Installation

This document describes the standard installation. Please see the reference guide for possible variations.

Prerequisites

Web container (Jakarta-Tomcat)

You must install Jakarta-Tomcat: this is the only supported container for the web-application. AstroGrid recommends Tomcat v5.0.28. V5.5.x is not suitable.

Tomcat roles

You will need to use Tomcat's administration features to configure the web-application. You should configure Tomcat with a local user-name that has the admin and manager roles.

Naming the web-application context

You must choose a name for the "context" in which the web-application runs. This name will become part of the URLs for your HTTP-CEC web-service and the web pages of your JC-CEC web-application. E.g., if you name the web-application context "JC-CEC-1", the URLs will be of the form

http://your.server.address:8080/JC-CEC-1/
http://your.server.address:8080/JC-CEC-1/services/CommonExecutionConnectorService 
respectively.

Java class for the applications

For this kind of CEC, you must provide the applications as a compiled Java-class. When correctly configured, the CEC will present every static method of that class as a CEA application. The methods that become applications can only have primitive arguments or arguments of type java.lang.String: custom objects as arguments are not supported. Each such method should return its result in the Java sense (i.e. don't write the result to standard output). Don't include a Main method in the class; that will show up as a separate, broken application in the CEA. See the reference manual for more advice on providing Java-class applications.

Related components

FileStore

Your CEC works with AstroGrid's FileManager component to read and write files in VOSpace. The details of which stores to use are set by the clients of the web-application in requests to the CEC web-service. You do not need to supply your own FileManager to operate the CEC web-application.

Registry

Your web application uses an IVOA resource-registry to publicize its capabilities. You must have access to a registry in which you can publish your resources and a registry from which your CEC can search for resources at run-time.

The publishing registry and the searchable registry may be the same service. In this case, you will typically use an external registry. As an alternative, you may choose to run a local publishing registry. This makes it easier to publish and maintain groups of services on your site and also helps you establish a "brand" for your services by associating them with your own publishing authority. If you want to run a publishing registry, then you should install and set up the AstroGrid registry component before setting up your CEC.

Installation procedure

  1. Obtain a copy of the WAR file for the CEC from the AstroGrid software site. See the guide to downloading for details.
  2. Rename the WAR file to match the chosen name of the web-application context; e.g. JC-CEC-1.war if the context is JC-CEC-1 as in the example above.
  3. Copy your renamed WAR file into the webapps sub-directory of your Tomcat installation. Wait a few seconds. Tomcat notices the WAR file, unpacks the web-application into a sub-directory tree in the webapps directory and starts the web-application.
  4. Check that the web-application has started correctly by going, with a web-browser, to the root of the web application (http://your.server.address:8080/JC-CEC-1/ in the example above). If no web-page is returned, then there is a problem with the WAR.
  5. Add the classes for your Java application to Tomcat. If you have them as separate .class files then put them in the common/classes directory within Tomcat. If you have them in a JAR file, put the jar in the common/lib directory within Tomcat.
  6. Restart Tomcat so that it notices the new classes and jars.
  7. Now set up your web-application by following the instructions in the configuration guide.