package org.apache.bookkeeper.client;
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*
*/
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.bookkeeper.client.QuorumEngine.Operation;
import org.apache.bookkeeper.client.QuorumEngine.Operation.AddOp;
import org.apache.bookkeeper.client.QuorumEngine.Operation.ReadOp;
import org.apache.log4j.Logger;
/**
* Thread responsible for delivering results to clients. This thread
* basically isolates the application from the remainder of the
* BookKeeper client.
*
*/
class ClientCBWorker extends Thread{
static Logger LOG = Logger.getLogger(ClientCBWorker.class);
static ClientCBWorker instance = null;
private volatile boolean stop;
private static int instanceCounter= 0;
ArrayBlockingQueue<Operation> pendingOps;
QuorumOpMonitor monitor;
static ClientCBWorker getInstance(){
if(instance == null){
instance = new ClientCBWorker();
}
instanceCounter++;
return instance;
}
/**
* Constructor initiates queue of pending operations and
* runs thread.
*
*/
ClientCBWorker(){
pendingOps = new ArrayBlockingQueue<Operation>(6000);
stop = false;
start();
LOG.info("Have started cbWorker");
}
/**
* Adds operation to queue of pending.
*
* @param op operation to add to queue
*/
void addOperation(Operation op)
throws InterruptedException {
pendingOps.put(op);
}
/**
* Gets thread out of its main loop.
*
*/
void shutdown(){
if((--instanceCounter) == 0){
stop = true;
instance = null;
LOG.info("Shutting down CBWorker");
}
}
/**
* Main thread loop.
*
*/
public void run(){
try{
while(!stop){
Operation op = pendingOps.poll(1000, TimeUnit.MILLISECONDS);
if(op != null){
synchronized(op){
while(!op.isReady()){
op.wait(1000);
}
}
switch(op.type){
case Operation.ADD:
AddOp aOp = (AddOp) op;
aOp.getLedger().setAddConfirmed(aOp.entry);
aOp.cb.addComplete(aOp.getErrorCode(),
aOp.getLedger(),
aOp.entry,
aOp.ctx);
break;
case Operation.READ:
ReadOp rOp = (ReadOp) op;
rOp.cb.readComplete(rOp.getErrorCode(),
rOp.getLedger(),
new LedgerSequence(rOp.seq),
rOp.ctx);
break;
}
}
}
} catch (InterruptedException e){
LOG.error("Exception while waiting on queue or operation");
}
}
}