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87 lines
2.0 KiB
87 lines
2.0 KiB
import java.util.List;
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import java.util.Vector;
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/**
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* A class which enables user to run a large chunk of
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* tasks in parallel efficiently.
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*
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* @author Jeffery 1-29-19
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*/
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public class TaskManager
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{
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/** Number of threads to use at once */
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private int threadCount;
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/** Meaningless tasks to run in parallel */
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private List<ReadTask> tasks;
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public TaskManager(int threadCount)
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{
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this.threadCount = threadCount;
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//using vectors because they are thread safe
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this.tasks = new Vector<>();
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}
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public void addTask(ReadTask t)
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{
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tasks.add(t);
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}
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/**
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* This is the fun method.
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*
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* This will run all of the tasks in parallel using the
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* desired amount of threads untill all of the jobs are
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* complete.
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*/
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public void runTasks()
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{
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int desiredThreads = threadCount > tasks.size() ?
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tasks.size() : threadCount;
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Thread[] runners = new Thread[desiredThreads];
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for(int i = 0; i < desiredThreads; i++)
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{
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runners[i] = new Thread(()->
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{
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ReadTask t = null;
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while(true)
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{
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//need synchronized block to prevent
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//race condition
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synchronized (tasks)
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{
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if(!tasks.isEmpty())
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t = tasks.remove(0);
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}
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if(t == null)
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{
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break;
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}
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else
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{
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t.runTask();
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t = null;
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}
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}
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});
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runners[i].start();
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}
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for(int i = 0; i < desiredThreads; i++)
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{
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try
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{
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runners[i].join();
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}
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catch (Exception e)
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{
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e.printStackTrace();
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}
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}
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}
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}
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