Module java.desktop
Package java.awt

Class Robot

java.lang.Object
java.awt.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.

Platforms and desktop environments may impose restrictions or limitations on the access required to implement all functionality in the Robot class. For example:

  • preventing access to the contents of any part of a desktop or Window on the desktop that is not owned by the running application.
  • treating window decorations as non-owned content.
  • ignoring or limiting specific requests to manipulate windows.
  • ignoring or limiting specific requests for Robot generated (synthesized) events related to keyboard and mouse etc.
  • requiring specific or global permissions to any access to window contents, even application owned content,or to perform even limited synthesizing of events.
The Robot API specification requires that approvals for these be granted for full operation. If they are not granted, the API will be degraded as discussed here. Relevant specific API methods may document more specific limitations and requirements. Depending on the policies of the desktop environment, the approvals mentioned above may:
  • be required every time
  • or persistent for the lifetime of an application,
  • or persistent across multiple user desktop sessions
  • be fine-grained permissions
  • be associated with a specific binary application, or a class of binary applications.
When such approvals need to given interactively, it may impede the normal operation of the application until approved, and if approval is denied or not possible, or cannot be made persistent then it will degrade the functionality of this class and in turn any part of the operation of the application which is dependent on it.
Since:
1.3

  • Constructor Summary

    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.

  • Method Summary

    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

  • Constructor Details

  • Method Details

    • mouseMove

      public void mouseMove(int x, int y)
      Moves mouse pointer to given screen coordinates.

      The mouse pointer may not visually move on some platforms, while the subsequent mousePress and mouseRelease can be delivered to the correct location

      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

      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:

    • 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

      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:

    • getPixelColor

      public Color getPixelColor(int x, int y)
      Returns the color of a pixel at the given screen coordinates.

      If the desktop environment requires that permissions be granted to capture screen content, and the required permissions are not granted, then a SecurityException may be thrown, or the content of the returned Color is undefined.

      API Note:
      It is recommended to avoid calling this method on the AWT Event Dispatch Thread since screen capture may be a lengthy operation, particularly if acquiring permissions is needed and involves user interaction.
      Parameters:
      x - X position of pixel
      y - Y position of pixel
      Returns:
      Color of the pixel
      Throws:
      SecurityException - if readDisplayPixels permission is not granted, or access to the screen is denied by the desktop environment

    • createScreenCapture

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

      If the desktop environment requires that permissions be granted to capture screen content, and the required permissions are not granted, then a SecurityException may be thrown, or the contents of the returned BufferedImage are undefined.

      API Note:
      It is recommended to avoid calling this method on the AWT Event Dispatch Thread since screen capture may be a lengthy operation, particularly if acquiring permissions is needed and involves user interaction.
      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, or access to the screen is denied by the desktop environment
      See Also:

    • createMultiResolutionScreenCapture

      public MultiResolutionImage createMultiResolutionScreenCapture(Rectangle screenRect)
      Creates an image containing pixels read from the screen. 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, or access to the screen is denied by the desktop environment
      Since:
      9
      See Also:

    • 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.

      If the invoking thread is interrupted while waiting, then it will return immediately with the interrupt status set. If the interrupted status is already set, this method returns immediately with the interrupt status set.

      Parameters:
      ms - time to sleep in milliseconds
      Throws:
      IllegalArgumentException - if ms is not between 0 and 60,000 milliseconds inclusive

    • 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.