How to access custom Java classes from RingoJS?

Question

I have created a few classes in Java and have combined them into a single package in the 'org' namespace. How do I access them from RingoJS?

Must I copy the package into the 'src/org' directory in Ringo or do I have to modify the classpath dynamically from the script?

Answer 1

I finally figured out how to access custom Java classes in RingoJS. I must have been really stupid to have never seen it right in front of my eyes before.

In Rhino, to access custom Java classes you need to add them to your Java classpath. This can be tedious, especially when an end user without any knowledge about programming tries to install a CommonJS package which requires specific Java classes to be in the classpath. Correct me if I'm wrong. Package managers like Tusk might be able to do that for you, and I would really appreciate it if you would notify me about such a feature. However, as far as I know it's the end users responsibility to add the Java classes and/or jar files to the classpath.

RingoJS simplifies this a great deal. It provides a global function addToClasspath(pathName) which adds a JAR file or directory to the classpath. Thus we may have a Java package or JAR file in the root directory of the CommonJS package and use the addToClasspath function in the JavaScript file itself to automatically add it to the classpath. In addition, all JAR files in the RingoJS lib directory are included in the classpath by default. This simplifies matters a great deal.

For programming purposes you may add JAR files to the RingoJS lib directory. However, I wouldn't recommend it. To reduce coupling and keep the RingoJS lib directory clean (preventing future namespace problems); and to make installation for the end user easier, I suggest using the addToClassPath function. Perhaps it should be implemented in other Rhino-based CommonJS implementations as well.