Apache Ivy

Almost all Java projects, apart from the most trivial ones have dependencies. These dependencies could either be on other projects or third-party libraries. Managing these dependencies can be extremely time-consuming and distracting from the primary focus of the project. Apache Ivy is a tool for managing library dependencies. Ivy neatly fills the gap by providing an easily configurable and automated dependency management system. Further, Ivy supports transitive dependencies management. Hence all we need to do is declare our main dependencies and Ivy automatically fetches all the sub dependencies along with the main dependencies from a public location such as the Maven 2 repository.

Installation

Ivy is designed to work with Ant, wherein Ant is used to run the build tasks and Ivy is used to resolve, retrieve and manage the dependencies. The simplest way to get started is to copy the Ivy jar file to the Ant lib (ANT_HOME/lib) directory.

Configure ivy.xml

The ivy.xml configuration file is the main file that is used to describe our dependencies. Below is an example of a configuration file that states two main dependencies, Hibernate and the C3P0 library.

<ivy-module version="2.0">
    <info organisation="techvj" module="ivy-test" />
    <dependencies>
        <dependency org="org.hibernate" name="hibernate" rev="3.2.6.ga" />
        <dependency org="c3p0" name="c3p0" rev="0.9.1.2" />
    </dependencies>
</ivy-module>

Integrate With Ant

The final step is to integrate the Ivy dependency resolution process with our Ant build process. Following is an example of a build.xml file with the retrieve task defined:

<project xmlns:ivy="antlib:org.apache.ivy.ant" name="hello-ivy" default="retrieve">
    ...
    <target name="retrieve" description="">
        <ivy:retrieve />
    </target>
</project>

On running the above Ant build, Ivy retrieves the Hibernate and C3P0 libraries and all of their dependencies to the local machine. The retrieved libraries are stored in a cache and not downloaded again on successive invocations. Apache Ivy is a great tool in a Java developer's toolbox for managing library dependencies.

Displaying Javadocs in Subversion

Javadocs are an essential component of any Java project. It is a convenient way for a developer to gain an understanding of the API and the prescribed ways to use it. This is especially true when hosting open source projects on Google Code or Sourceforge. Subversion is increasingly used as a revision control system to host source code and other project related artifacts. Google Code uses Subversion exclusively while Sourceforge provides it as an option. At times, for the convenience of hosting and to centralize resources it may be required to host the Javadocs in Subversion and access them via a browser. When using Eclipse as the IDE, connecting to a Subversion server is simple through the Subclipse plugin.

On successfully committing the Javadocs to the server and viewing the exported pages through a browser, we notice that the pages display in text and are not rendered as normal HTML pages by the browser (Screenshot). The reason behind this is that the MIME type for the pages is set to text/plain and must be changed to text/html. This can be achieved through the Eclipse UI by applying the MIME type to the svn:mime-type property on the root directory of the Javadocs. The Set property recursively option must be checked to ensure that all the pages under subdirectories are also updated with the correct type.

The last change is to update the MIME type of stylesheet.css to text/css. The Javadocs in Subversion can now be viewed successfully through a browser (Screenshot).