Introducing the Quartz Web Application

The early developers of the Quartz framework realized that a GUI would be necessary for a certain group of users. Several years ago, a Web application was created that could be used to manage the Quartz framework. There has been quite a bit of development over the years, but, arguably, it has been sporadic.

Lately there has been an increased call for the application to be updated and supported, and it's starting to draw new developers who are willing to work on it and keep it up-to-date. The application is known as the Quartz Web application.

Screenshots of the Quartz Web Application

The upper-left side of the main screen in the Quartz Web application presents a list of features that are available (see Figure 13.4).

Figure 13.4. The main screen of the Quartz Web application

Figure 13.5 shows the Scheduler Control screen, which enables you to start, stop, and pause the Scheduler.

Figure 13.5. The Scheduler Control screen contains Scheduler-management features.

 

Downloading and Building the Quartz Web Application

The Quartz Web application is part of the Quartz source repository on OpenSymphony. It used to be housed on SourceForge, but it has recently moved over to its new home. The old site was located at http://sourceforge.net/projects/quartz; the new site (including the Quartz Web application) can be found at www.opensymphony.com/quartz/cvs.action.

Currently, there is no binary release of the Web application, and the standard Quartz download does not include the Web application, although the maintainers of the application have said they will have a build set up early 2006. For now, you need to download the Quartz source tree and build the Web application using the Ant build file located in the quartz/webapp directory.

To download Quartz from CVS, you need an account on the java.net site because anonymous access is not permitted. From a command line where you want to download the source tree to, type this:

cvs -d :pserver:[username]@cvs.dev.java.net:/cvs login
cvs -d :pserver:[username]@cvs.dev.java.net:/cvs checkout quartz
cvs -d :pserver:[username]@cvs.dev.java.net:/cvs checkout opensymphony

Quartz Requires OpenSymphony Source

OpenSymphony projects are practicing continuous integration. This means that projects have tighter but supportive dependencies on one another. You also must download the OpenSymphony source for Quartz to build successfully. Use the previous checkout command and substitute opensymphony for quartz. You should execute this command from the same place you executed the checkout for Quartz.

After you have downloaded the Quartz and OpenSymphony source, you can build Quartz from the quartz directory, but you also can build the Web application from the webapp directory underneath quartz. Change directories to webapp and type ant.

Installing the Quartz Web Application

When you have successfully built the Web application, there should be a quartz.war file created in the webapp/dist directory. Deploy this Web Archive (WAR) file into a container of your choice.

Not all Containers are Created Equal

We should point out that although the various Servlet and JSP specifications are designed to make it easier to move applications from one container to another, vendors sometimes fall short. At a minimum, we can say that each vendor interprets the specifications differently.

Some Quartz users have reported issues with deploying the Quartz Web application as a WAR file into WebLogic 8.1 and particular versions of WebSphere. If you're using Tomcat, you generally won't have many problems, but you might face some challenges with other containers. If you do encounter some trouble, try deploying the application in an exploded format instead of as a WAR.

 

Configuring and Running the Quartz Web Application

Now that the WAR file is deployed, fire it up in your Web browser. For Tomcat, the default URL is http://localhost:8080/quartz/. From the home page, you have options to manage the Scheduler, jobs, triggers, and logging.

All the menu options on the home page are secured. A new security filter was added in the latest release to mimic container-managed security. This means that you can call HttpServletRequest.getRemoteUser() and HttpRequest.isUserInRole() just like you can with container-managed security. Users are defined in the SecurityFilter-config.xml file. By default, it contains one user, quartz, with the password quartz. You can add your users to the SecurityFilter-config.xml file or simply extend org.securityfilter.realm.SecurityRealmInterface to provide a Security Realm to suit your needs.

Start by selecting the Scheduler Control menu item and, when prompted, sign in as user quartz. A test Scheduler is preconfigured with the Quartz Web application, and it is your only choice on this page. Take a look inside quartzwebappconfig esources to see how the Scheduler is configured. There you'll find the now familiar quartz.properties file. The name in the dropdown list on the Scheduler Controller page is the org.quartz.scheduler.instanceName property from quartz.properties.

Click the Job Definitions menu next. There you see three jobs: NativeJob, NoJob, and SendMailJob. If you looked around in the webappconfig esources folder, you've already guessed where jobs are defined: JobDefinitions.xml. This is loaded by the ContextLoaderServlet when the Quartz Web application starts. You can edit the JobDefinitions.xml file or provide your own job-definition files by changing the ContextLoaderServlet in the web.xml file.

If you're ready to run a job, you can select the Create link to the left of NativeJob on the Job Definitions page. You want to pick a native application that makes it very plain to see that your job has run. If you are on the Windows platform, you can use Notepad.exe. Start by giving the job a namepossibly Native Job Test. The name must be unique within the Scheduler. Next, type notepad in the command parameter and click Save. You should now see the Job Detail properties you just created.

Click the List Jobs menu item to see all the JobDetails on the Scheduler. Click the Execute link to the left of your JobDetail. A Notepad window pops opennot very practical, but you can imagine the possibilities. Have you been wondering as you read this book how you could leverage Quartz for non-Java jobs? Now you have your answer.

Now would be a good time to explore the Logging menu. Click Logging and scroll to the bottom of the listing. There you will find an entry for the job you just executed, along with other activity that has been occurring since you started your Scheduler.

Clicking the List all Triggers menu option shows you triggers that the Job Initializer loaded. Notice that there is no option to add a trigger from the Quartz Web application. Triggers must be declared within the job.xml files, which are also in the resources folder. The list of job.xml files is declared in the Job Initializer section of the quartz.properties file.

That's all there is to the Quartz Web application. All that is left to do is add your own jobs and triggers.


Scheduling in the Enterprise

Getting Started with Quartz

Hello, Quartz

Scheduling Jobs

Cron Triggers and More

JobStores and Persistence

Implementing Quartz Listeners

Using Quartz Plug-Ins

Using Quartz Remotely

Using Quartz with J2EE

Clustering Quartz

Quartz Cookbook

Quartz and Web Applications

Using Quartz with Workflow

Appendix A. Quartz Configuration Reference





Quartz Job Scheduling Framework(c) Building Open Source Enterprise Applications
Quartz Job Scheduling Framework: Building Open Source Enterprise Applications
ISBN: 0131886703
EAN: 2147483647
Year: N/A
Pages: 148
Similar book on Amazon

Flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net