Module java.desktop
Package java.awt.image

# Class DataBuffer

java.lang.Object
java.awt.image.DataBuffer

Direct Known Subclasses:
  `DataBufferByte`, `DataBufferDouble`, `DataBufferFloat`, `DataBufferInt`, `DataBufferShort`, `DataBufferUShort`

public abstract class DataBuffer extends Object
This class exists to wrap one or more data arrays. Each data array in the DataBuffer is referred to as a bank. Accessor methods for getting and setting elements of the DataBuffer's banks exist with and without a bank specifier. The methods without a bank specifier use the default 0th bank. The DataBuffer can optionally take an offset per bank, so that data in an existing array can be used even if the interesting data doesn't start at array location zero. Getting or setting the 0th element of a bank, uses the (0+offset)th element of the array. The size field specifies how much of the data array is available for use. Size + offset for a given bank should never be greater than the length of the associated data array. The data type of a data buffer indicates the type of the data array(s) and may also indicate additional semantics, e.g. storing unsigned 8-bit data in elements of a byte array. The data type may be TYPE_UNDEFINED or one of the types defined below. Other types may be added in the future. Generally, an object of class DataBuffer will be cast down to one of its data type specific subclasses to access data type specific methods for improved performance. Currently, the Java 2D(tm) API image classes use TYPE_BYTE, TYPE_USHORT, TYPE_INT, TYPE_SHORT, TYPE_FLOAT, and TYPE_DOUBLE DataBuffers to store image data.

See Also:
  - `Raster`
  - `SampleModel`

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected int`
  `banks`
  The number of banks in this DataBuffer.
  `protected int`
  `dataType`
  The data type of this DataBuffer.
  `protected int`
  `offset`
  Offset into default (first) bank from which to get the first element.
  `protected int[]`
  `offsets`
  Offsets into all banks.
  `protected int`
  `size`
  Usable size of all banks.
  `static final int`
  `TYPE_BYTE`
  Tag for unsigned byte data.
  `static final int`
  `TYPE_DOUBLE`
  Tag for double data.
  `static final int`
  `TYPE_FLOAT`
  Tag for float data.
  `static final int`
  `TYPE_INT`
  Tag for int data.
  `static final int`
  `TYPE_SHORT`
  Tag for signed short data.
  `static final int`
  `TYPE_UNDEFINED`
  Tag for undefined data.
  `static final int`
  `TYPE_USHORT`
  Tag for unsigned short data.

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `DataBuffer(int dataType, int size)`
  Constructs a DataBuffer containing one bank of the specified data type and size.
  `protected`
  `DataBuffer(int dataType, int size, int numBanks)`
  Constructs a DataBuffer containing the specified number of banks.
  `protected`
  `DataBuffer(int dataType, int size, int numBanks, int offset)`
  Constructs a DataBuffer that contains the specified number of banks.
  `protected`
  `DataBuffer(int dataType, int size, int numBanks, int[] offsets)`
  Constructs a DataBuffer which contains the specified number of banks.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `getDataType()`
  Returns the data type of this DataBuffer.
  `static int`
  `getDataTypeSize(int type)`
  Returns the size (in bits) of the data type, given a datatype tag.
  `int`
  `getElem(int i)`
  Returns the requested data array element from the first (default) bank as an integer.
  `abstract int`
  `getElem(int bank, int i)`
  Returns the requested data array element from the specified bank as an integer.
  `double`
  `getElemDouble(int i)`
  Returns the requested data array element from the first (default) bank as a double.
  `double`
  `getElemDouble(int bank, int i)`
  Returns the requested data array element from the specified bank as a double.
  `float`
  `getElemFloat(int i)`
  Returns the requested data array element from the first (default) bank as a float.
  `float`
  `getElemFloat(int bank, int i)`
  Returns the requested data array element from the specified bank as a float.
  `int`
  `getNumBanks()`
  Returns the number of banks in this DataBuffer.
  `int`
  `getOffset()`
  Returns the offset of the default bank in array elements.
  `int[]`
  `getOffsets()`
  Returns the offsets (in array elements) of all the banks.
  `int`
  `getSize()`
  Returns the size (in array elements) of all banks.
  `void`
  `setElem(int i, int val)`
  Sets the requested data array element in the first (default) bank from the given integer.
  `abstract void`
  `setElem(int bank, int i, int val)`
  Sets the requested data array element in the specified bank from the given integer.
  `void`
  `setElemDouble(int i, double val)`
  Sets the requested data array element in the first (default) bank from the given double.
  `void`
  `setElemDouble(int bank, int i, double val)`
  Sets the requested data array element in the specified bank from the given double.
  `void`
  `setElemFloat(int i, float val)`
  Sets the requested data array element in the first (default) bank from the given float.
  `void`
  `setElemFloat(int bank, int i, float val)`
  Sets the requested data array element in the specified bank from the given float.

  ### Methods declared in class java.lang.Object

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

- ## Field Details

  - ### TYPE_BYTE

    @Native public static final int TYPE_BYTE
    Tag for unsigned byte data.
    See Also:
      - Constant Field Values

  - ### TYPE_USHORT

    @Native public static final int TYPE_USHORT
    Tag for unsigned short data.
    See Also:
      - Constant Field Values

  - ### TYPE_SHORT

    @Native public static final int TYPE_SHORT
    Tag for signed short data.
    See Also:
      - Constant Field Values

  - ### TYPE_INT

    @Native public static final int TYPE_INT
    Tag for int data.
    See Also:
      - Constant Field Values

  - ### TYPE_FLOAT

    @Native public static final int TYPE_FLOAT
    Tag for float data.
    See Also:
      - Constant Field Values

  - ### TYPE_DOUBLE

    @Native public static final int TYPE_DOUBLE
    Tag for double data.
    See Also:
      - Constant Field Values

  - ### TYPE_UNDEFINED

    @Native public static final int TYPE_UNDEFINED
    Tag for undefined data.
    See Also:
      - Constant Field Values

  - ### dataType

    protected int dataType
    The data type of this DataBuffer.

  - ### banks

    protected int banks
    The number of banks in this DataBuffer.

  - ### offset

    protected int offset
    Offset into default (first) bank from which to get the first element.

  - ### size

    protected int size
    Usable size of all banks.

  - ### offsets

    protected int[] offsets
    Offsets into all banks.

- ## Constructor Details

  - ### DataBuffer

    protected DataBuffer(int dataType, int size)
    Constructs a DataBuffer containing one bank of the specified data type and size.
    Parameters:
      `dataType` - the data type of this `DataBuffer`
      `size` - the size of the banks

  - ### DataBuffer

    protected DataBuffer(int dataType, int size, int numBanks)
    Constructs a DataBuffer containing the specified number of banks. Each bank has the specified size and an offset of 0.
    Parameters:
      `dataType` - the data type of this `DataBuffer`
      `size` - the size of the banks
      `numBanks` - the number of banks in this `DataBuffer`

  - ### DataBuffer

    protected DataBuffer(int dataType, int size, int numBanks, int offset)
    Constructs a DataBuffer that contains the specified number of banks. Each bank has the specified datatype, size and offset.
    Parameters:
      `dataType` - the data type of this `DataBuffer`
      `size` - the size of the banks
      `numBanks` - the number of banks in this `DataBuffer`
      `offset` - the offset for each bank

  - ### DataBuffer

    protected DataBuffer(int dataType, int size, int numBanks, int[] offsets)
    Constructs a DataBuffer which contains the specified number of banks. Each bank has the specified datatype and size. The offset for each bank is specified by its respective entry in the offsets array.
    Parameters:
      `dataType` - the data type of this `DataBuffer`
      `size` - the size of the banks
      `numBanks` - the number of banks in this `DataBuffer`
      `offsets` - an array containing an offset for each bank.
    Throws:
      `ArrayIndexOutOfBoundsException` - if `numBanks` does not equal the length of `offsets`

- ## Method Details

  - ### getDataTypeSize

    public static int getDataTypeSize(int type)
    Returns the size (in bits) of the data type, given a datatype tag.
    Parameters:
      `type` - the value of one of the defined datatype tags
    Returns:
      the size of the data type
    Throws:
      `IllegalArgumentException` - if `type` is less than zero or greater than `TYPE_DOUBLE`

  - ### getDataType

    public int getDataType()
    Returns the data type of this DataBuffer.
    Returns:
      the data type of this `DataBuffer`.

  - ### getSize

    public int getSize()
    Returns the size (in array elements) of all banks.
    Returns:
      the size of all banks.

  - ### getOffset

    public int getOffset()
    Returns the offset of the default bank in array elements.
    Returns:
      the offset of the default bank.

  - ### getOffsets

    public int[] getOffsets()
    Returns the offsets (in array elements) of all the banks.
    Returns:
      the offsets of all banks.

  - ### getNumBanks

    public int getNumBanks()
    Returns the number of banks in this DataBuffer.
    Returns:
      the number of banks.

  - ### getElem

    public int getElem(int i)
    Returns the requested data array element from the first (default) bank as an integer.
    Parameters:
      `i` - the index of the requested data array element
    Returns:
      the data array element at the specified index.
    See Also:
      - `setElem(int, int)`
      - `setElem(int, int, int)`

  - ### getElem

    public abstract int getElem(int bank, int i)
    Returns the requested data array element from the specified bank as an integer.
    Parameters:
      `bank` - the specified bank
      `i` - the index of the requested data array element
    Returns:
      the data array element at the specified index from the specified bank at the specified index.
    See Also:
      - `setElem(int, int)`
      - `setElem(int, int, int)`

  - ### setElem

    public void setElem(int i, int val)
    Sets the requested data array element in the first (default) bank from the given integer.
    Parameters:
      `i` - the specified index into the data array
      `val` - the data to set the element at the specified index in the data array
    See Also:
      - `getElem(int)`
      - `getElem(int, int)`

  - ### setElem

    public abstract void setElem(int bank, int i, int val)
    Sets the requested data array element in the specified bank from the given integer.
    Parameters:
      `bank` - the specified bank
      `i` - the specified index into the data array
      `val` - the data to set the element in the specified bank at the specified index in the data array
    See Also:
      - `getElem(int)`
      - `getElem(int, int)`

  - ### getElemFloat

    public float getElemFloat(int i)
    Returns the requested data array element from the first (default) bank as a float. The implementation in this class is to cast getElem(i) to a float. Subclasses may override this method if another implementation is needed.
    Parameters:
      `i` - the index of the requested data array element
    Returns:
      a float value representing the data array element at the specified index.
    See Also:
      - `setElemFloat(int, float)`
      - `setElemFloat(int, int, float)`

  - ### getElemFloat

    public float getElemFloat(int bank, int i)
    Returns the requested data array element from the specified bank as a float. The implementation in this class is to cast `getElem(int, int)` to a float. Subclasses can override this method if another implementation is needed.
    Parameters:
      `bank` - the specified bank
      `i` - the index of the requested data array element
    Returns:
      a float value representing the data array element from the specified bank at the specified index.
    See Also:
      - `setElemFloat(int, float)`
      - `setElemFloat(int, int, float)`

  - ### setElemFloat

    public void setElemFloat(int i, float val)
    Sets the requested data array element in the first (default) bank from the given float. The implementation in this class is to cast val to an int and call `setElem(int, int)`. Subclasses can override this method if another implementation is needed.
    Parameters:
      `i` - the specified index
      `val` - the value to set the element at the specified index in the data array
    See Also:
      - `getElemFloat(int)`
      - `getElemFloat(int, int)`

  - ### setElemFloat

    public void setElemFloat(int bank, int i, float val)
    Sets the requested data array element in the specified bank from the given float. The implementation in this class is to cast val to an int and call `setElem(int, int)`. Subclasses can override this method if another implementation is needed.
    Parameters:
      `bank` - the specified bank
      `i` - the specified index
      `val` - the value to set the element in the specified bank at the specified index in the data array
    See Also:
      - `getElemFloat(int)`
      - `getElemFloat(int, int)`

  - ### getElemDouble

    public double getElemDouble(int i)
    Returns the requested data array element from the first (default) bank as a double. The implementation in this class is to cast `getElem(int)` to a double. Subclasses can override this method if another implementation is needed.
    Parameters:
      `i` - the specified index
    Returns:
      a double value representing the element at the specified index in the data array.
    See Also:
      - `setElemDouble(int, double)`
      - `setElemDouble(int, int, double)`

  - ### getElemDouble

    public double getElemDouble(int bank, int i)
    Returns the requested data array element from the specified bank as a double. The implementation in this class is to cast getElem(bank, i) to a double. Subclasses may override this method if another implementation is needed.
    Parameters:
      `bank` - the specified bank
      `i` - the specified index
    Returns:
      a double value representing the element from the specified bank at the specified index in the data array.
    See Also:
      - `setElemDouble(int, double)`
      - `setElemDouble(int, int, double)`

  - ### setElemDouble

    public void setElemDouble(int i, double val)
    Sets the requested data array element in the first (default) bank from the given double. The implementation in this class is to cast val to an int and call `setElem(int, int)`. Subclasses can override this method if another implementation is needed.
    Parameters:
      `i` - the specified index
      `val` - the value to set the element at the specified index in the data array
    See Also:
      - `getElemDouble(int)`
      - `getElemDouble(int, int)`

  - ### setElemDouble

    public void setElemDouble(int bank, int i, double val)
    Sets the requested data array element in the specified bank from the given double. The implementation in this class is to cast val to an int and call `setElem(int, int)`. Subclasses can override this method if another implementation is needed.
    Parameters:
      `bank` - the specified bank
      `i` - the specified index
      `val` - the value to set the element in the specified bank at the specified index of the data array
    See Also:
      - `getElemDouble(int)`
      - `getElemDouble(int, int)`