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Code Issues Projects Releases Wiki Activity

Randomise next polling interval after pollNow().

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This commit is contained in:
akwizgran
2016-02-22 13:22:23 +00:00
parent 5ce8927477
commit 681ec080e1
1 changed files with 36 additions and 11 deletions
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47
briar-core/src/org/briarproject/plugins/PollerImpl.java
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@@ -1,11 +1,15 @@
package org.briarproject.plugins;
import org.briarproject.api.TransportId;
import org.briarproject.api.lifecycle.IoExecutor;
import org.briarproject.api.plugins.ConnectionRegistry;
import org.briarproject.api.plugins.Plugin;
import org.briarproject.api.system.Timer;
import java.security.SecureRandom;
import java.util.Map;
import java.util.TimerTask;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executor;
import java.util.logging.Logger;
@@ -20,14 +24,19 @@ class PollerImpl implements Poller {
private final Executor ioExecutor;
private final ConnectionRegistry connectionRegistry;
private final SecureRandom random;
private final Timer timer;
private final Map<TransportId, PollTask> tasks;
@Inject
PollerImpl(@IoExecutor Executor ioExecutor,
ConnectionRegistry connectionRegistry, Timer timer) {
ConnectionRegistry connectionRegistry, SecureRandom random,
Timer timer) {
this.ioExecutor = ioExecutor;
this.connectionRegistry = connectionRegistry;
this.random = random;
this.timer = timer;
tasks = new ConcurrentHashMap<TransportId, PollTask>();
}
public void stop() {
@@ -35,17 +44,28 @@ class PollerImpl implements Poller {
}
public void addPlugin(Plugin p) {
schedule(p, true);
// Randomise first polling interval
schedule(p, randomise(p.getPollingInterval()), false);
}
private void schedule(Plugin plugin, boolean randomise) {
long interval = plugin.getPollingInterval();
// Randomise intervals at startup to spread out connection attempts
if (randomise) interval = (long) (interval * Math.random());
timer.schedule(new PollTask(plugin), interval);
public void pollNow(Plugin p) {
// Randomise next polling interval
schedule(p, 0, true);
}
public void pollNow(final Plugin p) {
private int randomise(int interval) {
return (int) (interval * random.nextDouble());
}
private void schedule(Plugin p, int interval, boolean randomiseNext) {
// Replace any previously scheduled task for this plugin
PollTask task = new PollTask(p, randomiseNext);
PollTask replaced = tasks.put(p.getId(), task);
if (replaced != null) replaced.cancel();
timer.schedule(task, interval);
}
private void poll(final Plugin p) {
ioExecutor.execute(new Runnable() {
public void run() {
if (LOG.isLoggable(INFO))
@@ -58,15 +78,20 @@ class PollerImpl implements Poller {
private class PollTask extends TimerTask {
private final Plugin plugin;
private final boolean randomiseNext;
private PollTask(Plugin plugin) {
private PollTask(Plugin plugin, boolean randomiseNext) {
this.plugin = plugin;
this.randomiseNext = randomiseNext;
}
@Override
public void run() {
pollNow(plugin);
schedule(plugin, false);
tasks.remove(plugin.getId());
int interval = plugin.getPollingInterval();
if (randomiseNext) interval = randomise(interval);
schedule(plugin, interval, false);
poll(plugin);
}
}
}