMemberWrapper) {
RRDPoolMember member = ((RRDPoolMemberWrapper) cmd).member;
if (member.rrdp != null) {
// this may happen in case of a previous error
member.rrdp.finish();
}
member.requestcount = 0;
member.rrdp = null;
synchronized (this) {
member.inuse = false;
notify();
}
}
}
@Override
public CommandResult command(String[] cmd) throws Exception {
RRDCommand rrdcmd = getConnection();
try {
return rrdcmd.command(cmd);
} catch (Exception e) {
kick(rrdcmd);
throw e;
} finally {
done(rrdcmd);
}
}
public int getMaxRequestsPerMember() {
return maxRequestsPerMember;
}
public void setMaxRequestsPerMember(int maxRequestsPerMember) {
this.maxRequestsPerMember = maxRequestsPerMember;
}
public int getPoolsize() {
return poolsize;
}
@Override
public void finish() {
finished = true;
synchronized (this) {
boolean alldone = false;
while (!alldone) {
alldone = true;
for (int i = 0; i < poolsize; i++) {
if (pool[i] == null) continue;
if (!pool[i].inuse) {
if (pool[i].rrdp != null) {
pool[i].rrdp.finish();
pool[i].rrdp = null;
pool[i] = null;
}
continue;
} else {
alldone = false;
// in use - have to wait
try {
wait();
} catch (InterruptedException e) {
// ignore
}
break;
}
}
}
}
}
public RRDCommandFactory getFactory() {
return factory;
}
public void setFactory(RRDCommandFactory factory) {
this.factory = factory;
}
}