JMeter example source code file (BSFJavaScriptEngine.java)

This example JMeter source code file (BSFJavaScriptEngine.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - JMeter tags/keywords

bsfexception, bsfexception, context, error, javascriptexception, object, object, override, scriptable, stackoverflowerror, string, string, throwable, throwable, util

The JMeter BSFJavaScriptEngine.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.jmeter.util;

import java.util.Iterator;
import java.util.Vector;

import org.apache.bsf.BSFDeclaredBean;
import org.apache.bsf.BSFException;
import org.apache.bsf.BSFManager;
import org.apache.bsf.util.BSFEngineImpl;
import org.apache.bsf.util.BSFFunctions;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.EvaluatorException;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.ImporterTopLevel;
import org.mozilla.javascript.JavaScriptException;
import org.mozilla.javascript.NativeJavaObject;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.WrappedException;
import org.mozilla.javascript.Wrapper;

/**
 * This is the interface to Netscape's Rhino (JavaScript) from the
 * Bean Scripting Framework.
 * <p>
 * The original version of this code was first written by Adam Peller
 * for use in LotusXSL. Sanjiva took his code and adapted it for BSF.
 *
 * Modified for JMeter to fix bug BSF-22.
 */
public class BSFJavaScriptEngine extends BSFEngineImpl {
    /**
     * The global script object, where all embedded functions are defined,
     * as well as the standard ECMA "core" objects.
     */
    private Scriptable global;

    /**
     * Return an object from an extension.
     * @param object Object on which to make the call (ignored).
     * @param method The name of the method to call.
     * @param args an array of arguments to be
     * passed to the extension, which may be either
     * Vectors of Nodes, or Strings.
     */
    public Object call(Object object, String method, Object[] args)
        throws BSFException {

        Object retval = null;
        Context cx;

        try {
            cx = Context.enter();

            // REMIND: convert arg list Vectors here?

            Object fun = global.get(method, global);
            // NOTE: Source and line arguments are nonsense in a call().
            //       Any way to make these arguments *sensible?
            if (fun == Scriptable.NOT_FOUND)
                throw new EvaluatorException("function " + method +
                                             " not found.", "none", 0);

            cx.setOptimizationLevel(-1);
            cx.setGeneratingDebug(false);
            cx.setGeneratingSource(false);
            cx.setOptimizationLevel(0);
            cx.setDebugger(null, null);

            retval =
                ((Function) fun).call(cx, global, global, args);

//                ScriptRuntime.call(cx, fun, global, args, global);

            if (retval instanceof Wrapper)
                retval = ((Wrapper) retval).unwrap();
        }
        catch (Throwable t) {
            handleError(t);
        }
        finally {
            Context.exit();
        }
        return retval;
    }

    @Override
    public void declareBean(BSFDeclaredBean bean) throws BSFException {
        if ((bean.bean instanceof Number) ||
            (bean.bean == null) ||
            (bean.bean instanceof String) ||
            (bean.bean instanceof Boolean)) {
            global.put(bean.name, global, bean.bean);
        }
        else {
            // Must wrap non-scriptable objects before presenting to Rhino
            Scriptable wrapped = Context.toObject(bean.bean, global);
            global.put(bean.name, global, wrapped);
        }
    }

    /**
     * This is used by an application to evaluate a string containing
     * some expression.
     */
    public Object eval(String source, int lineNo, int columnNo, Object oscript)
        throws BSFException {

        String scriptText = oscript.toString();
        Object retval = null;
        Context cx;

        try {
            cx = Context.enter();

            cx.setOptimizationLevel(-1);
            cx.setGeneratingDebug(false);
            cx.setGeneratingSource(false);
            cx.setOptimizationLevel(0);
            cx.setDebugger(null, null);

            retval = cx.evaluateString(global, scriptText,
                                       source, lineNo,
                                       null);

            if (retval instanceof NativeJavaObject)
                retval = ((NativeJavaObject) retval).unwrap();

        }
        catch (Throwable t) { // includes JavaScriptException, rethrows Errors
            handleError(t);
        }
        finally {
            Context.exit();
        }
        return retval;
    }

    private void handleError(Throwable t) throws BSFException {
        if (t instanceof WrappedException)
            t = ((WrappedException) t).getWrappedException();

        String message = null;
        Throwable target = t;

        if (t instanceof JavaScriptException) {
            message = t.getLocalizedMessage();

            // Is it an exception wrapped in a JavaScriptException?
            Object value = ((JavaScriptException) t).getValue();
            if (value instanceof Throwable) {
                // likely a wrapped exception from a LiveConnect call.
                // Display its stack trace as a diagnostic
                target = (Throwable) value;
            }
        }
        else if (t instanceof EvaluatorException ||
                 t instanceof SecurityException) {
            message = t.getLocalizedMessage();
        }
        else if (t instanceof RuntimeException) {
            message = "Internal Error: " + t.toString();
        }
        else if (t instanceof StackOverflowError) {
            message = "Stack Overflow";
        }

        if (message == null)
            message = t.toString();

        if (t instanceof Error && !(t instanceof StackOverflowError)) {
            // Re-throw Errors because we're supposed to let the JVM see it
            // Don't re-throw StackOverflows, because we know we've
            // corrected the situation by aborting the loop and
            // a long stacktrace would end up on the user's console
            throw (Error) t;
        }
        else {
            throw new BSFException(BSFException.REASON_OTHER_ERROR,
                                   "JavaScript Error: " + message,
                                   target);
        }
    }

    /**
     * Initialize the engine.
     * Put the manager into the context-manager
     * map hashtable too.
     */
    @Override
    public void initialize(BSFManager mgr, String lang,
            @SuppressWarnings("rawtypes") // superclass does not support types
            Vector declaredBeans)
        throws BSFException {

        super.initialize(mgr, lang, declaredBeans);

        // Initialize context and global scope object
        try {
            Context cx = Context.enter();
            global = new ImporterTopLevel(cx);
            Scriptable bsf = Context.toObject(new BSFFunctions(mgr, this), global);
            global.put("bsf", global, bsf);

            for(
                @SuppressWarnings("unchecked")
                Iterator<BSFDeclaredBean> it = declaredBeans.iterator();
                it.hasNext();) {
                declareBean(it.next());
            }
        }
        catch (Throwable t) {

        }
        finally {
            Context.exit();
        }
    }

    @Override
    public void undeclareBean(BSFDeclaredBean bean) throws BSFException {
        global.delete(bean.name);
    }
}