java自定义LinkedBlockingQueue死锁
我一直在ThreadExecutorPool
内使用自定义blockingqueue,但有时任务工作者不接受任务,dispacher线程也不将新任务放入队列
我想知道以下自定义阻塞队列实现会导致死锁。这个代码有什么错误吗?
对于add()
和take()
方法,Is最好使用和synchronized
块
import java.util.Collection;
import java.util.concurrent.LinkedBlockingQueue;
import org.apache.log4j.Logger;
import com.ttech.utils.alarm.Alarm;
import com.ttech.utils.alarm.AlarmInterface;
import com.ttech.utils.counter.Counter;
import com.ttech.utils.counter.SNMPAgent;
public class WorkerQueue<E> extends LinkedBlockingQueue<E> {
private static final long serialVersionUID = 1L;
public Integer lowThreshold;
public Integer highThreshold;
public Integer capacity;
public String name;
public String type;
public Counter counter = null;
public boolean writeAlarmLog;
public static final Logger logger = Logger.getLogger(WorkerQueue.class);
public static Alarm HighThresholdAlarm = null;
public static Alarm CapacityAlarm = null;
// Check the size here and clear capacity and high threshold alarms in case
public E take() throws InterruptedException {
E data = super.take();
counter.setNewValue(super.size());
if (super.size() == lowThreshold) {
if(!this.writeAlarmLog) {
HighThresholdAlarm.clear(name);
CapacityAlarm.clear(name);
} else {
HighThresholdAlarm.clearLog(name, "Queue High Threshold");
CapacityAlarm.clearLog(name, "Queue Capacity Overload");
}
}
return data;
}
public E poll() {
E data = super.poll();
counter.setNewValue(super.size());
if (super.size() == lowThreshold) {
if(!this.writeAlarmLog) {
HighThresholdAlarm.clear(name);
CapacityAlarm.clear(name);
} else {
HighThresholdAlarm.clearLog(name, "Queue High Threshold");
CapacityAlarm.clearLog(name, "Queue Capacity Overload");
}
}
return data;
}
public int drainTo(Collection<? super E> c, int maxElements){
int size = super.drainTo(c,maxElements);
counter.setNewValue(super.size());
return size;
}
// During adding the data to queue check capacity and high threshold raise alarm in case
public boolean add(E data) {
Boolean rc = true;
if (capacity > 0) {
if (this.size() >= capacity) {
logger.error("Queue " + name + " is over capacity");
if(!this.writeAlarmLog)
CapacityAlarm.raise(name);
else
CapacityAlarm.raiseLog(AlarmInterface.AS_CRITICAL, name, "Queue Capacity Overload");
return false;
}
}
if (!super.add(data)) {
logger.error("Cannot add data to queue:" + name);
rc = false;
} else {
counter.setNewValue(super.size());
}
if (highThreshold == super.size()) {
if(!this.writeAlarmLog)
HighThresholdAlarm.raise(name);
else
HighThresholdAlarm.raiseLog(AlarmInterface.AS_CRITICAL, name, "Queue High Threshold");
}
return rc;
}
}
# 1 楼答案
ThreadPoolExecutor
不将add
任务分配到其工作队列。它offers它们,如果不接受,则将它们传递给配置的RejectedExecutionHandler。默认情况下,这是abort policy handler,导致抛出RejectedExecutionException
将永远不会调用自定义队列中的
add
方法如果要跟踪正在执行的任务数量的变化,我建议重写执行器本身的
beforeExecute
或afterExecute
方法。活动任务的数量可以从getActiveCount
获得