--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/javauis/eswt_qt/org.eclipse.swt/Eclipse_SWT_PI/qt/org/eclipse/swt/internal/qt/graphics/NativeCommandBuffer.java	Mon May 03 12:27:20 2010 +0300
@@ -0,0 +1,95 @@
+package org.eclipse.swt.internal.qt.graphics;
+
+/**
+ * Buffer provides a storage for GraphicsContext commands. If GraphicsContext is bound to
+ * Buffer all subsequental draw commands are recorded within the buffer and can be replayed 
+ * later by processing it with GraphicsContext.render()-method.
+ * 
+ * The main benefit of buffer is the possibility to render to it outside paint callbacks, 
+ * i.e. when the actual rendering target cannot be bound. Usage of buffer may also improve 
+ * performance.
+ * 
+ */
+public final class NativeCommandBuffer {
+
+	/**
+	 * Native peer handle
+	 */
+	int handle = 0;
+	
+	/**
+	 * State of native peer
+	 */
+	boolean disposed;
+	
+	/**
+	 * Constructor
+	 * @throws OutOfMemoryError If native buffer creation fails
+	 */
+	public NativeCommandBuffer() {
+		Utils.validateUiThread();
+		handle = OS.buffer_init();
+		if (handle == 0) {
+			throw new OutOfMemoryError("Native buffer creation failed");
+		}
+	}
+	
+	/**
+	 * Disposes this buffer and cleans all related native resources
+	 */
+	public void dispose() {
+		if (!disposed) {
+			OS.buffer_dispose(handle);
+			handle = 0;
+			disposed = true;
+		}
+	}
+
+    /**
+     * Gets the rectangle where draw operations have affected,
+     * i.e. the invalid rectangle.
+     *
+     * Values are stored in rect array as follows: 
+     * <ul>
+     * <li>rect[0] - the x coordinate of rect</li>
+     * <li>rect[1] - the y coordinate of rect
+     * <li>rect[2] - the width of rect
+     * <li>rect[3] - the height of rect
+     * </ul>
+     * 
+     * @param rect Integer array where the rect data is populated, size must be atleast 4
+     * @throws NullPointerException if rect is null
+     * @throws IllegalArgumentException if rect.length < 4
+     * @throws IllegalStateException if the buffer has already been disposed
+	 */
+	public void getInvalidRect(int[] rect) {
+		checkState();
+		if(rect == null) {
+			throw new NullPointerException("rect is null");
+		}
+		if(rect.length < 4) {
+			throw new IllegalArgumentException("rect array size is < 4");
+		}
+		OS.buffer_getInvalidRect(handle, rect);
+	}
+	
+    /**
+     * Gets the state of this Buffer, i.e. is it disposed or not. 
+     * 
+     * @return true if this instanace has been disposed, otherwise false
+     */
+	public boolean isDisposed() {
+		return disposed;
+	}
+	
+    /**
+     * private method for checking the state of this instance.
+     * @throws IllegalStateException If this instance is already disposed 
+     */
+    private void checkState() {
+    	Utils.validateUiThread();
+        if (disposed) {
+            throw new IllegalStateException("Buffer already disposed");
+        }
+    }
+}