Robot (Java SE 17 & JDK 17)
Description: declaration: module: java.desktop, package: java.awt, class: Robot
Keywords: java.awt.Robot class

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

  - ### 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`

- ## 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(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.

    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:
      - `SecurityManager.checkPermission(java.security.Permission)`
      - `AWTPermission`

  - ### 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:
      - `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.

    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.