InputEvent (Java Platform SE 8 )
Keywords: java.awt.event.InputEvent class
Date: 2016-12-09

java.awt.event

## Class InputEvent

- java.lang.Object
- - java.util.EventObject
  - - java.awt.AWTEvent
    - - java.awt.event.ComponentEvent
      - - java.awt.event.InputEvent

- All Implemented Interfaces:
    Serializable
  Direct Known Subclasses:
    KeyEvent, MouseEvent

      public abstract class InputEvent
      extends ComponentEvent

  The root event class for all component-level input events. Input events are delivered to listeners before they are processed normally by the source where they originated. This allows listeners and component subclasses to "consume" the event so that the source will not process them in their default manner. For example, consuming mousePressed events on a Button component will prevent the Button from being activated.
  Since:
    1.1
  See Also:
    `KeyEvent`, `KeyAdapter`, `MouseEvent`, `MouseAdapter`, `MouseMotionAdapter`, Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `ALT_DOWN_MASK` The Alt key extended modifier constant.
    `static int` | `ALT_GRAPH_DOWN_MASK` The AltGraph key extended modifier constant.
    `static int` | `ALT_GRAPH_MASK` The AltGraph key modifier constant.
    `static int` | `ALT_MASK` The Alt key modifier constant.
    `static int` | `BUTTON1_DOWN_MASK` The Mouse Button1 extended modifier constant.
    `static int` | `BUTTON1_MASK` The Mouse Button1 modifier constant.
    `static int` | `BUTTON2_DOWN_MASK` The Mouse Button2 extended modifier constant.
    `static int` | `BUTTON2_MASK` The Mouse Button2 modifier constant.
    `static int` | `BUTTON3_DOWN_MASK` The Mouse Button3 extended modifier constant.
    `static int` | `BUTTON3_MASK` The Mouse Button3 modifier constant.
    `static int` | `CTRL_DOWN_MASK` The Control key extended modifier constant.
    `static int` | `CTRL_MASK` The Control key modifier constant.
    `static int` | `META_DOWN_MASK` The Meta key extended modifier constant.
    `static int` | `META_MASK` The Meta key modifier constant.
    `static int` | `SHIFT_DOWN_MASK` The Shift key extended modifier constant.
    `static int` | `SHIFT_MASK` The Shift key modifier constant.

    - ### Fields inherited from class java.awt.event.ComponentEvent

      `COMPONENT_FIRST, COMPONENT_HIDDEN, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN`

    - ### Fields inherited from class java.awt.AWTEvent

      `ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, HIERARCHY_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, WINDOW_STATE_EVENT_MASK`

    - ### Fields inherited from class java.util.EventObject

      `source`

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `consume()` Consumes this event so that it will not be processed in the default manner by the source which originated it.
    `static int` | `getMaskForButton(int button)` A method to obtain a mask for any existing mouse button.
    `int` | `getModifiers()` Returns the modifier mask for this event.
    `int` | `getModifiersEx()` Returns the extended modifier mask for this event.
    `static String` | `getModifiersExText(int modifiers)` Returns a String describing the extended modifier keys and mouse buttons, such as "Shift", "Button1", or "Ctrl+Shift".
    `long` | `getWhen()` Returns the difference in milliseconds between the timestamp of when this event occurred and midnight, January 1, 1970 UTC.
    `boolean` | `isAltDown()` Returns whether or not the Alt modifier is down on this event.
    `boolean` | `isAltGraphDown()` Returns whether or not the AltGraph modifier is down on this event.
    `boolean` | `isConsumed()` Returns whether or not this event has been consumed.
    `boolean` | `isControlDown()` Returns whether or not the Control modifier is down on this event.
    `boolean` | `isMetaDown()` Returns whether or not the Meta modifier is down on this event.
    `boolean` | `isShiftDown()` Returns whether or not the Shift modifier is down on this event.

    - ### Methods inherited from class java.awt.event.ComponentEvent

      `getComponent, paramString`

    - ### Methods inherited from class java.awt.AWTEvent

      `getID, setSource, toString`

    - ### Methods inherited from class java.util.EventObject

      `getSource`

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### SHIFT_MASK

          public static final int SHIFT_MASK

      The Shift key modifier constant. It is recommended that SHIFT_DOWN_MASK be used instead.
      See Also:
        Constant Field Values

    - #### CTRL_MASK

          public static final int CTRL_MASK

      The Control key modifier constant. It is recommended that CTRL_DOWN_MASK be used instead.
      See Also:
        Constant Field Values

    - #### META_MASK

          public static final int META_MASK

      The Meta key modifier constant. It is recommended that META_DOWN_MASK be used instead.
      See Also:
        Constant Field Values

    - #### ALT_MASK

          public static final int ALT_MASK

      The Alt key modifier constant. It is recommended that ALT_DOWN_MASK be used instead.
      See Also:
        Constant Field Values

    - #### ALT_GRAPH_MASK

          public static final int ALT_GRAPH_MASK

      The AltGraph key modifier constant.
      See Also:
        Constant Field Values

    - #### BUTTON1_MASK

          public static final int BUTTON1_MASK

      The Mouse Button1 modifier constant. It is recommended that BUTTON1_DOWN_MASK be used instead.
      See Also:
        Constant Field Values

    - #### BUTTON2_MASK

          public static final int BUTTON2_MASK

      The Mouse Button2 modifier constant. It is recommended that BUTTON2_DOWN_MASK be used instead. Note that BUTTON2_MASK has the same value as ALT_MASK.
      See Also:
        Constant Field Values

    - #### BUTTON3_MASK

          public static final int BUTTON3_MASK

      The Mouse Button3 modifier constant. It is recommended that BUTTON3_DOWN_MASK be used instead. Note that BUTTON3_MASK has the same value as META_MASK.
      See Also:
        Constant Field Values

    - #### SHIFT_DOWN_MASK

          public static final int SHIFT_DOWN_MASK

      The Shift key extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### CTRL_DOWN_MASK

          public static final int CTRL_DOWN_MASK

      The Control key extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### META_DOWN_MASK

          public static final int META_DOWN_MASK

      The Meta key extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### ALT_DOWN_MASK

          public static final int ALT_DOWN_MASK

      The Alt key extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### BUTTON1_DOWN_MASK

          public static final int BUTTON1_DOWN_MASK

      The Mouse Button1 extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### BUTTON2_DOWN_MASK

          public static final int BUTTON2_DOWN_MASK

      The Mouse Button2 extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### BUTTON3_DOWN_MASK

          public static final int BUTTON3_DOWN_MASK

      The Mouse Button3 extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

    - #### ALT_GRAPH_DOWN_MASK

          public static final int ALT_GRAPH_DOWN_MASK

      The AltGraph key extended modifier constant.
      Since:
        1.4
      See Also:
        Constant Field Values

  - ### Method Detail

    - #### getMaskForButton

          public static int getMaskForButton(int button)

      A method to obtain a mask for any existing mouse button. The returned mask may be used for different purposes. Following are some of them:
      - `mousePress(buttons)` and `mouseRelease(buttons)`
      - as a `modifiers` parameter when creating a new `MouseEvent` instance
      - to check `modifiersEx` of existing `MouseEvent`
      Parameters:
        `button` - is a number to represent a button starting from 1. For example,

             int button = InputEvent.getMaskForButton(1);

        will have the same meaning as

             int button = InputEvent.getMaskForButton(MouseEvent.BUTTON1);

        because `MouseEvent.BUTTON1` equals to 1. If a mouse has three enabled buttons(see `MouseInfo.getNumberOfButtons()`) then the values from the left column passed into the method will return corresponding values from the right column:

                button    returned mask
                BUTTON1  BUTTON1_DOWN_MASK
                BUTTON2  BUTTON2_DOWN_MASK
                BUTTON3  BUTTON3_DOWN_MASK

        If a mouse has more than three enabled buttons then more values are admissible (4, 5, etc.). There is no assigned constants for these extended buttons. The button masks for the extra buttons returned by this method have no assigned names like the first three button masks.

        This method has the following implementation restriction. It returns masks for a limited number of buttons only. The maximum number is implementation dependent and may vary. This limit is defined by the relevant number of buttons that may hypothetically exist on the mouse but it is greater than the `MouseInfo.getNumberOfButtons()`.

      Throws:
        `IllegalArgumentException` - if `button` is less than zero or greater than the number of button masks reserved for buttons
      Since:
        7.0
      See Also:
        `MouseInfo.getNumberOfButtons()`, `Toolkit.areExtraMouseButtonsEnabled()`, `getModifiers()`, `MouseEvent.getModifiersEx()`

    - #### isShiftDown

          public boolean isShiftDown()

      Returns whether or not the Shift modifier is down on this event.

    - #### isControlDown

          public boolean isControlDown()

      Returns whether or not the Control modifier is down on this event.

    - #### isMetaDown

          public boolean isMetaDown()

      Returns whether or not the Meta modifier is down on this event.

    - #### isAltDown

          public boolean isAltDown()

      Returns whether or not the Alt modifier is down on this event.

    - #### isAltGraphDown

          public boolean isAltGraphDown()

      Returns whether or not the AltGraph modifier is down on this event.

    - #### getWhen

          public long getWhen()

      Returns the difference in milliseconds between the timestamp of when this event occurred and midnight, January 1, 1970 UTC.

    - #### getModifiers

          public int getModifiers()

      Returns the modifier mask for this event.

    - #### getModifiersEx

          public int getModifiersEx()

      Returns the extended modifier mask for this event.

      Extended modifiers are the modifiers that ends with the _DOWN_MASK suffix, such as ALT_DOWN_MASK, BUTTON1_DOWN_MASK, and others.

      Extended modifiers represent the state of all modal keys, such as ALT, CTRL, META, and the mouse buttons just after the event occurred.

      For example, if the user presses button 1 followed by button 2, and then releases them in the same order, the following sequence of events is generated:

              MOUSE_PRESSED:  BUTTON1_DOWN_MASK
              MOUSE_PRESSED:  BUTTON1_DOWN_MASK | BUTTON2_DOWN_MASK
              MOUSE_RELEASED: BUTTON2_DOWN_MASK
              MOUSE_CLICKED:  BUTTON2_DOWN_MASK
              MOUSE_RELEASED:
              MOUSE_CLICKED:

      It is not recommended to compare the return value of this method using `==` because new modifiers can be added in the future. For example, the appropriate way to check that SHIFT and BUTTON1 are down, but CTRL is up is demonstrated by the following code:

              int onmask = SHIFT_DOWN_MASK | BUTTON1_DOWN_MASK;
              int offmask = CTRL_DOWN_MASK;
              if ((event.getModifiersEx() & (onmask | offmask)) == onmask) {
                  ...
              }

      The above code will work even if new modifiers are added.
      Since:
        1.4

    - #### consume

          public void consume()

      Consumes this event so that it will not be processed in the default manner by the source which originated it.
      Overrides:
        `consume` in class `AWTEvent`

    - #### isConsumed

          public boolean isConsumed()

      Returns whether or not this event has been consumed.
      Overrides:
        `isConsumed` in class `AWTEvent`
      See Also:
        `consume()`

    - #### getModifiersExText

          public static String getModifiersExText(int modifiers)

      Returns a String describing the extended modifier keys and mouse buttons, such as "Shift", "Button1", or "Ctrl+Shift". These strings can be localized by changing the `awt.properties` file.

      Note that passing negative parameter is incorrect, and will cause the returning an unspecified string. Zero parameter means that no modifiers were passed and will cause the returning an empty string.

      Parameters:
        `modifiers` - a modifier mask describing the extended modifier keys and mouse buttons for the event
      Returns:
        a text description of the combination of extended modifier keys and mouse buttons that were held down during the event.
      Since:
        1.4

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