JMeter example source code file (BeanShellInterpreter.java)

This example JMeter source code file (BeanShellInterpreter.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

beanshell, can't, class, class, classnotfoundexception, classnotfoundexception, io, jmeterexception, jmeterexception, logger, method, non-nls-1, object, object, reflection, string

The JMeter BeanShellInterpreter.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.io.File;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.apache.jorphan.logging.LoggingManager;
import org.apache.jorphan.util.JMeterError;
import org.apache.jorphan.util.JMeterException;
import org.apache.log.Logger;

/**
 * BeanShell setup function - encapsulates all the access to the BeanShell
 * Interpreter in a single class.
 *
 * The class uses dynamic class loading to access BeanShell, which means that
 * all the source files can be built without needing access to the bsh jar.
 *
 * If the beanshell jar is not present at run-time, an error will be logged
 *
 */

public class BeanShellInterpreter {
    private static final Logger log = LoggingManager.getLoggerForClass();

    private static final Method bshGet;

    private static final Method bshSet;

    private static final Method bshEval;

    private static final Method bshSource;

    private static final Class<?> bshClass;

    private static final String BSH_INTERPRETER = "bsh.Interpreter"; //$NON-NLS-1$

    static {
        // Temporary copies, so can set the final ones
        Method get = null, eval = null, set = null, source = null;
        Class<?> clazz = null;
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        try {
            clazz = loader.loadClass(BSH_INTERPRETER);
            Class<String> string = String.class;
            Class<Object> object = Object.class;

            get = clazz.getMethod("get", //$NON-NLS-1$
                    new Class[] { string });
            eval = clazz.getMethod("eval", //$NON-NLS-1$
                    new Class[] { string });
            set = clazz.getMethod("set", //$NON-NLS-1$
                    new Class[] { string, object });
            source = clazz.getMethod("source", //$NON-NLS-1$
                    new Class[] { string });
        } catch (ClassNotFoundException e) {
            log.error("Beanshell Interpreter not found");
        } catch (SecurityException e) {
            log.error("Beanshell Interpreter not found", e);
        } catch (NoSuchMethodException e) {
            log.error("Beanshell Interpreter not found", e);
        } finally {
            bshEval = eval;
            bshGet = get;
            bshSet = set;
            bshSource = source;
            bshClass = clazz;
        }
    }

    // This class is not serialised
    private Object bshInstance = null; // The interpreter instance for this class

    private final String initFile; // Script file to initialize the Interpreter with

    private final Logger logger; // Logger to use during initialization and script run

    public BeanShellInterpreter() throws ClassNotFoundException {
        initFile = null;
        logger = null;
        init();
    }

    /**
     *
     * @param init initialisation file
     * @param _log logger to pass to interpreter
     */
    public BeanShellInterpreter(String init, Logger _log)  throws ClassNotFoundException {
        initFile = init;
        logger = _log;
        init();
    }

    // Called from ctor, so must be private (or final, but it does not seem useful elsewhere)
    private void init() throws ClassNotFoundException {
        if (bshClass == null) {
            throw new ClassNotFoundException(BSH_INTERPRETER);
        }
        try {
            bshInstance = bshClass.newInstance();
        } catch (InstantiationException e) {
            log.error("Can't instantiate BeanShell", e);
            throw new ClassNotFoundException("Can't instantiate BeanShell", e);
        } catch (IllegalAccessException e) {
            log.error("Can't instantiate BeanShell", e);
            throw new ClassNotFoundException("Can't instantiate BeanShell", e);
        }
         if (logger != null) {// Do this before starting the script
            try {
                set("log", logger);//$NON-NLS-1$
            } catch (JMeterException e) {
                log.warn("Can't set logger variable", e);
            }
        }
        if (initFile != null && initFile.length() > 0) {
            String fileToUse=initFile;
            // Check file so we can distinguish file error from script error
            File in = new File(fileToUse);
            if (!in.exists()){// Cannot find the file locally, so try the bin directory
                fileToUse=JMeterUtils.getJMeterHome()
                        +File.separator+"bin" // $NON-NLS-1$
                        +File.separator+initFile;
                in = new File(fileToUse);
                if (!in.exists()) {
                    log.warn("Cannot find init file: "+initFile);
                }
            }
            if (!in.canRead()) {
                log.warn("Cannot read init file: "+fileToUse);
            }
            try {
                source(fileToUse);
            } catch (JMeterException e) {
                log.warn("Cannot source init file: "+fileToUse,e);
            }
        }
    }

    /**
     * Resets the BeanShell interpreter.
     *
     * @throws ClassNotFoundException if interpreter cannot be instantiated
     */
    public void reset() throws ClassNotFoundException {
       init();
    }

    private Object bshInvoke(Method m, Object[] o, boolean shouldLog) throws JMeterException {
        Object r = null;
        final String errorString = "Error invoking bsh method: ";
        try {
            r = m.invoke(bshInstance, o);
        } catch (IllegalArgumentException e) { // Programming error
            final String message = errorString + m.getName();
            log.error(message);
            throw new JMeterError(message, e);
        } catch (IllegalAccessException e) { // Also programming error
            final String message = errorString + m.getName();
            log.error(message);
            throw new JMeterError(message, e);
        } catch (InvocationTargetException e) { // Can occur at run-time
            // could be caused by the bsh Exceptions:
            // EvalError, ParseException or TargetError
            String message = errorString + m.getName();
            Throwable cause = e.getCause();
            if (cause != null) {
                message += "\t" + cause.getLocalizedMessage();
            }

            if (shouldLog) {
                log.error(message);
            }
            throw new JMeterException(message, e);
        }
        return r;
    }

    public Object eval(String s) throws JMeterException {
        return bshInvoke(bshEval, new Object[] { s }, true);
    }

    public Object evalNoLog(String s) throws JMeterException {
        return bshInvoke(bshEval, new Object[] { s }, false);
    }

    public Object set(String s, Object o) throws JMeterException {
        return bshInvoke(bshSet, new Object[] { s, o }, true);
    }

    public Object set(String s, boolean b) throws JMeterException {
        return bshInvoke(bshSet, new Object[] { s, Boolean.valueOf(b) }, true);
    }

    public Object source(String s) throws JMeterException {
        return bshInvoke(bshSource, new Object[] { s }, true);
    }

    public Object get(String s) throws JMeterException {
        return bshInvoke(bshGet, new Object[] { s }, true);
    }

    // For use by Unit Tests
    public static boolean isInterpreterPresent(){
        return bshClass != null;
    }
}