Threading improvements
This commit is contained in:
Graham Triggs
parent
f43db39084
commit
4d8bfe1a65
1 changed files with 60 additions and 34 deletions
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@ -5,7 +5,6 @@ package edu.cornell.mannlib.vitro.webapp.visualization.utilities;
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import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
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import edu.cornell.mannlib.vitro.webapp.utils.threads.VitroBackgroundThread;
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import java.util.ArrayList;
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import java.util.Date;
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import java.util.HashMap;
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import java.util.HashSet;
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@ -18,7 +17,7 @@ import java.util.concurrent.TimeUnit;
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import java.util.concurrent.TimeoutException;
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/**
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* Utilicy class that populates and returns a cache.
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* Utility class that populates and returns a cache.
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* Once the cache is populated, it can return the cached results whilst refreshing in the background.
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*
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* @param <T>
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@ -30,7 +29,7 @@ public class CachingRDFServiceExecutor<T> {
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private T cachedResults;
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private long lastCacheTime;
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private RDFServiceCallable<T> resultBuilder;
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private final RDFServiceCallable<T> resultBuilder;
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/**
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* Background task tracker
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@ -82,7 +81,7 @@ public class CachingRDFServiceExecutor<T> {
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}
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}
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} else {
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// No cached results, so fetch the results using any availabe RDF service
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// No cached results, so fetch the results using any available RDF service
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if (rdfService != null) {
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startBackgroundTask(rdfService);
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} else if (backgroundRDFService != null) {
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@ -125,8 +124,8 @@ public class CachingRDFServiceExecutor<T> {
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startBackgroundTask(backgroundRDFService);
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completeBackgroundTaskAsync();
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} else if (rdfService != null) {
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// No background service, so use the paassed RDF service, and wait for completion
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startBackgroundTask(backgroundRDFService);
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// No background service, so use the passed RDF service, and wait for completion
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startBackgroundTask(rdfService);
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completeBackgroundTask();
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}
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}
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@ -210,11 +209,7 @@ public class CachingRDFServiceExecutor<T> {
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backgroundCompletion = new Thread(new Runnable() {
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@Override
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public void run() {
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try {
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Thread.sleep(500);
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completeBackgroundTask(-1);
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} catch (InterruptedException e) {
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}
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completeBackgroundTask(-1);
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}
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});
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backgroundCompletion.setDaemon(true);
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@ -258,11 +253,8 @@ public class CachingRDFServiceExecutor<T> {
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abortBackgroundTask();
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} catch (ExecutionException e) {
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// There was a problem inside the task, so abort and throw an exception
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try {
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abortBackgroundTask();
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} finally {
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throw new RuntimeException("Background RDF thread through an exception", e.getCause());
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}
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abortBackgroundTask();
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throw new RuntimeException("Background RDF thread through an exception", e.getCause());
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} catch (TimeoutException e) {
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// Ignore a timeout waiting for the results
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}
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@ -312,7 +304,7 @@ public class CachingRDFServiceExecutor<T> {
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/**
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* Entry point for the background threads, ensuring the right start / cleanup is done
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* @throws Exception
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* @throws Exception Any exception
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*/
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@Override
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final public T call() throws Exception {
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@ -348,7 +340,7 @@ public class CachingRDFServiceExecutor<T> {
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/**
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* Method for users to implement, to return the results
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* @param rdfService An RDFService
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* @throws Exception
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* @throws Exception Any exception
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*/
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protected abstract T callWithService(RDFService rdfService) throws Exception;
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@ -386,25 +378,38 @@ public class CachingRDFServiceExecutor<T> {
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* Affinity class that serializes background processing for tasks given the same affinity
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*/
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public static class Affinity {
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private int maxThreads = 1;
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private final int maxThreads = 1;
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static class ThreadTimers {
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ThreadTimers(long started, long expectedDuration) {
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this.started = started;
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this.expectedDuration = expectedDuration;
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}
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final long started;
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final long expectedDuration;
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}
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// Map of executing threads, and the time they expect to need to execute
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private Map<Thread, Long> threadToExecutionTime = new HashMap<>();
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private Set<Thread> executingThreads = new HashSet<>();
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private final Map<Thread, ThreadTimers> threadToExecutionTime = new HashMap<>();
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private final Set<Thread> executingThreads = new HashSet<>();
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/**
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* Called by a background thread to determine if it is allowed to start
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* @param expectedExecutionTime time that the thread expects to take (usualling the last execution time)
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* @param expectedExecutionTime time that the thread expects to take (usually the last execution time)
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*/
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private void requestStart(long expectedExecutionTime) {
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Thread executingThread = Thread.currentThread();
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// Ask if the task needs to be queued
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if (queueThis(Thread.currentThread(), expectedExecutionTime)) {
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if (queueThis(executingThread, expectedExecutionTime)) {
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// Synchronize the thread to call wait
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synchronized (Thread.currentThread()) {
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synchronized (executingThread) {
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try {
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// Make the thread wait until it is notified to continue
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Thread.currentThread().wait();
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executingThread.wait();
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} catch(InterruptedException e) {
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// No need to execute
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}
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}
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}
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@ -426,7 +431,7 @@ public class CachingRDFServiceExecutor<T> {
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return false;
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} else {
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// Add the thread to the map
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threadToExecutionTime.put(thread, time);
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threadToExecutionTime.put(thread, new ThreadTimers(System.currentTimeMillis(), time));
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// Let the caller know that we are queued
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return true;
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@ -447,25 +452,46 @@ public class CachingRDFServiceExecutor<T> {
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while (threadToExecutionTime.size() > 0 && executingThreads.size() < maxThreads) {
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Thread nextToRelease = null;
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long executionTime = -1;
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long started = -1;
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long current = System.currentTimeMillis();
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boolean favourStartTime = false;
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// Find the thread that expects to take the least time
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for (Thread thread : threadToExecutionTime.keySet()) {
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long thisTime = threadToExecutionTime.get(thread);
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ThreadTimers thisThreadTimer = threadToExecutionTime.get(thread);
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// If there are threads that have been waiting over 2 seconds, favour the oldest thread
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if (thisThreadTimer.started + 2000 < current) {
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favourStartTime = true;
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}
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if (nextToRelease == null) {
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nextToRelease = thread;
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executionTime = thisTime;
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} else if (thisTime < executionTime) {
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nextToRelease = thread;
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executionTime = thisTime;
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executionTime = thisThreadTimer.expectedDuration;
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started = thisThreadTimer.started;
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} else {
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if (favourStartTime) {
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// Find the oldest thread
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if (thisThreadTimer.started < started) {
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nextToRelease = thread;
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executionTime = thisThreadTimer.expectedDuration;
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started = thisThreadTimer.started;
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}
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} else if (thisThreadTimer.expectedDuration < executionTime) {
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nextToRelease = thread;
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executionTime = thisThreadTimer.expectedDuration;
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started = thisThreadTimer.started;
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}
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}
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}
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// Synchronize on the thread we are releasing, and notify it to continue
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synchronized (nextToRelease) {
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// Notify the Thread we are releasing to continue
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if (nextToRelease != null) {
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threadToExecutionTime.remove(nextToRelease);
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executingThreads.add(nextToRelease);
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nextToRelease.notify();
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synchronized (nextToRelease) {
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nextToRelease.notifyAll();
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}
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}
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}
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}
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