org.jruby.RubyNil Java Examples

/**
 * Create a new JRuby-scripted object from the given script source.
 * @param scriptSource the script source text
 * @param interfaces the interfaces that the scripted Java object is to implement
 * @param classLoader the {@link ClassLoader} to create the script proxy with
 * @return the scripted Java object
 * @throws JumpException in case of JRuby parsing failure
 */
public static Object createJRubyObject(String scriptSource, Class<?>[] interfaces, ClassLoader classLoader) {
	Ruby ruby = initializeRuntime();

	Node scriptRootNode = ruby.parseEval(scriptSource, "", null, 0);
       IRubyObject rubyObject = ruby.runNormally(scriptRootNode);

	if (rubyObject instanceof RubyNil) {
		String className = findClassName(scriptRootNode);
		rubyObject = ruby.evalScriptlet("\n" + className + ".new");
	}
	// still null?
	if (rubyObject instanceof RubyNil) {
		throw new IllegalStateException("Compilation of JRuby script returned RubyNil: " + rubyObject);
	}

	return Proxy.newProxyInstance(classLoader, interfaces, new RubyObjectInvocationHandler(rubyObject, ruby));
}
 

/**
 * Create a new JRuby-scripted object from the given script source.
 * @param scriptSource the script source text
 * @param interfaces the interfaces that the scripted Java object is to implement
 * @param classLoader the {@link ClassLoader} to create the script proxy with
 * @return the scripted Java object
 * @throws JumpException in case of JRuby parsing failure
 */
public static Object createJRubyObject(String scriptSource, Class<?>[] interfaces, ClassLoader classLoader) {
	Ruby ruby = initializeRuntime();

	Node scriptRootNode = ruby.parseEval(scriptSource, "", null, 0);
       IRubyObject rubyObject = ruby.runNormally(scriptRootNode);

	if (rubyObject instanceof RubyNil) {
		String className = findClassName(scriptRootNode);
		rubyObject = ruby.evalScriptlet("\n" + className + ".new");
	}
	// still null?
	if (rubyObject instanceof RubyNil) {
		throw new IllegalStateException("Compilation of JRuby script returned RubyNil: " + rubyObject);
	}

	return Proxy.newProxyInstance(classLoader, interfaces, new RubyObjectInvocationHandler(rubyObject, ruby));
}
 

/**
 * This method facilitates conversion from Ruby objects to Pig objects. This is
 * a general class which detects the subclass and invokes the appropriate conversion
 * routine. It will fail on an unsupported datatype.
 *
 * @param  rbObject      a Ruby object to convert
 * @return               the Pig analogue of the Ruby object
 * @throws ExecException if rbObject is not of a known type that can be converted
 */
@SuppressWarnings("unchecked")
public static Object rubyToPig(IRubyObject rbObject) throws ExecException {
    if (rbObject == null || rbObject instanceof RubyNil) {
        return null;
    } else if (rbObject instanceof RubyArray) {
        return rubyToPig((RubyArray)rbObject);
    } else if (rbObject instanceof RubyHash) {
        return rubyToPig((RubyHash)rbObject);
    } else if (rbObject instanceof RubyString) {
        return rubyToPig((RubyString)rbObject);
    } else if (rbObject instanceof RubyBignum) {
        return rubyToPig((RubyBignum)rbObject);
    } else if (rbObject instanceof RubyFixnum) {
        return rubyToPig((RubyFixnum)rbObject);
    } else if (rbObject instanceof RubyFloat) {
        return rubyToPig((RubyFloat)rbObject);
    } else if (rbObject instanceof RubyInteger) {
        return rubyToPig((RubyInteger)rbObject);
    } else if (rbObject instanceof RubyDataBag) {
        return rubyToPig((RubyDataBag)rbObject);
    } else if (rbObject instanceof RubyDataByteArray) {
        return rubyToPig((RubyDataByteArray)rbObject);
    } else if (rbObject instanceof RubySchema) {
        return rubyToPig((RubySchema)rbObject);
    } else if (rbObject instanceof RubyBoolean) {
        return rubyToPig((RubyBoolean)rbObject);
    } else {
        throw new ExecException("Cannot cast into any pig supported type: " + rbObject.getClass().getName());
    }
}
 

@Override
public Row get(int index) {
    IRubyObject o = rubyArray.at(rubyArray.getRuntime().newFixnum(index));
    if (o == null || o instanceof RubyNil) {
        return null;
    }
    return new RowImpl(o);
}
 

public String getString(String propertyName, Object... args) {
    IRubyObject result = getRubyProperty(propertyName, args);

    if (result instanceof RubyNil) {
        return null;
    } else if (result instanceof RubySymbol) {
        return result.asJavaString();
    } else {
        return result.asJavaString();
    }
}
 

public String getSymbol(String propertyName, Object... args) {
    IRubyObject result = getRubyProperty(propertyName, args);

    if (result instanceof RubyNil) {
        return null;
    }
    return result.asJavaString();
}
 

public boolean getBoolean(String propertyName, Object... args) {
    IRubyObject result = getRubyProperty(propertyName, args);
    if (result instanceof RubyNil) {
        return false;
    } else {
        return result.isTrue();
    }
}
 

public int getInt(String propertyName, Object... args) {
    IRubyObject result = getRubyProperty(propertyName, args);
    if (result instanceof RubyNil) {
        return 0;
    } else {
        return (int) ((RubyNumeric) result).getLongValue();
    }
}
 

public <T> List<T> getList(String propertyName, Class<T> elementClass, Object... args) {
    IRubyObject result = getRubyProperty(propertyName, args);
    if (result instanceof RubyNil) {
        return null;
    } else {
        List<T> ret = new ArrayList<T>();
        RubyArray array = (RubyArray) result;
        for (int i = 0; i < array.size(); i++) {
            ret.add(RubyUtils.rubyToJava(runtime, array.at(RubyFixnum.newFixnum(runtime, i)), elementClass));
        }
        return ret;
    }
}
 

/**
 * A type specific conversion routine.
 *
 * @param  rbObject object to convert
 * @return          analogous Pig type
 */
public static Object rubyToPig(RubyNil rbObject) {
    return null;
}