Quartz Examples

This project provides examples of Quartz Scheduler that demonstrate some of its features.

The Quartz Scheduler is a very flexible scheduling library. The easiest way to learn is to explore some the examples provided here, and then try something on your own. There are many configuration settings you can use to control the scheduler, and you can easily test any of these in a Java properties file to explore the features.

This project configured Quartz library with Logback as the logger, and default to INFO level to STDOUT for log messages. You may edit the src/main/resources/logback.xml to increase the level to "DEBUG" if you wish to see more activities in action by the scheduler.

The project also provided a default PostgreSQL database as backend storage. If you wish to test out the scheduler in any other DB, just create similar configuration and change out the datasource configuration settings. You will find many quartz configuration examples under src/main/resources/zemian/quartz/examples folder.

Requirements

• Java 7 or higher

• Maven 3.3 or higher

• Postgres 9 or higher

Setup Postgres Database

For convenience, there is a copy of schema script under db/tables_postgres.sql. For latest copy of this file, you should get it from the quartz project site.

To prepare Postgres DB for quartz using default 'postgres' user, try the following:

postgres# create database quartz;
postgres# \c quartz
postgres# \i /path/to/quartz-zemian-examples/db/tables_postgres.sql

Quartz Examples

This project provide a reusable QuartzServer program that can take any quartz properties configuration file and run it as a server. You can press CTRL+C keys on console to stop it.

RAM Scheduler

To run a quartz scheduler as a server using in memory storage, type the following:

mvn exec:java -Dexec.mainClass=zemian.quartz.examples.QuartzServer -DquartzConfig=zemian/quartz/examples/quartz.properties

Postgres DB Scheduler

To run a quartz scheduler as a server connecting to postgres DB, type the following:

mvn exec:java -Dexec.mainClass=zemian.quartz.examples.QuartzServer -DquartzConfig=zemian/quartz/examples/quartz-postgres.properties

Inserting Jobs Programmatically Using API

There are many ways to insert jobs into scheduler. One way is programmatically using the API. Quartz uses the same org.quartz.Scheduler interface as the server for inserting job. You just need to ensure NOT to start the scheduler instance since you are writing only a "client" program. Simply use the API to insert/update jobs and then exit.

Here is an example of a client program that insert couple running jobs. Note that you can use the same configuration file you pass to "server" side so you connect to the same datasource store.

You should create a new client program for each set of new jobs that you want to create and insert.

mvn exec:java -Dexec.mainClass=zemian.quartz.examples.QuartzClient -DquartzConfig=zemian/quartz/examples/quartz-postgres.properties

Inserting Jobs Using Scripts

Writing Java client is not too hard, but it requires you to compile the code. Simple clients like above is a good fit for scripting. You can easily run script engine using Java platform. We have added Groovy script language to the project dependency, and you may try out our demo as documented here.

Note	The scripts/rungroovy.sh is for MacOS or Linux only. For Windows, you would need to fix the classpath and try to run it with Cygwin.

Groovy Scripting

Step 1: Setup jars the first time

mvn dependency:copy-dependencies

Step 2: Run any scripts

CONFIG=zemian/quartz/examples/quartz-postgres.properties scripts/rungroovy.sh scripts/listJobs.groovy

Here is how we can pause and resume a job

CONFIG=zemian/quartz/examples/quartz-postgres.properties scripts/rungroovy.sh scripts/pauseJob.groovy HelloJob
CONFIG=zemian/quartz/examples/quartz-postgres.properties scripts/rungroovy.sh scripts/resumeJob.groovy HelloJob

Writing Dynamic Job

Quartz job is implemented using Java, and you would need to recompile the code whenever you change the code. Often time we have small job that can be done using simple scripting. The simple syntax of Groovy for writing dynamic job is a very powerful way to create new quartz job. Our project included a ScriptJob class that let you reference a script file and execute it at runtime. Here is an example:

Adding a HelloScriptJob

CONFIG=zemian/quartz/examples/quartz-postgres.properties scripts/rungroovy.sh scripts/newDurableScriptJob.groovy HelloScriptJob `pwd`/scripts/jobs/HelloScriptJob.groovy
CONFIG=zemian/quartz/examples/quartz-postgres.properties scripts/rungroovy.sh scripts/newCronTrigger.groovy HelloScriptJob HourlyTrigger '0 0 * * * ?'