Scriptpad Sample

• Introduction

Scriptpad is a notepad like editor to open/edit/save and run script (JavaScript) files. This sample demonstrates the use of javax.script (JSR-223) API and JavaScript engine that is bundled with JDK 6.

Scriptpad sample demonstrates how to use Javascript to use Java classes and objects to perform various tasks such as to modify, customize Swing GUI or to connect to a running application and monitor it using JMX (Java Management Extensions) API.

• How to run Scriptpad?

Scriptpad can be run with the following command:

java -jar ./build/scriptpad.jar

(be sure to use the correct version of java). You can open/edit/save scripts using menu items under "File" menu. To run currently edited script, you can use "Tools->Run" menu.

For example, you may enter

alert("hello, world");

in the editor and run the same with "Tools->Run" menu. You will see an alert box with the message "hello, world".

In addition to being a simple script editor/runner, scriptpad can be used to connect to a JMX MBean server ("Tools->JMX Connect" menu). User can specify JMX hostname and port. After connecting, user can use "monitoring and management" script functions defined in "mm.js" (see below).

• Scriptpad Sources

com.sun.demo.scriptpad.Main class is the entry point of this sample. This class creates ScriptEngine and evaluates few JavaScript "files" -- which are stored as resources (please refer to src/resources/*.js). Actual code for the scriptpad's main functionality lives in these JavaScript files.

1. conc.js -- simple concurrency utilities for JavaScript

2. gui.js -- simple GUI utilities for JavaScript

3. mm.js -- Monitoring and Management utilities for JavaScript

4. scriptpad.js -- This creates main "notepad"-like GUI for open/edit/save and run script files

5. Main.js -- This script file can be used under "jrunscript" tool. jrunscript is an experimental tool shipped with JDK (under $JDK_HOME/bin directory). The scriptpad application can be run by the following commands:

   cd ./src/resources $JDK_HOME/bin/jrunscript -f Main.js -f -

• Extending Scriptpad:

It is possible to extend scriptpad using scripts. There is a global object called "application". This object has 2 fields and a method.

Fields of the application object:

    frame  -> JFrame of the scriptpad
    editor -> editor pane of the scriptpad

Method of the application object:

    addTool -> adds a menu item under "Tools" menu

Example script to add "Tools->Hello" menu item:

    application.addTool("Hello", 
        function() { alert("hello, world"); });

After running the above script, you can click Tools->Hello menu item and you'll see an alert box.

Scriptpad customization may also be done by defining a file named "scriptpad.js" under your home directory,. If this file is found, scriptpad loads this file just after initializating everything. In your initialization file, you can additional script functions by "load" function.

• Script Samples:

On clicking the menu items under "Examples" menu, scriptpad shows built-in examples in the editor. Also, there are few script samples under the ./src/scripts directory.

• Monitoring and Management with Scriptpad:

(1) Start the application with the JMX agent - here's an example of how the Java2D demo is started

  java -Dcom.sun.management.jmxremote.port=1090          \
       -Dcom.sun.management.jmxremote.ssl=false          \
       -Dcom.sun.management.jmxremote.authenticate=false \
       -jar $JDK_HOME/demo/jfc/Font2DTest/Font2DTest.jar

(2) Start scriptpad and click on "Tools->JMX Connect" menu. In the prompt, enter "localhost:1090" to connect to the above program.

After connecting to a MBeanServer (using "Tools->JMX Connect"), you can run any script that uses functions defined in "mm.js". For example, it is possible to load and run management scripts that are part of JConsole script shell plugin under the directory:

$JDK_HOME/demo/scripting/jconsole-plugin/src/scripts