public Object evaluateScript(String execName) throws BuildException 
{
        checkLanguage();
        ClassLoader origLoader = replaceContextLoader();
        try {
            BSFManager m = createManager();
            declareBeans(m);
            // execute the script
            if (engine == null) {
                return m.eval(getLanguage(), execName, 0, 0, getScript());
            }
            return engine.eval(execName, 0, 0, getScript());
        } catch (BSFException be) {
            throw getBuildException(be);
        } finally {
            restoreContextLoader(origLoader);
        }
}

Evaluate the script.

 public  void executeScript(String execName) throws BuildException 
{
        checkLanguage();
        ClassLoader origLoader = replaceContextLoader();
        try {
            BSFManager m = createManager();
            declareBeans(m);
            // execute the script
            if (engine == null) {
                m.exec(getLanguage(), execName, 0, 0, getScript());
            } else {
                engine.exec(execName, 0, 0, getScript());
            }
        } catch (BSFException be) {
            throw getBuildException(be);
        } finally {
            restoreContextLoader(origLoader);
        }
}

Do the work.

 public String getManagerName() 
{
        return "bsf";
}

Get the name of the manager prefix.

 public boolean supportsLanguage() 
{
        Hashtable table = (Hashtable) ReflectUtil.getField(
            new BSFManager(), "registeredEngines");
        String engineClassName = (String) table.get(getLanguage());
        if (engineClassName == null) {
            getProject().log(
                "This is no BSF engine class for language '"
                + getLanguage() + "'",
                Project.MSG_VERBOSE);
            return false;
        }
        try {
            getScriptClassLoader().loadClass(engineClassName);
            return true;
        } catch (Throwable ex) {
            getProject().log(
                "unable to create BSF engine class for language '"
                + getLanguage() + "'",
                ex,
                Project.MSG_VERBOSE);
            return false;
        }
}

Check if bsf supports the language.