As of Spring 2.5, this class supports JRuby 0.9.9, 0.9.9 and 1.0.x.
* Note that there is no support for JRuby 1.1 at this point!
*
* @author Rob Harrop
* @author Juergen Hoeller
* @author Rick Evans
* @since 2.0
*/
public abstract class JRubyScriptUtils {
// Determine whether the old JRuby 0.9 parse method is available (incompatible with 1.0)
private final static Method oldParseMethod = ClassUtils.getMethodIfAvailable(
Ruby.class, "parse", new Class[] {String.class, String.class, DynamicScope.class});
/**
* Create a new JRuby-scripted object from the given script source,
* using the default {@link ClassLoader}.
* @param scriptSource the script source text
* @param interfaces the interfaces that the scripted Java object is to implement
* @return the scripted Java object
* @throws JumpException in case of JRuby parsing failure
* @see ClassUtils#getDefaultClassLoader()
*/
public static Object createJRubyObject(String scriptSource, Class[] interfaces) throws JumpException {
return createJRubyObject(scriptSource, interfaces, ClassUtils.getDefaultClassLoader());
}
/**
* 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 = (oldParseMethod != null ?
(Node) ReflectionUtils.invokeMethod(oldParseMethod, ruby, new Object[] {scriptSource, "", null}) :
ruby.parse(scriptSource, "", null, 0));
IRubyObject rubyObject = ruby.eval(scriptRootNode);
if (rubyObject instanceof RubyNil) {
String className = findClassName(scriptRootNode);
rubyObject = ruby.evalScript("\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));
}
/**
* Initializes an instance of the {@link org.jruby.Ruby} runtime.
*/
private static Ruby initializeRuntime() {
return JavaEmbedUtils.initialize(Collections.EMPTY_LIST);
}
/**
* Given the root {@link Node} in a JRuby AST will locate the name of the
* class defined by that AST.
* @throws IllegalArgumentException if no class is defined by the supplied AST
*/
private static String findClassName(Node rootNode) {
ClassNode classNode = findClassNode(rootNode);
if (classNode == null) {
throw new IllegalArgumentException("Unable to determine class name for root node '" + rootNode + "'");
}
Colon2Node node = (Colon2Node) classNode.getCPath();
return node.getName();
}
/**
* Find the first {@link ClassNode} under the supplied {@link Node}.
* @return the found ClassNode, or null
* if no {@link ClassNode} is found
*/
private static ClassNode findClassNode(Node node) {
if (node instanceof ClassNode) {
return (ClassNode) node;
}
List children = node.childNodes();
for (int i = 0; i < children.size(); i++) {
Node child = (Node) children.get(i);
if (child instanceof ClassNode) {
return (ClassNode) child;
} else if (child instanceof NewlineNode) {
NewlineNode nn = (NewlineNode) child;
Node found = findClassNode(nn.getNextNode());
if (found instanceof ClassNode) {
return (ClassNode) found;
}
}
}
for (int i = 0; i < children.size(); i++) {
Node child = (Node) children.get(i);
Node found = findClassNode(child);
if (found instanceof ClassNode) {
return (ClassNode) found;
}
}
return null;
}
/**
* InvocationHandler that invokes a JRuby script method.
*/
private static class RubyObjectInvocationHandler implements InvocationHandler {
private final IRubyObject rubyObject;
private final Ruby ruby;
public RubyObjectInvocationHandler(IRubyObject rubyObject, Ruby ruby) {
this.rubyObject = rubyObject;
this.ruby = ruby;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if (ReflectionUtils.isEqualsMethod(method)) {
return (isProxyForSameRubyObject(args[0]) ? Boolean.TRUE : Boolean.FALSE);
}
else if (ReflectionUtils.isHashCodeMethod(method)) {
return new Integer(this.rubyObject.hashCode());
}
else if (ReflectionUtils.isToStringMethod(method)) {
String toStringResult = this.rubyObject.toString();
if (!StringUtils.hasText(toStringResult)) {
toStringResult = ObjectUtils.identityToString(this.rubyObject);
}
return "JRuby object [" + toStringResult + "]";
}
try {
IRubyObject[] rubyArgs = convertToRuby(args);
IRubyObject rubyResult =
this.rubyObject.callMethod(this.ruby.getCurrentContext(), method.getName(), rubyArgs);
return convertFromRuby(rubyResult, method.getReturnType());
}
catch (RaiseException ex) {
throw new JRubyExecutionException(ex);
}
}
private boolean isProxyForSameRubyObject(Object other) {
if (!Proxy.isProxyClass(other.getClass())) {
return false;
}
InvocationHandler ih = Proxy.getInvocationHandler(other);
return (ih instanceof RubyObjectInvocationHandler &&
this.rubyObject.equals(((RubyObjectInvocationHandler) ih).rubyObject));
}
private IRubyObject[] convertToRuby(Object[] javaArgs) {
if (javaArgs == null || javaArgs.length == 0) {
return new IRubyObject[0];
}
IRubyObject[] rubyArgs = new IRubyObject[javaArgs.length];
for (int i = 0; i < javaArgs.length; ++i) {
rubyArgs[i] = JavaEmbedUtils.javaToRuby(this.ruby, javaArgs[i]);
}
return rubyArgs;
}
private Object convertFromRuby(IRubyObject rubyResult, Class returnType) {
Object result = JavaEmbedUtils.rubyToJava(this.ruby, rubyResult, returnType);
if (result instanceof RubyArray && returnType.isArray()) {
result = convertFromRubyArray(((RubyArray) result).toJavaArray(), returnType);
}
return result;
}
private Object convertFromRubyArray(IRubyObject[] rubyArray, Class returnType) {
Class targetType = returnType.getComponentType();
Object javaArray = Array.newInstance(targetType, rubyArray.length);
for (int i = 0; i < rubyArray.length; i++) {
IRubyObject rubyObject = rubyArray[i];
Array.set(javaArray, i, convertFromRuby(rubyObject, targetType));
}
return javaArray;
}
}
/**
* Exception thrown in response to a JRuby {@link RaiseException}
* being thrown from a JRuby method invocation.
*
Introduced because the RaiseException class does not
* have useful {@link Object#toString()}, {@link Throwable#getMessage()},
* and {@link Throwable#printStackTrace} implementations.
*/
public static class JRubyExecutionException extends NestedRuntimeException {
/**
* Create a new JRubyException,
* wrapping the given JRuby RaiseException.
* @param ex the cause (must not be null)
*/
public JRubyExecutionException(RaiseException ex) {
super(buildMessage(ex), ex);
}
private static String buildMessage(RaiseException ex) {
RubyException rubyEx = ex.getException();
return (rubyEx != null && rubyEx.message != null) ? rubyEx.message.toString() : "Unexpected JRuby error";
}
}
}