java - Single process blocking queue -

i writing application communicates hardware. while application can receive , process multiple requests simultaneously in parallel, hardware cannot!

the hardware requires these parallel requests organised linear request chain each 1 executed 1 after other.

i have requirement able prioritise requests given of background processes no urgency , live , need jumped front of queue immediate processing.

i don't have experience queues surprised if such library didn't exist.

see https://docs.oracle.com/javase/7/docs/api/java/util/priorityqueue.html

i advise using wrapper requests has priority value queue. instance, can use long value, calculate

value = timestamp % n * prioritylevel  

n dependent on how long takes process events

prioritylevel value lower means more urgent (bigger zero)

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edit: after specification in comments

it seems need create instance of threadpoolexecutor , pass own queue instance of priorityblockingqueue. task put pool need implement comparable order them execution priority.

see bit old reference, inspiration should sufficient.

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edit: suggested priority function dangerous smaller n, looking @ numbers, long can multiplied lot before overflow happen, leaving modulo out little , less, if have 2 priority levels (sorry mystification)

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edit: implementation of suggested solution

import java.util.concurrent.priorityblockingqueue; import java.util.concurrent.threadpoolexecutor; import java.util.concurrent.timeunit;  public class qtest {     public static void main(string[] args){         //create executor 1 thread (first 4 arguments)         //using priority queue store tasks (it takes care of sorting priority)         threadpoolexecutor executor = new threadpoolexecutor(1, 1, 0, timeunit.milliseconds, new priorityblockingqueue());         executor.execute(new eventwrapper(1, "a"));         executor.execute(new eventwrapper(2, "b"));         executor.execute(new eventwrapper(1, "c"));         executor.execute(new eventwrapper(3, "d"));         executor.execute(new eventwrapper(1, "e"));         //just have terminated once test done         executor.shutdown();     } }  //in wrapper should loaded want have executed class eventwrapper implements comparable<eventwrapper>, runnable{     public final long priority;     //name recognize being executed     public final string name;     public eventwrapper(int priority, string name){         //priority function out of current time, can inserted elsewhere         this.priority = priority*system.currenttimemillis();         this.name = name;     }      @override     public int compareto(eventwrapper that) {         //lower priority first         if(this.priority==that.priority)return 0;         return this.priority>that.priority?1:-1;     }      @override     public void run() {         system.out.println("executing task "+name+" priority "+priority);         //sleep rule out speed of insertion in executor         try {thread.sleep(1000);         } catch (interruptedexception ex) {}     } } 

result created tasks is

executing task priority 1433276819484 executing task c priority 1433276819485 executing task e priority 1433276819485 executing task b priority 2866553638970 executing task d priority 4299830458455