/*
* Copyright 2002-2014 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.scripting.jruby;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Collections;
import java.util.List;
import org.jruby.Ruby;
import org.jruby.RubyArray;
import org.jruby.RubyNil;
import org.jruby.ast.ClassNode;
import org.jruby.ast.Colon2Node;
import org.jruby.ast.NewlineNode;
import org.jruby.ast.Node;
import org.jruby.exceptions.JumpException;
import org.jruby.exceptions.RaiseException;
import org.jruby.javasupport.JavaEmbedUtils;
import org.jruby.runtime.builtin.IRubyObject;
import org.springframework.core.NestedRuntimeException;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;
/**
* Utility methods for handling JRuby-scripted objects.
*
* <p>Note: Spring 4.0 supports JRuby 1.5 and higher.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @author Rick Evans
* @since 2.0
*/
public abstract class JRubyScriptUtils {
/**
* 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 = 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));
}
/**
* 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 corresponding {@code ClassNode}, or {@code null} if none found
*/
private static ClassNode findClassNode(Node node) {
if (node == null) {
return null;
}
if (node instanceof ClassNode) {
return (ClassNode) node;
}
List<Node> children = node.childNodes();
for (Node child : children) {
if (child instanceof ClassNode) {
return (ClassNode) child;
}
else if (child instanceof NewlineNode) {
NewlineNode nn = (NewlineNode) child;
ClassNode found = findClassNode(nn.getNextNode());
if (found != null) {
return found;
}
}
}
for (Node child : children) {
ClassNode found = findClassNode(child);
if (found != null) {
return 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;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if (ReflectionUtils.isEqualsMethod(method)) {
return (isProxyForSameRubyObject(args[0]));
}
else if (ReflectionUtils.isHashCodeMethod(method)) {
return 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.
*/
@SuppressWarnings("serial")
public static class JRubyExecutionException extends NestedRuntimeException {
/**
* Create a new {@code JRubyException},
* wrapping the given JRuby {@code RaiseException}.
* @param ex the cause (must not be {@code null})
*/
public JRubyExecutionException(RaiseException ex) {
super(ex.getMessage(), ex);
}
}
}