领略Quartz源码架构之美——源码实弹之Scheduler(二
2018-11-19 本文已影响0人
向光奔跑_
本章阅读收获:可了解Quartz框架中的Scheduler部分源码
继上一节内容
上一节上我们讲到了StdSchedulerFactory.getScheduler()中的initialize()方法，下面我们继续来讲getScheduler()这块内容。
回顾getScheduler()代码块源码
/**
* 获取任务Schedule
*/
@Override
public Scheduler getScheduler() throws SchedulerException {
//第一步加载配置文件，System的properties覆盖前面的配置
if (cfg == null) {
initialize();
}
//本地存储Schedule任务,注：SchedulerRepository是单例模式
SchedulerRepository schedRep = SchedulerRepository.getInstance();
//从缓存中查询获取Schedule任务，任务名称从配置中获取，若无指定，则默认指定QuartzScheduler
Scheduler sched = schedRep.lookup(getSchedulerName());
//判断若存在且已停止运行，则从缓存中移除
if (sched != null) {
if (sched.isShutdown()) {
schedRep.remove(getSchedulerName());
} else {
return sched;
}
}
//开始很多初始化对象
sched = instantiate();
return sched;
}
在上一讲中我们把instantiate()方法解析完成，下面我们开始讲SchedulerRepository。
SchedulerRepository源码解析
package org.quartz.impl;
import java.util.Collection;
import java.util.HashMap;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
/**
* <p>
* 保持对调度器实例的引用-确保唯一性，以及
* 防止垃圾收集，并允许“全球”查找-所有在一个
* 类加载器空间。
* </p>
*
* <person>
* 调度程序库，采用单例模式存储任务调度Schedule
* </person>
* @author James House
*/
public class SchedulerRepository {
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Data members.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
private HashMap<String, Scheduler> schedulers;
private static SchedulerRepository inst;
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Constructors.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
private SchedulerRepository() {
schedulers = new HashMap<String, Scheduler>();
}
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Interface.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
public static synchronized SchedulerRepository getInstance() {
if (inst == null) {
inst = new SchedulerRepository();
}
return inst;
}
/**
* 绑定新的任务调度器
*/
public synchronized void bind(Scheduler sched) throws SchedulerException {
if ((Scheduler) schedulers.get(sched.getSchedulerName()) != null) {
throw new SchedulerException("Scheduler with name '"
+ sched.getSchedulerName() + "' already exists.");
}
schedulers.put(sched.getSchedulerName(), sched);
}
/**
* 移除新的任务调度器
*/
public synchronized boolean remove(String schedName) {
return (schedulers.remove(schedName) != null);
}
/**
* 查询新的任务调度器
*/
public synchronized Scheduler lookup(String schedName) {
return schedulers.get(schedName);
}
/**
* 查询所有任务调度器
*/
public synchronized Collection<Scheduler> lookupAll() {
return java.util.Collections
.unmodifiableCollection(schedulers.values());
}
}
可以看到这里其实就是使用内存持久化任务调度器，非常简单易懂，我们这不做展开。我们直接进入最重要、最核心的instantiate()方法（不要和之前的initialize方法搞错呦！！！）
instantiate源码解析
由于这个过程非常的漫长，所以我们需要改一下之前的套路，需要逐个击破，分而破之。下面是开头的源码：
/**
* 开始初始化各种所需对象实例
* @return
* @throws SchedulerException
*/
private Scheduler instantiate() throws SchedulerException {
if (cfg == null) {
initialize();
}
if (initException != null) {
throw initException;
}
//任务配置存储
JobStore js = null;
//线程池
ThreadPool tp = null;
//实际调度器
QuartzScheduler qs = null;
//数据库连接管理器
DBConnectionManager dbMgr = null;
//自动生成id类
String instanceIdGeneratorClass = null;
//配置文件
Properties tProps = null;
//用户事务定位
String userTXLocation = null;
//包装任务进事务中
boolean wrapJobInTx = false;
//是否自动
boolean autoId = false;
//服务器延迟
long idleWaitTime = -1;
// 15 secs 存储失败重试时间
long dbFailureRetry = 15000L;
//类加载帮助类
String classLoadHelperClass;
//任务工厂类
String jobFactoryClass;
//线程执行器
ThreadExecutor threadExecutor;
//调用程序库
SchedulerRepository schedRep = SchedulerRepository.getInstance();
// Get Scheduler Properties
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//PROP_SCHED_INSTANCE_NAME = org.quartz.scheduler.instanceName
//设置调度器名字，默认是QuartzScheduler
String schedName = cfg.getStringProperty(PROP_SCHED_INSTANCE_NAME,
"QuartzScheduler");
//PROP_SCHED_THREAD_NAME = org.quartz.scheduler.threadName
//设置调度器线程名字，默认是调度器名字+_QuartzSchedulerThread
String threadName = cfg.getStringProperty(PROP_SCHED_THREAD_NAME,
schedName + "_QuartzSchedulerThread");
//DEFAULT_INSTANCE_ID = NON_CLUSTERED
//PROP_SCHED_INSTANCE_ID = org.quartz.scheduler.instanceId
String schedInstId = cfg.getStringProperty(PROP_SCHED_INSTANCE_ID,
DEFAULT_INSTANCE_ID);
//AUTO_GENERATE_INSTANCE_ID = AUTO
//这段if代码逻辑是判断是否用户是否设置自动生成scheduleinstanceId自动生成
//生成id的默认实现类是org.quartz.simpl.SimpleInstanceIdGenerator
if (schedInstId.equals(AUTO_GENERATE_INSTANCE_ID)) {
autoId = true;
instanceIdGeneratorClass = cfg.getStringProperty(
PROP_SCHED_INSTANCE_ID_GENERATOR_CLASS,
"org.quartz.simpl.SimpleInstanceIdGenerator");
}
// SYSTEM_PROPERTY_AS_INSTANCE_ID = SYS_PROP
//生成id的默认实现类是org.quartz.simpl.SystemPropertyInstanceIdGenerator
else if (schedInstId.equals(SYSTEM_PROPERTY_AS_INSTANCE_ID)) {
autoId = true;
instanceIdGeneratorClass =
"org.quartz.simpl.SystemPropertyInstanceIdGenerator";
}
//PROP_SCHED_USER_TX_URL = org.quartz.scheduler.userTransactionURL
userTXLocation = cfg.getStringProperty(PROP_SCHED_USER_TX_URL,
userTXLocation);
if (userTXLocation != null && userTXLocation.trim().length() == 0) {
userTXLocation = null;
}
// PROP_SCHED_CLASS_LOAD_HELPER_CLASS = org.quartz.scheduler.classLoadHelper.class
classLoadHelperClass = cfg.getStringProperty(
PROP_SCHED_CLASS_LOAD_HELPER_CLASS,
"org.quartz.simpl.CascadingClassLoadHelper");
//PROP_SCHED_WRAP_JOB_IN_USER_TX = org.quartz.scheduler.wrapJobExecutionInUserTransaction
wrapJobInTx = cfg.getBooleanProperty(PROP_SCHED_WRAP_JOB_IN_USER_TX,
wrapJobInTx);
//PROP_SCHED_JOB_FACTORY_CLASS = org.quartz.scheduler.jobFactory.class
jobFactoryClass = cfg.getStringProperty(
PROP_SCHED_JOB_FACTORY_CLASS, null);
//PROP_SCHED_IDLE_WAIT_TIME = org.quartz.scheduler.idleWaitTime
idleWaitTime = cfg.getLongProperty(PROP_SCHED_IDLE_WAIT_TIME,
idleWaitTime);
if(idleWaitTime > -1 && idleWaitTime < 1000) {
throw new SchedulerException("org.quartz.scheduler.idleWaitTime of less than 1000ms is not legal.");
}
//PROP_SCHED_DB_FAILURE_RETRY_INTERVAL = org.quartz.scheduler.dbFailureRetryInterval
dbFailureRetry = cfg.getLongProperty(PROP_SCHED_DB_FAILURE_RETRY_INTERVAL, dbFailureRetry);
if (dbFailureRetry < 0) {
throw new SchedulerException(PROP_SCHED_DB_FAILURE_RETRY_INTERVAL + " of less than 0 ms is not legal.");
}
//PROP_SCHED_MAKE_SCHEDULER_THREAD_DAEMON = org.quartz.scheduler.makeSchedulerThreadDaemon
boolean makeSchedulerThreadDaemon =
cfg.getBooleanProperty(PROP_SCHED_MAKE_SCHEDULER_THREAD_DAEMON);
//PROP_SCHED_SCHEDULER_THREADS_INHERIT_CONTEXT_CLASS_LOADER_OF_INITIALIZING_THREAD =
// org.quartz.scheduler.threadsInheritContextClassLoaderOfInitializer
boolean threadsInheritInitalizersClassLoader =
cfg.getBooleanProperty(PROP_SCHED_SCHEDULER_THREADS_INHERIT_CONTEXT_CLASS_LOADER_OF_INITIALIZING_THREAD);
//PROP_SCHED_BATCH_TIME_WINDOW = org.quartz.scheduler.batchTriggerAcquisitionFireAheadTimeWindow
long batchTimeWindow = cfg.getLongProperty(PROP_SCHED_BATCH_TIME_WINDOW, 0L);
//PROP_SCHED_MAX_BATCH_SIZE = org.quartz.scheduler.batchTriggerAcquisitionMaxCount
int maxBatchSize = cfg.getIntProperty(PROP_SCHED_MAX_BATCH_SIZE, 1);
//PROP_SCHED_INTERRUPT_JOBS_ON_SHUTDOWN = org.quartz.scheduler.interruptJobsOnShutdown
boolean interruptJobsOnShutdown = cfg.getBooleanProperty(PROP_SCHED_INTERRUPT_JOBS_ON_SHUTDOWN, false);
//PROP_SCHED_INTERRUPT_JOBS_ON_SHUTDOWN_WITH_WAIT = org.quartz.scheduler.interruptJobsOnShutdownWithWait
boolean interruptJobsOnShutdownWithWait = cfg.getBooleanProperty(PROP_SCHED_INTERRUPT_JOBS_ON_SHUTDOWN_WITH_WAIT, false);
//PROP_SCHED_JMX_EXPORT = org.quartz.scheduler.jmx.export
boolean jmxExport = cfg.getBooleanProperty(PROP_SCHED_JMX_EXPORT);
//PROP_SCHED_JMX_OBJECT_NAME = org.quartz.scheduler.jmx.objectName
String jmxObjectName = cfg.getStringProperty(PROP_SCHED_JMX_OBJECT_NAME);
//PROP_SCHED_JMX_PROXY = org.quartz.scheduler.jmx.proxy
boolean jmxProxy = cfg.getBooleanProperty(PROP_SCHED_JMX_PROXY);
//PROP_SCHED_JMX_PROXY_CLASS = org.quartz.scheduler.jmx.proxy.class
String jmxProxyClass = cfg.getStringProperty(PROP_SCHED_JMX_PROXY_CLASS);
//PROP_SCHED_RMI_EXPORT = org.quartz.scheduler.rmi.export
boolean rmiExport = cfg.getBooleanProperty(PROP_SCHED_RMI_EXPORT, false);
//PROP_SCHED_RMI_PROXY = org.quartz.scheduler.rmi.proxy
boolean rmiProxy = cfg.getBooleanProperty(PROP_SCHED_RMI_PROXY, false);
//PROP_SCHED_RMI_HOST = org.quartz.scheduler.rmi.registryHost
String rmiHost = cfg.getStringProperty(PROP_SCHED_RMI_HOST, "localhost");
//PROP_SCHED_RMI_PORT = org.quartz.scheduler.rmi.registryPort
int rmiPort = cfg.getIntProperty(PROP_SCHED_RMI_PORT, 1099);
//PROP_SCHED_RMI_SERVER_PORT = org.quartz.scheduler.rmi.serverPort
int rmiServerPort = cfg.getIntProperty(PROP_SCHED_RMI_SERVER_PORT, -1);
//PROP_SCHED_RMI_CREATE_REGISTRY = org.quartz.scheduler.rmi.createRegistry
String rmiCreateRegistry = cfg.getStringProperty(
PROP_SCHED_RMI_CREATE_REGISTRY,
//CREATE_REGISTRY_NEVER = never
QuartzSchedulerResources.CREATE_REGISTRY_NEVER);
//PROP_SCHED_RMI_BIND_NAME = org.quartz.scheduler.rmi.bindName
String rmiBindName = cfg.getStringProperty(PROP_SCHED_RMI_BIND_NAME);
if (jmxProxy && rmiProxy) {
throw new SchedulerConfigException("Cannot proxy both RMI and JMX.");
}
//MANAGEMENT_REST_SERVICE_ENABLED = org.quartz.managementRESTService.enabled
boolean managementRESTServiceEnabled = cfg.getBooleanProperty(MANAGEMENT_REST_SERVICE_ENABLED, false);
//MANAGEMENT_REST_SERVICE_HOST_PORT = org.quartz.managementRESTService.bind
String managementRESTServiceHostAndPort = cfg.getStringProperty(MANAGEMENT_REST_SERVICE_HOST_PORT, "0.0.0.0:9889");
//PROP_SCHED_CONTEXT_PREFIX = org.quartz.context.key
Properties schedCtxtProps = cfg.getPropertyGroup(PROP_SCHED_CONTEXT_PREFIX, true);
...
}
上面就是一些属性的加载，其实功能非常简单，就是从我们的配置文件中取出一些配置参数。具体的可以看下我的注释。
结束语
本文讲了instantiate（）的属性部分（好吧，其实就是水了一章），有些人可能会说为什么我要介绍的那么详细，主要还是可能本人有稍微一点强迫症，之前看别人源码都是一段一段的，就算读懂了他贴的代码的内容，但还是觉得心里不爽，说了那么多，其实就是不想让那些跟我一样的人（好吧，其实就是我自己）心里不爽而已~~~~
