| ylbtech-Quartz：Quartz |
Quartz is an open source organization OpenSymphony in Job scheduling field and an open source project , it can be combined with J2EE and J2SE applications can also be used alone . Quartz can be used to create simple or run ten, one hundred, or even tens of thousands of Jobs such a complex program. Jobs can be made standard Java components or EJBs . The latest version of Quartz Quartz 2.3.0.
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- Chinese name: extended Benitez formula
- English name: quartz
- Category: Open Source Project
- The latest version: Quartz 2.3.0
- Explained: written by java open source job scheduling framework
table of Contents
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Scheduling Simple
Quartz is an open source job scheduling framework written entirely in java. Do not let the term scare you job scheduling. Although Quartz framework incorporates many additional features, but in its simple form look, you will find it easy to use, you just can not stand! . Simply create a realization of
java class org.quartz.Job interface
. Job interface contains only way:
public void execute(JobExecutionContext context)
throws JobExecutionException;
Your Job class interface inside, adding some logic to execute () method.
Once you have configured Job implementation class schedule and set the schedule, Quartz will pay close attention to the remaining time
. When the scheduler determines that the job is to inform you of the time, Quartz framework calls execute on your Job implementation class (working class) () method and allowed to do what it should do. No need to report anything to the dispatcher or call any particular thing. Only perform tasks and to end the task. If you configure your job then is called again, Quartz framework will call it again at the right time.
The internal architecture
In terms of size, Quartz with most open-source framework similar.
Approximately 300 java classes and interfaces, and is organized into 12 packets
.
This may be the Apache Struts and about 325 and organized into classes and interfaces in the package 11 compared
. Despite the scale rarely used as a framework to measure the characteristics of quality, but the key here is that quartz contains many features, whether these functions and features set to become, or should become an open-source or non-open-source framework to judge the quality factor.
scheduler
Quartz framework
core scheduler
. The scheduler
is responsible for managing Quartz application run-time environment
. The scheduler is not doing all the work on their own, relying instead on some very important components in the framework. Quartz is not just a thread and thread management. To ensure scalability, Quartz-based architecture uses a multi-threaded. At startup, the initialization of a frame worker thread, this thread scheduler to perform a predetermined job. This is how Quartz can
run concurrently
principle of multiple jobs. Quartz-dependent set of loosely coupled
thread pool
management part to manage the thread environment. In this article, we will mention several times the thread pool management, but Quartz inside each object is configurable or customizable. So, for example, if you want to insert your own thread pool management facilities, I guess you will be able to!
Framework features
Quartz framework has a rich feature set. In fact, Quartz too many characteristics that can not be fully appreciated in one case, here are some interesting features, but do not have time to discuss in detail here.
Listeners and plug-ins
Everyone likes to listen and plug-ins
. Today, almost any open source framework for download, you will certainly find support these two concepts.
Listener is a java class you created when key events occur will receive a callback framework
. For example, when a job is scheduled, no scheduling or trigger termination and no longer triggered, these can be notified by setting your listeners. Quartz framework includes
a scheduler monitoring, operation and triggers monitor
. You can configure the monitor to work and trigger
a global listener is listening or job-specific and triggers
.
Once you have a specific monitor is called, you can use this technology to do some of the things you want to do in class listening inside. For example, if you want to send an e-mail each time a job is completed, you can use this logic written work which can also be written into the JobListener inside. Written JobListener way to force the use of
loosely coupled
facilitate the design on to do better.
Quartz is a new plug-in features, without having to modify the source code Quartz can be created and added to the Quartz framework. He wants to expand Quartz framework and no change to the timing of the submission Quartz development team and wait for a new version of the developer and design. If you are familiar with Struts
plug-in
, then you can fully understand the use of Quartz plug-ins.
Quartz can not meet its offers a limited extension points you need, might as well have extension points can be trimmed by using plug-ins.
Quartz Application Clusters
Quartz can be applied cluster , the cluster is horizontal or vertical cluster depends on your needs
. Clusters provide the following benefits:
· Scalability
High Availability
· Load Balancing
Quartz can make use of relational databases and JDBC support job storage cluster.
Terracotta extension quartz provides clustering capabilities without the need for database support
Related Tools
Quartz cron expression often used, can be used to generate foreign websites cronmaker auxiliary cron expression.
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