org.springframework.scripting.jruby.JRubyScriptUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2007 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.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Collections;
import java.util.List;
import org.jruby.IRuby;
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.javasupport.JavaEmbedUtils;
import org.jruby.javasupport.JavaUtil;
import org.jruby.runtime.builtin.IRubyObject;
import org.springframework.aop.support.AopUtils;
import org.springframework.scripting.ScriptCompilationException;
import org.springframework.util.ClassUtils;
/**
* Utility methods for handling JRuby-scripted objects.
*
* Note: As of Spring 2.0.2, this class requires JRuby 0.9.2 or higher.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
*/
public abstract class JRubyScriptUtils {
/**
* 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 supposed to implement
* @return the scripted Java object
* @throws JumpException in case of JRuby parsing failure
*/
public static Object createJRubyObject(String scriptSource, Class[] interfaces) throws JumpException {
IRuby ruby = initializeRuntime();
Node scriptRootNode = ruby.parse(scriptSource, "", null);
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 ScriptCompilationException("Compilation of JRuby script returned '" + rubyObject + "'");
}
return Proxy.newProxyInstance(ClassUtils.getDefaultClassLoader(),
interfaces, new RubyObjectInvocationHandler(rubyObject, ruby));
}
/**
* Initializes an instance of the {@link IRuby} runtime.
*/
private static IRuby 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();
}
/**
* Finds the first {@link ClassNode} under the supplied {@link Node}. Returns
* '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 IRuby ruby;
public RubyObjectInvocationHandler(IRubyObject rubyObject, IRuby ruby) {
this.rubyObject = rubyObject;
this.ruby = ruby;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if (AopUtils.isToStringMethod(method)) {
return "JRuby object [" + this.rubyObject + "]";
}
IRubyObject[] rubyArgs = convertToRuby(args);
IRubyObject result = this.rubyObject.callMethod(this.ruby.getCurrentContext(), method.getName(), rubyArgs);
return JavaUtil.convertRubyToJava(result);
}
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;
}
}
}