| // 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); |
| } |
| } |