我是石英新手。我发现了@DisallowConcurrentExecutionquartz库提供的注释，文档说：'An annotation that marks a {@link Job} class as one that must not have multiple instances executed concurrently (where instance is based-upon a {@link JobDetail} definition - or in other words based upon a {@link JobKey}).'则DisallowConcurrentExecution.java写为：@Documented@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.TYPE)public @interface DisallowConcurrentExecution {}但是，我找不到实际处理同一作业不并发执行的实现。这对我来说是新的，所以有人可以帮助我解释内部实现逻辑。我试图查找用法，但只在课堂上找到了它MethodInvokingJobDetailFactoryBean.java
1 回答
泛舟湖上清波郎朗
TA贡献1818条经验 获得超3个赞
我不参与石英项目。我在这里的所有评论都来自我出于好奇而对此事的调查，可能会遗漏一些信息。
首先要知道的是，JobDetailImpl 将检查注释是否存在并在方法中提供此信息。
/**
* @return whether the associated Job class carries the {@link DisallowConcurrentExecution} annotation.
*/
public boolean isConcurrentExectionDisallowed() {
return ClassUtils.isAnnotationPresent(jobClass, DisallowConcurrentExecution.class);
}
然后你可以看到这个方法在系统的不同部分被检查。
例如，JobStoreSupport 在此处检查它，如果存在注释，则它会检查块状态：
if (job.isConcurrentExectionDisallowed() && !recovering) {
state = checkBlockedState(conn, job.getKey(), state);
}
这里是实际验证发生的地方，并让 Quartz 决定在该实例上运行或不运行作业。
org.quartz.impl.jdbcjobstore.JobStoreSupport#checkBlockedState
/**
* Determines if a Trigger for the given job should be blocked.
* State can only transition to STATE_PAUSED_BLOCKED/BLOCKED from
* PAUSED/STATE_WAITING respectively.
*
* @return STATE_PAUSED_BLOCKED, BLOCKED, or the currentState.
*/
protected String checkBlockedState(
Connection conn, JobKey jobKey, String currentState)
throws JobPersistenceException {
// State can only transition to BLOCKED from PAUSED or WAITING.
if ((!currentState.equals(STATE_WAITING)) &&
(!currentState.equals(STATE_PAUSED))) {
return currentState;
}
try {
List<FiredTriggerRecord> lst = getDelegate().selectFiredTriggerRecordsByJob(conn,
jobKey.getName(), jobKey.getGroup());
if (lst.size() > 0) {
FiredTriggerRecord rec = lst.get(0);
if (rec.isJobDisallowsConcurrentExecution()) { // OLD_TODO: worry about failed/recovering/volatile job states?
return (STATE_PAUSED.equals(currentState)) ? STATE_PAUSED_BLOCKED : STATE_BLOCKED;
}
}
return currentState;
} catch (SQLException e) {
throw new JobPersistenceException(
"Couldn't determine if trigger should be in a blocked state '"
+ jobKey + "': "
+ e.getMessage(), e);
}
}
添加回答
举报
0/150
提交
取消