Class Robot

public class Robot
extends Object

This class is used to generate native system input events for the purposes of test automation, self-running demos, and other applications where control of the mouse and keyboard is needed. The primary purpose of Robot is to facilitate automated testing of Java platform implementations.

Using the class to generate input events differs from posting events to the AWT event queue or AWT components in that the events are generated in the platform's native input queue. For example, Robot.mouseMove will actually move the mouse cursor instead of just generating mouse move events.

Note that some platforms require special privileges or extensions to access low-level input control. If the current platform configuration does not allow input control, an AWTException will be thrown when trying to construct Robot objects. For example, X-Window systems will throw the exception if the XTEST 2.2 standard extension is not supported (or not enabled) by the X server.

Applications that use Robot for purposes other than self-testing should handle these error conditions gracefully.

Since:
1.3

Constructors

Constructor Description
Robot()

Constructs a Robot object in the coordinate system of the primary screen.
Robot​(GraphicsDevice screen)

Creates a Robot for the given screen device.

Methods

Modifier and Type Method Description
MultiResolutionImage createMultiResolutionScreenCapture​(Rectangle screenRect)

Creates an image containing pixels read from the screen.
BufferedImage createScreenCapture​(Rectangle screenRect)

Creates an image containing pixels read from the screen.
void delay​(int ms)

Sleeps for the specified time.
int getAutoDelay()

Returns the number of milliseconds this Robot sleeps after generating an event.
Color getPixelColor​(int x, int y)

Returns the color of a pixel at the given screen coordinates.
boolean isAutoWaitForIdle()

Returns whether this Robot automatically invokes waitForIdle after generating an event.
void keyPress​(int keycode)

Presses a given key.
void keyRelease​(int keycode)

Releases a given key.
void mouseMove​(int x, int y)

Moves mouse pointer to given screen coordinates.
void mousePress​(int buttons)

Presses one or more mouse buttons.
void mouseRelease​(int buttons)

Releases one or more mouse buttons.
void mouseWheel​(int wheelAmt)

Rotates the scroll wheel on wheel-equipped mice.
void setAutoDelay​(int ms)

Sets the number of milliseconds this Robot sleeps after generating an event.
void setAutoWaitForIdle​(boolean isOn)

Sets whether this Robot automatically invokes waitForIdle after generating an event.
String toString()

Returns a string representation of this Robot.
void waitForIdle()

Waits until all events currently on the event queue have been processed.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructors

Robot

public Robot()
      throws AWTException

Constructs a Robot object in the coordinate system of the primary screen.

Throws:
AWTException - if the platform configuration does not allow low-level input control. This exception is always thrown when GraphicsEnvironment.isHeadless() returns true
SecurityException - if createRobot permission is not granted
See Also:
GraphicsEnvironment.isHeadless(), SecurityManager.checkPermission(java.security.Permission), AWTPermission

Robot

public Robot(GraphicsDevice screen)
      throws AWTException

Creates a Robot for the given screen device. Coordinates passed to Robot method calls like mouseMove, getPixelColor and createScreenCapture will be interpreted as being in the same coordinate system as the specified screen. Note that depending on the platform configuration, multiple screens may either:

  • share the same coordinate system to form a combined virtual screen
  • use different coordinate systems to act as independent screens

If screen devices are reconfigured such that the coordinate system is affected, the behavior of existing Robot objects is undefined.

Parameters:
screen - A screen GraphicsDevice indicating the coordinate system the Robot will operate in.
Throws:
AWTException - if the platform configuration does not allow low-level input control. This exception is always thrown when GraphicsEnvironment.isHeadless() returns true.
IllegalArgumentException - if screen is not a screen GraphicsDevice.
SecurityException - if createRobot permission is not granted
See Also:
GraphicsEnvironment.isHeadless(), GraphicsDevice, SecurityManager.checkPermission(java.security.Permission), AWTPermission

Methods

mouseMove

public void mouseMove(int x,
                      int y)

Moves mouse pointer to given screen coordinates.

Parameters:
x - X position
y - Y position

mousePress

public void mousePress(int buttons)

Presses one or more mouse buttons. The mouse buttons should be released using the mouseRelease(int) method.

Parameters:
buttons - the Button mask; a combination of one or more mouse button masks.

It is allowed to use only a combination of valid values as a buttons parameter. A valid combination consists of InputEvent.BUTTON1_DOWN_MASK, InputEvent.BUTTON2_DOWN_MASK, InputEvent.BUTTON3_DOWN_MASK and values returned by the InputEvent.getMaskForButton(button) method. The valid combination also depends on a Toolkit.areExtraMouseButtonsEnabled() value as follows:

  • If support for extended mouse buttons is disabled by Java then it is allowed to use only the following standard button masks: InputEvent.BUTTON1_DOWN_MASK, InputEvent.BUTTON2_DOWN_MASK, InputEvent.BUTTON3_DOWN_MASK.
  • If support for extended mouse buttons is enabled by Java then it is allowed to use the standard button masks and masks for existing extended mouse buttons, if the mouse has more then three buttons. In that way, it is allowed to use the button masks corresponding to the buttons in the range from 1 to MouseInfo.getNumberOfButtons().
    It is recommended to use the InputEvent.getMaskForButton(button) method to obtain the mask for any mouse button by its number.

The following standard button masks are also accepted:

  • InputEvent.BUTTON1_MASK
  • InputEvent.BUTTON2_MASK
  • InputEvent.BUTTON3_MASK
However, it is recommended to use InputEvent.BUTTON1_DOWN_MASK, InputEvent.BUTTON2_DOWN_MASK, InputEvent.BUTTON3_DOWN_MASK instead. Either extended _DOWN_MASK or old _MASK values should be used, but both those models should not be mixed.
Throws:
IllegalArgumentException - if the buttons mask contains the mask for extra mouse button and support for extended mouse buttons is disabled by Java
IllegalArgumentException - if the buttons mask contains the mask for extra mouse button that does not exist on the mouse and support for extended mouse buttons is enabled by Java
See Also:
mouseRelease(int), InputEvent.getMaskForButton(int), Toolkit.areExtraMouseButtonsEnabled(), MouseInfo.getNumberOfButtons(), MouseEvent

mouseRelease

public void mouseRelease(int buttons)

Releases one or more mouse buttons.

Parameters:
buttons - the Button mask; a combination of one or more mouse button masks.

It is allowed to use only a combination of valid values as a buttons parameter. A valid combination consists of InputEvent.BUTTON1_DOWN_MASK, InputEvent.BUTTON2_DOWN_MASK, InputEvent.BUTTON3_DOWN_MASK and values returned by the InputEvent.getMaskForButton(button) method. The valid combination also depends on a Toolkit.areExtraMouseButtonsEnabled() value as follows:

  • If the support for extended mouse buttons is disabled by Java then it is allowed to use only the following standard button masks: InputEvent.BUTTON1_DOWN_MASK, InputEvent.BUTTON2_DOWN_MASK, InputEvent.BUTTON3_DOWN_MASK.
  • If the support for extended mouse buttons is enabled by Java then it is allowed to use the standard button masks and masks for existing extended mouse buttons, if the mouse has more then three buttons. In that way, it is allowed to use the button masks corresponding to the buttons in the range from 1 to MouseInfo.getNumberOfButtons().
    It is recommended to use the InputEvent.getMaskForButton(button) method to obtain the mask for any mouse button by its number.

The following standard button masks are also accepted:

  • InputEvent.BUTTON1_MASK
  • InputEvent.BUTTON2_MASK
  • InputEvent.BUTTON3_MASK
However, it is recommended to use InputEvent.BUTTON1_DOWN_MASK, InputEvent.BUTTON2_DOWN_MASK, InputEvent.BUTTON3_DOWN_MASK instead. Either extended _DOWN_MASK or old _MASK values should be used, but both those models should not be mixed.
Throws:
IllegalArgumentException - if the buttons mask contains the mask for extra mouse button and support for extended mouse buttons is disabled by Java
IllegalArgumentException - if the buttons mask contains the mask for extra mouse button that does not exist on the mouse and support for extended mouse buttons is enabled by Java
See Also:
mousePress(int), InputEvent.getMaskForButton(int), Toolkit.areExtraMouseButtonsEnabled(), MouseInfo.getNumberOfButtons(), MouseEvent

mouseWheel

public void mouseWheel(int wheelAmt)

Rotates the scroll wheel on wheel-equipped mice.

Parameters:
wheelAmt - number of "notches" to move the mouse wheel Negative values indicate movement up/away from the user, positive values indicate movement down/towards the user.
Since:
1.4

keyPress

public void keyPress(int keycode)

Presses a given key. The key should be released using the keyRelease method.

Key codes that have more than one physical key associated with them (e.g. KeyEvent.VK_SHIFT could mean either the left or right shift key) will map to the left key.

Parameters:
keycode - Key to press (e.g. KeyEvent.VK_A)
Throws:
IllegalArgumentException - if keycode is not a valid key
See Also:
keyRelease(int), KeyEvent

keyRelease

public void keyRelease(int keycode)

Releases a given key.

Key codes that have more than one physical key associated with them (e.g. KeyEvent.VK_SHIFT could mean either the left or right shift key) will map to the left key.

Parameters:
keycode - Key to release (e.g. KeyEvent.VK_A)
Throws:
IllegalArgumentException - if keycode is not a valid key
See Also:
keyPress(int), KeyEvent

getPixelColor

public Color getPixelColor(int x,
                           int y)

Returns the color of a pixel at the given screen coordinates.

Parameters:
x - X position of pixel
y - Y position of pixel
Returns:
Color of the pixel

createScreenCapture

public BufferedImage createScreenCapture(Rectangle screenRect)

Creates an image containing pixels read from the screen. This image does not include the mouse cursor.

Parameters:
screenRect - Rect to capture in screen coordinates
Returns:
The captured image
Throws:
IllegalArgumentException - if screenRect width and height are not greater than zero
SecurityException - if readDisplayPixels permission is not granted
See Also:
SecurityManager.checkPermission(java.security.Permission), AWTPermission

createMultiResolutionScreenCapture

public MultiResolutionImage createMultiResolutionScreenCapture(Rectangle screenRect)

Creates an image containing pixels read from the screen. This image does not include the mouse cursor. This method can be used in case there is a scaling transform from user space to screen (device) space. Typically this means that the display is a high resolution screen, although strictly it means any case in which there is such a transform. Returns a MultiResolutionImage.

For a non-scaled display, the MultiResolutionImage will have one image variant:

  • Base Image with user specified size.

For a high resolution display where there is a scaling transform, the MultiResolutionImage will have two image variants:

  • Base Image with user specified size. This is scaled from the screen.
  • Native device resolution image with device size pixels.

Example: 

Image nativeResImage;
      MultiResolutionImage mrImage = robot.createMultiResolutionScreenCapture(frame.getBounds());
      List<Image> resolutionVariants = mrImage.getResolutionVariants();
      if (resolutionVariants.size() > 1) {
          nativeResImage = resolutionVariants.get(1);
      } else {
          nativeResImage = resolutionVariants.get(0);
      }
Parameters:
screenRect - Rect to capture in screen coordinates
Returns:
The captured image
Throws:
IllegalArgumentException - if screenRect width and height are not greater than zero
SecurityException - if readDisplayPixels permission is not granted
Since:
9
See Also:
SecurityManager.checkPermission(java.security.Permission), AWTPermission

isAutoWaitForIdle

public boolean isAutoWaitForIdle()

Returns whether this Robot automatically invokes waitForIdle after generating an event.

Returns:
Whether waitForIdle is automatically called

setAutoWaitForIdle

public void setAutoWaitForIdle(boolean isOn)

Sets whether this Robot automatically invokes waitForIdle after generating an event.

Parameters:
isOn - Whether waitForIdle is automatically invoked

getAutoDelay

public int getAutoDelay()

Returns the number of milliseconds this Robot sleeps after generating an event.

Returns:
the delay duration in milliseconds

setAutoDelay

public void setAutoDelay(int ms)

Sets the number of milliseconds this Robot sleeps after generating an event.

Parameters:
ms - the delay duration in milliseconds
Throws:
IllegalArgumentException - If ms is not between 0 and 60,000 milliseconds inclusive

delay

public void delay(int ms)

Sleeps for the specified time. To catch any InterruptedExceptions that occur, Thread.sleep() may be used instead.

Parameters:
ms - time to sleep in milliseconds
Throws:
IllegalArgumentException - if ms is not between 0 and 60,000 milliseconds inclusive
See Also:
Thread.sleep(long)

waitForIdle

public void waitForIdle()

Waits until all events currently on the event queue have been processed.

Throws:
IllegalThreadStateException - if called on the AWT event dispatching thread

toString

public String toString()

Returns a string representation of this Robot.

Overrides:
toString in class Object
Returns:
the string representation.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/Robot.html