com.google.gerrit.server.project.ProjectCacheClock Maven / Gradle / Ivy
// Copyright (C) 2012 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.server.project;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import com.google.gerrit.server.config.ConfigUtil;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import org.eclipse.jgit.lib.Config;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
/** Ticks periodically to force refresh events for {@link ProjectCacheImpl}. */
@Singleton
public class ProjectCacheClock {
private volatile long generation;
@Inject
public ProjectCacheClock(@GerritServerConfig Config serverConfig) {
this(checkFrequency(serverConfig));
}
public ProjectCacheClock(long checkFrequencyMillis) {
if (checkFrequencyMillis == Long.MAX_VALUE) {
// Start with generation 1 (to avoid magic 0 below).
// Do not begin background thread, disabling the clock.
generation = 1;
} else if (10 < checkFrequencyMillis) {
// Start with generation 1 (to avoid magic 0 below).
generation = 1;
ScheduledExecutorService executor = Executors.newScheduledThreadPool(
1,
new ThreadFactoryBuilder()
.setNameFormat("ProjectCacheClock-%d")
.setDaemon(true)
.setPriority(Thread.MIN_PRIORITY)
.build());
executor.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
// This is not exactly thread-safe, but is OK for our use.
// The only thread that writes the volatile is this task.
generation = generation + 1;
}
}, checkFrequencyMillis, checkFrequencyMillis, TimeUnit.MILLISECONDS);
} else {
// Magic generation 0 triggers ProjectState to always
// check on each needsRefresh() request we make to it.
generation = 0;
}
}
long read() {
return generation;
}
private static long checkFrequency(Config serverConfig) {
String freq = serverConfig.getString("cache", "projects", "checkFrequency");
if (freq != null
&& ("disabled".equalsIgnoreCase(freq) || "off".equalsIgnoreCase(freq))) {
return Long.MAX_VALUE;
}
return TimeUnit.MILLISECONDS.convert(
ConfigUtil.getTimeUnit(serverConfig,
"cache", "projects", "checkFrequency",
5, TimeUnit.MINUTES), TimeUnit.MINUTES);
}
}