beanshell.java

Linux下面最好用的程序、文本编辑工具之一。

		try
		{
			return _eval(view,namespace,command);
		}
		catch(Throwable e)
		{
			Log.log(Log.ERROR,BeanShell.class,e);

			handleException(view,null,e);
		}

		return null;
	} //}}}

	//{{{ _eval() method
	/**
	 * Evaluates the specified BeanShell expression. Unlike
	 * <code>eval()</code>, this method passes any exceptions to the caller.
	 *
	 * @param view The view. Within the script, references to
	 * <code>buffer</code>, <code>textArea</code> and <code>editPane</code>
	 * are determined with reference to this parameter.
	 * @param namespace The namespace
	 * @param command The expression
	 * @exception Exception instances are thrown when various BeanShell
	 * errors occur
	 * @since jEdit 3.2pre7
	 */
	public static Object _eval(View view, NameSpace namespace, String command)
		throws Exception
	{
		Interpreter interp = createInterpreter(namespace);

		try
		{
			setupDefaultVariables(namespace,view);
			if(Debug.BEANSHELL_DEBUG)
				Log.log(Log.DEBUG,BeanShell.class,command);
			return interp.eval(command);
		}
		catch(Exception e)
		{
			unwrapException(e);
			// never called
			return null;
		}
		finally
		{
			try
			{
				resetDefaultVariables(namespace);
			}
			catch(UtilEvalError e)
			{
				// do nothing
			}
		}
	} //}}}

	//{{{ cacheBlock() method
	/**
	 * Caches a block of code, returning a handle that can be passed to
	 * runCachedBlock().
	 * @param id An identifier. If null, a unique identifier is generated
	 * @param code The code
	 * @param namespace If true, the namespace will be set
	 * @exception Exception instances are thrown when various BeanShell errors
	 * occur
	 * @since jEdit 4.1pre1
	 */
	public static BshMethod cacheBlock(String id, String code, boolean namespace)
		throws Exception
	{
		String name = "__internal_" + id;

		// evaluate a method declaration
		if(namespace)
		{
			_eval(null,global,name + "(ns) {\nthis.callstack.set(0,ns);\n" + code + "\n}");
			return global.getMethod(name,new Class[] { NameSpace.class });
		}
		else
		{
			_eval(null,global,name + "() {\n" + code + "\n}");
			return global.getMethod(name,new Class[0]);
		}
	} //}}}

	//{{{ runCachedBlock() method
	/**
	 * Runs a cached block of code in the specified namespace. Faster than
	 * evaluating the block each time.
	 * @param method The method instance returned by cacheBlock()
	 * @param view The view
	 * @param namespace The namespace to run the code in
	 * @exception Exception instances are thrown when various BeanShell
	 * errors occur
	 * @since jEdit 4.1pre1
	 */
	public static Object runCachedBlock(BshMethod method, View view,
		NameSpace namespace) throws Exception
	{
		boolean useNamespace;
		if(namespace == null)
		{
			useNamespace = false;
			namespace = global;
		}
		else
			useNamespace = true;

		try
		{
			setupDefaultVariables(namespace,view);

			Object retVal = method.invoke(useNamespace
				? new Object[] { namespace }
				: NO_ARGS,
				interpForMethods,new CallStack());
			if(retVal instanceof Primitive)
			{
				if(retVal == Primitive.VOID)
					return null;
				else
					return ((Primitive)retVal).getValue();
			}
			else
				return retVal;
		}
		catch(Exception e)
		{
			unwrapException(e);
			// never called
			return null;
		}
		finally
		{
			resetDefaultVariables(namespace);
		}
	} //}}}

	//{{{ isScriptRunning() method
	/**
	 * Returns if a BeanShell script or macro is currently running.
	 * @since jEdit 2.7pre2
	 */
	public static boolean isScriptRunning()
	{
		return running;
	} //}}}

	//{{{ getNameSpace() method
	/**
	 * Returns the global namespace.
	 * @since jEdit 3.2pre5
	 */
	public static NameSpace getNameSpace()
	{
		return global;
	} //}}}

	//{{{ Deprecated functions

	//{{{ runScript() method
	/**
	 * @deprecated The <code>rethrowBshErrors</code> parameter is now
	 * obsolete; call <code>_runScript()</code> or <code>runScript()</code>
	 * instead.
	 */
	public static void runScript(View view, String path,
		boolean ownNamespace, boolean rethrowBshErrors)
	{
		runScript(view,path,null,ownNamespace);
	} //}}}

	//{{{ runScript() method
	/**
	 * @deprecated The <code>rethrowBshErrors</code> parameter is now
	 * obsolete; call <code>_runScript()</code> or <code>runScript()</code>
	 * instead.
	 */
	public static void runScript(View view, String path, Reader in,
		boolean ownNamespace, boolean rethrowBshErrors)
	{
		runScript(view,path,in,ownNamespace);
	} //}}}

	//{{{ eval() method
	/**
	 * @deprecated The <code>rethrowBshErrors</code> parameter is now
	 * obsolete; call <code>_eval()</code> or <code>eval()</code> instead.
	 */
	public static Object eval(View view, String command,
		boolean rethrowBshErrors)
	{
		return eval(view,global,command);
	} //}}}

	//{{{ eval() method
	/**
	 * @deprecated The <code>rethrowBshErrors</code> parameter is now
	 * obsolete; call <code>_eval()</code> or <code>eval()</code> instead.
	 */
	public static Object eval(View view, NameSpace namespace,
		String command, boolean rethrowBshErrors)
	{
		return eval(view,namespace,command);
	} //}}}

	//}}}

	//{{{ Package-private members

	//{{{ init() method
	static void init()
	{
		try
		{
			NameSpace.class.getMethod("addCommandPath",
				new Class[] { String.class, Class.class });
		}
		catch(Exception e)
		{
			Log.log(Log.ERROR,BeanShell.class,"You have BeanShell version " + Interpreter.VERSION + " in your CLASSPATH.");
			Log.log(Log.ERROR,BeanShell.class,"Please remove it from the CLASSPATH since jEdit can only run with the bundled BeanShell version " + REQUIRED_VERSION);
			System.exit(1);
		}

		classManager = new CustomClassManager();
		classManager.setClassLoader(new JARClassLoader());

		global = new NameSpace(classManager,
			"jEdit embedded BeanShell interpreter");
		global.importPackage("org.gjt.sp.jedit");
		global.importPackage("org.gjt.sp.jedit.browser");
		global.importPackage("org.gjt.sp.jedit.buffer");
		global.importPackage("org.gjt.sp.jedit.gui");
		global.importPackage("org.gjt.sp.jedit.help");
		global.importPackage("org.gjt.sp.jedit.io");
		global.importPackage("org.gjt.sp.jedit.menu");
		global.importPackage("org.gjt.sp.jedit.msg");
		global.importPackage("org.gjt.sp.jedit.options");
		global.importPackage("org.gjt.sp.jedit.pluginmgr");
		global.importPackage("org.gjt.sp.jedit.print");
		global.importPackage("org.gjt.sp.jedit.search");
		global.importPackage("org.gjt.sp.jedit.syntax");
		global.importPackage("org.gjt.sp.jedit.textarea");
		global.importPackage("org.gjt.sp.util");

		interpForMethods = createInterpreter(global);
	} //}}}

	//{{{ resetClassManager() method
	/**
	 * Causes BeanShell internal structures to drop references to cached
	 * Class instances.
	 */
	static void resetClassManager()
	{
		classManager.reset();
	} //}}}

	//}}}

	//{{{ Private members

	//{{{ Static variables
	private static final Object[] NO_ARGS = new Object[0];
	private static CustomClassManager classManager;
	private static Interpreter interpForMethods;
	private static NameSpace global;
	private static boolean running;
	//}}}

	//{{{ setupDefaultVariables() method
	private static void setupDefaultVariables(NameSpace namespace, View view)
		throws UtilEvalError
	{
		if(view != null)
		{
			EditPane editPane = view.getEditPane();
			namespace.setVariable("view",view);
			namespace.setVariable("editPane",editPane);
			namespace.setVariable("buffer",editPane.getBuffer());
			namespace.setVariable("textArea",editPane.getTextArea());
			namespace.setVariable("wm",view.getDockableWindowManager());
		}
	} //}}}

	//{{{ resetDefaultVariables() method
	private static void resetDefaultVariables(NameSpace namespace)
		throws UtilEvalError
	{
		namespace.setVariable("view",null);
		namespace.setVariable("editPane",null);
		namespace.setVariable("buffer",null);
		namespace.setVariable("textArea",null);
		namespace.setVariable("wm",null);
	} //}}}

	//{{{ unwrapException() method
	/**
	 * This extracts an exception from a 'wrapping' exception, as BeanShell
	 * sometimes throws. This gives the user a more accurate error traceback
	 */
	private static void unwrapException(Exception e) throws Exception
	{
		if(e instanceof TargetError)
		{
			Throwable t = ((TargetError)e).getTarget();
			if(t instanceof Exception)
				throw (Exception)t;
			else if(t instanceof Error)
				throw (Error)t;
		}

		if(e instanceof InvocationTargetException)
		{
			Throwable t = ((InvocationTargetException)e).getTargetException();
			if(t instanceof Exception)
				throw (Exception)t;
			else if(t instanceof Error)
				throw (Error)t;
		}

		throw e;
	} //}}}

	//{{{ handleException() method
	private static void handleException(View view, String path, Throwable t)
	{
		if(t instanceof IOException)
		{
			VFSManager.error(view,path,"ioerror.read-error",
				new String[] { t.toString() });
		}
		else
			new BeanShellErrorDialog(view,t);
	} //}}}

	//{{{ createInterpreter() method
	private static Interpreter createInterpreter(NameSpace nameSpace)
	{
		return new Interpreter(null,System.out,System.err,false,nameSpace);
	} //}}}

	//}}}

	//{{{ CustomClassManager class
	static class CustomClassManager extends BshClassManager
	{
		private LinkedList listeners = new LinkedList();
		private ReferenceQueue refQueue = new ReferenceQueue();

		// copy and paste from bsh/classpath/ClassManagerImpl.java...
		public synchronized void addListener( Listener l )
		{
			listeners.add( new WeakReference( l, refQueue) );

			// clean up old listeners
			Reference deadref;
			while ( (deadref = refQueue.poll()) != null )
			{
				boolean ok = listeners.remove( deadref );
				if ( ok )
				{
					//System.err.println("cleaned up weak ref: "+deadref);
				}
				else
				{
					if ( Interpreter.DEBUG ) Interpreter.debug(
						"tried to remove non-existent weak ref: "+deadref);
				}
			}
		}

		public void removeListener( Listener l )
		{
			throw new Error("unimplemented");
		}

		public void reset()
		{
			classLoaderChanged();
		}

		protected synchronized void classLoaderChanged()
		{
			// clear the static caches in BshClassManager
			clearCaches();

			for (Iterator iter = listeners.iterator();
				iter.hasNext(); )
			{
				WeakReference wr = (WeakReference)
					iter.next();
				Listener l = (Listener)wr.get();
				if ( l == null )  // garbage collected
					iter.remove();
				else
					l.classLoaderChanged();
			}
		}
	} //}}}
}