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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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/*
* This source code is provided to illustrate the usage of a given feature
* or technique and has been deliberately simplified. Additional steps
* required for a production-quality application, such as security checks,
* input validation and proper error handling, might not be present in
* this sample code.
*/
package com.sun.demo.scripting.jconsole;
import com.sun.tools.jconsole.*;
import java.io.*;
import java.util.concurrent.CountDownLatch;
import javax.script.*;
import javax.swing.*;
import java.util.*;
/**
* This is script console plugin. This class uses javax.script API to create
* interactive read-eval-print script shell within the jconsole GUI.
*/
public class ScriptJConsolePlugin extends JConsolePlugin
implements ScriptShellPanel.CommandProcessor {
// Panel for our tab
private volatile ScriptShellPanel window;
// Tabs that we add to jconsole GUI
private Map<String, JPanel> tabs;
// Script engine that evaluates scripts
private volatile ScriptEngine engine;
// script engine initialization occurs in background.
// This latch is used to coorrdinate engine init and eval.
private CountDownLatch engineReady = new CountDownLatch(1);
// File extension used for scripts of chosen language.
// For eg. ".js" for JavaScript, ".bsh" for BeanShell.
private String extension;
// Prompt to print in the read-eval-print loop. This is
// derived from the script file extension.
private volatile String prompt;
/**
* Constructor to create this plugin
*/
public ScriptJConsolePlugin() {
}
@Override public Map<String, JPanel> getTabs() {
// create ScriptEngine
createScriptEngine();
// create panel for tab
window = new ScriptShellPanel(this);
// add tab to tabs map
tabs = new HashMap<String, JPanel>();
tabs.put("Script Shell", window);
new Thread(new Runnable() {
@Override
public void run() {
// initialize the script engine
initScriptEngine();
engineReady.countDown();
}
}).start();
return tabs;
}
@Override public SwingWorker<?,?> newSwingWorker() {
return null;
}
@Override public void dispose() {
window.dispose();
}
@Override
public String getPrompt() {
return prompt;
}
@Override
public String executeCommand(String cmd) {
String res;
try {
engineReady.await();
Object tmp = engine.eval(cmd);
res = (tmp == null)? null : tmp.toString();
} catch (InterruptedException ie) {
res = ie.getMessage();
} catch (ScriptException se) {
res = se.getMessage();
}
return res;
}
//-- Internals only below this point
private void createScriptEngine() {
ScriptEngineManager manager = new ScriptEngineManager();
String language = getScriptLanguage();
engine = manager.getEngineByName(language);
if (engine == null) {
throw new RuntimeException("cannot load " + language + " engine");
}
extension = engine.getFactory().getExtensions().get(0);
prompt = extension + ">";
engine.setBindings(createBindings(), ScriptContext.ENGINE_SCOPE);
}
// Name of the System property used to select scripting language
private static final String LANGUAGE_KEY = "com.sun.demo.jconsole.console.language";
private String getScriptLanguage() {
// check whether explicit System property is set
String lang = System.getProperty(LANGUAGE_KEY);
if (lang == null) {
// default is JavaScript
lang = "JavaScript";
}
return lang;
}
// create Bindings that is backed by a synchronized HashMap
private Bindings createBindings() {
Map<String, Object> map =
Collections.synchronizedMap(new HashMap<String, Object>());
return new SimpleBindings(map);
}
// create and initialize script engine
private void initScriptEngine() {
// set pre-defined global variables
setGlobals();
// load pre-defined initialization file
loadInitFile();
// load current user's initialization file
loadUserInitFile();
}
// set pre-defined global variables for script
private void setGlobals() {
engine.put("engine", engine);
engine.put("window", window);
engine.put("plugin", this);
}
// load initial script file (jconsole.<extension>)
private void loadInitFile() {
String oldFilename = (String) engine.get(ScriptEngine.FILENAME);
engine.put(ScriptEngine.FILENAME, "<built-in jconsole." + extension + ">");
try {
Class<? extends ScriptJConsolePlugin> myClass = this.getClass();
InputStream stream = myClass.getResourceAsStream("/resources/jconsole." +
extension);
if (stream != null) {
engine.eval(new InputStreamReader(new BufferedInputStream(stream)));
}
} catch (Exception exp) {
exp.printStackTrace();
// FIXME: What else I can do here??
} finally {
engine.put(ScriptEngine.FILENAME, oldFilename);
}
}
// load user's initial script file (~/jconsole.<extension>)
private void loadUserInitFile() {
String oldFilename = (String) engine.get(ScriptEngine.FILENAME);
String home = System.getProperty("user.home");
if (home == null) {
// no user.home?? should not happen??
return;
}
String fileName = home + File.separator + "jconsole." + extension;
if (! (new File(fileName).exists())) {
// user does not have ~/jconsole.<extension>
return;
}
engine.put(ScriptEngine.FILENAME, fileName);
try {
engine.eval(new FileReader(fileName));
} catch (Exception exp) {
exp.printStackTrace();
// FIXME: What else I can do here??
} finally {
engine.put(ScriptEngine.FILENAME, oldFilename);
}
}
}