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## java.awt
Class Component.FlipBufferStrategy

    java.lang.Object
      |
      +--java.awt.image.BufferStrategy
            |
            +--java.awt.Component.FlipBufferStrategy

Enclosing class:
  Component

protected class Component.FlipBufferStrategy
extends BufferStrategy

Inner class for flipping buffers on a component. That component must be a `Canvas` or `Window`.

Since:
  1.4
See Also:
  `Canvas`, `Window`, `BufferStrategy`

Field Summary
`protected BufferCapabilities` | `caps` The buffering capabilities
`protected Image` | `drawBuffer` The drawing buffer
`protected VolatileImage` | `drawVBuffer` The drawing buffer as a volatile image
`protected int` | `numBuffers` The number of buffers
`protected boolean` | `validatedContents` Whether or not the drawing buffer has been recently restored from a lost state.

Constructor Summary
`protected` | `Component.FlipBufferStrategy(int numBuffers, BufferCapabilities caps)` Creates a new flipping buffer strategy for this component.

Method Summary
`boolean` | `contentsLost()` Returns whether the drawing buffer was lost since the last call to `getDrawGraphics`.
`boolean` | `contentsRestored()` Returns whether the drawing buffer was recently restored from a lost state and reinitialized to the default background color (white).
`protected void` | `createBuffers(int numBuffers, BufferCapabilities caps)` Creates one or more complex, flipping buffers with the given capabilities.
`protected void` | `destroyBuffers()` Destroys the buffers created through this object
`protected void` | `flip(BufferCapabilities.FlipContents flipAction)` Flipping moves the contents of the back buffer to the front buffer, either by copying or by moving the video pointer.
`protected Image` | `getBackBuffer()`
`BufferCapabilities` | `getCapabilities()`
`Graphics` | `getDrawGraphics()`
`protected void` | `revalidate()` Restore the drawing buffer if it has been lost
`void` | `show()` Makes the next available buffer visible by either blitting or flipping.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### numBuffers

    protected int numBuffers

  The number of buffers

### caps

    protected BufferCapabilities caps

  The buffering capabilities

### drawBuffer

    protected Image drawBuffer

  The drawing buffer

### drawVBuffer

    protected VolatileImage drawVBuffer

  The drawing buffer as a volatile image

### validatedContents

    protected boolean validatedContents

  Whether or not the drawing buffer has been recently restored from a lost state.

Constructor Detail

### Component.FlipBufferStrategy

    protected Component.FlipBufferStrategy(int numBuffers,
                                           BufferCapabilities caps)
                                    throws AWTException

  Creates a new flipping buffer strategy for this component. The component must be a `Canvas` or `Window`.

Parameters:
  `numBuffers` - the number of buffers
  `caps` - the capabilities of the buffers
Throws:
  `AWTException` - if the capabilities supplied could not be supported or met
  `ClassCastException` - if the component is not a canvas or window.
See Also:
  `Canvas`, `Window`

Method Detail

### createBuffers

    protected void createBuffers(int numBuffers,
                                 BufferCapabilities caps)
                          throws AWTException

  Creates one or more complex, flipping buffers with the given capabilities.

  Parameters:
    `numBuffers` - number of buffers to create; must be greater than one
    `caps` - the capabilities of the buffers. `BufferCapabilities.isPageFlipping` must be `true`.
  Throws:
    `AWTException` - if the capabilities supplied could not be supported or met
    `IllegalStateException` - if the component has no peer
    `IllegalArgumentException` - if numBuffers is less than two, or if `BufferCapabilities.isPageFlipping` is not `true`.
  See Also:
    `java.awt.image.BufferCapabilities#isPageFlipping`

### getBackBuffer

    protected Image getBackBuffer()

  Throws:
    `IllegalStateException` - if the buffers have not yet been created

### flip

    protected void flip(BufferCapabilities.FlipContents flipAction)

  Flipping moves the contents of the back buffer to the front buffer, either by copying or by moving the video pointer.

  Parameters:
    `flipAction` - an integer value describing the flipping action for the contents of the back buffer. This should be one of the values of the `BufferCapabilities.FlipContents` property.
  Throws:
    `IllegalStateException` - if the buffers have not yet been created
  See Also:
    `java.awt.image.BufferCapabilities#FlipContents`

### destroyBuffers

    protected void destroyBuffers()

  Destroys the buffers created through this object

### getCapabilities

    public BufferCapabilities getCapabilities()

  Specified by:
    `getCapabilities` in class `BufferStrategy`
  Returns:
    the buffering capabilities of this strategy

### getDrawGraphics

    public Graphics getDrawGraphics()

  Specified by:
    `getDrawGraphics` in class `BufferStrategy`
  Returns:
    the graphics on the drawing buffer. This method may not be synchronized for performance reasons; use of this method by multiple threads should be handled at the application level. Disposal of the graphics object must be handled by the application.

### revalidate

    protected void revalidate()

  Restore the drawing buffer if it has been lost

### contentsLost

    public boolean contentsLost()

  Description copied from class: `BufferStrategy`
  Returns whether the drawing buffer was lost since the last call to `getDrawGraphics`. Since the buffers in a buffer strategy are usually type `VolatileImage`, they may become lost. For a discussion on lost buffers, see `VolatileImage`.

  Specified by:
    `contentsLost` in class `BufferStrategy`
  Returns:
    whether the drawing buffer was lost since the last call to `getDrawGraphics`
  See Also:
    `VolatileImage`

### contentsRestored

    public boolean contentsRestored()

  Description copied from class: `BufferStrategy`
  Returns whether the drawing buffer was recently restored from a lost state and reinitialized to the default background color (white). Since the buffers in a buffer strategy are usually type `VolatileImage`, they may become lost. If a surface has been recently restored from a lost state since the last call to `getDrawGraphics`, it may require repainting. For a discussion on lost buffers, see `VolatileImage`.

  Specified by:
    `contentsRestored` in class `BufferStrategy`
  Returns:
    whether the drawing buffer was recently restored from a lost state and reinitialized to the default background color (white)
  See Also:
    `VolatileImage`

### show

    public void show()

  Makes the next available buffer visible by either blitting or flipping.

  Specified by:
    `show` in class `BufferStrategy`

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