Question

Could anyone say me, how should I use an existing Java object in a JRuby script?

I know how I can create a new instance of a Java class in JRuby, but in my case I have already an instance in Java and I want to check/modify some properties of it in my JRuby script.

//Java

public class MyClass 
{
private int size;

public int getSize() {
    return size;
}

public void setSize(int size) {
    this.size = size;
}
}

//...

MyClass myClass = new MyClass();
myClass.setSize(5);

//...

String script = "..????.."
ScriptingContainer rubyContainer = new ScriptingContainer();
rubyContainer.runScriptlet(script);

What should I write into the script variable to check and modify the size property like this:

if (myClass.getSize() > 3)
    myClass.setSize(10)
else
    myClass.setSize(0);

After the modification I’d like to be able to use the new value of the property in my Java code.

Thanks a lot!

Answer 1

Straight from the javadoc of ScriptingContainer

The second example shows how to share variables between Java and Ruby. In this example, a local variable “x” is shared. […]

Example 2:

    ScriptingContainer container = new ScriptingContainer();
    container.put("x", 12345);
    container.runScriptlet("puts x.to_s(2)");