Compiling the OpenCms core

This page covers the build process for OpenCms versions since 7.0.2. For older versions please refer to this page.

OpenCms provides a source code distribution that you can use to build the OpenCms core. This is only needed if you want to add your own core extensions. To develop the usual kind of website functionality, you should use the OpenCms module mechanism which is much easier to start with and also better documented. Before even considering starting to work on the core, you definitely should have written some OpenCms modules to understand the separation between a module and and a core extension.

The OpenCms core comes with the best possible documentation: The source code itself ;-) This is really not something for the novice Java developer. However, if you have some experience in Java, Java Servlets, JDBC, and XML in general you might take a look. As said before, you should also have already a firm understanding of the OpenCms module API.

Since this is rather deep stuff targeted rather at experts than at beginners, we will not explain every detail of the process. You have been warned.

Step 1: Have Ant installed

Note: In case you are using the Eclipse Platform for development, you don't need an installation of Ant, it is included in Eclipse.

Apache Ant is a Java based build tool. In theory it is kind of like make without make's wrinkles. You need Ant version 1.6 or later to build the OpenCms core. Ant is part of the Jarkarta Apache Project and can be downloaded here. Please check the Ant documentation to make sure you understand the basic principles behind Ant.

Ant installation is described in the Ant manual. It requires that you have set up your path to Java correctly. Make sure Ant runs before proceeding.

Step 2: Get the OpenCms Source distribution

Check out the latest OpenCms source distribution from the repository as described here. It contains all classes necessary to build the OpenCms core. You will then end up with the following structure in your work directory:

/opencms
    /lib/compile     <= Necessary libraries for compilation
    /lib/runtime     <= Necessary runtime libraries
    /modules         <= Module resources
    /src             <= OpenCms Core source tree
    /src-components  <= Component sources (Upload applet, Ant tasks)
    /src-modules     <= Module sources
    /src-setup       <= Setup/Update Wizard sources
    /test            <= JUnit test sources
    /webapp          <= OpenCms web application
    /webapp/setup    <= Setup Wizard web application
    /webapp/update   <= Update Wizard web application
    build.xml        <= Ant build script

Step 3: Build the source by starting Ant

Ok this is the easy part. Call up a commandline, move to the /opencms directory (where the file build.xml resides) of the OpenCms source tree. In your commandline, enter the following:

ant war

That's it! This will build a complete OpenCms distribution. This will create a new /buildcms directory (at the same level as the /opencms directory) and will look like this after Ant is finished:

/opencms  <= Unchanged
/buildcms <= New created directory
   /build <= Contains the compiled OpenCms classes and jar files
   /zip   <= The OpenCms distribution files will be placed here

The final result of the compilation will be a ZIP file which will be placed in the /zip directory. This ZIP is exactly the same layout as the OpenCms binary distributions, so it will contain the opencms.war archive.

Step 4: Install your new version

Now that you have your new OpenCms binary distribution, you simply need to follow the Server installation guide for your server setup. Please make sure you don't mess up any existing installation. Best have a separate machine that is used only for testing and development.

Other Ant targets

There are several more targets in the build.xml that might be useful for you. Here's a short overview:

• Ant target: war
  This creates the opencms.war, but does not create the binary distribution ZIP file.
• Ant target: srcdist
  This generates the source distribution ZIP file. Like the one you downloaded in step 2.
• Ant target: tomcat.update
  This is useful if you really are in developing core extensions. Provided that OpenCms runs on your machine using Tomcat (and that you have all environment variables set up, esp. TOMCAT_HOME or CATALINA_HOME), calling this target will have Ant updating the OpenCms classes on your machine. This is done by replacing the files in the Tomcat webapps/opencms directory. If you have renamed opencms.war, or if your Tomcat is not installed the usual way, you will have to overwrite some build properties, like app.name.