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java.awt.image
Class DataBuffer

java.lang.Object
  |
  +--java.awt.image.DataBuffer

Direct Known Subclasses:

DataBufferByte, 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 API image classes use only TYPE_BYTE, TYPE_USHORT, and TYPE_INT DataBuffers to store image data.

See Also:

Raster, SampleModel

Field Summary

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 int	TYPE_BYTE Tag for unsigned byte data.
static int	TYPE_DOUBLE Tag for double data.
static int	TYPE_FLOAT Tag for float data.
static int	TYPE_INT Tag for int data.
static int	TYPE_SHORT Tag for signed short data.
static int	TYPE_UNDEFINED Tag for undefined data
static int	TYPE_USHORT Tag for unsigned short data.

Constructor Summary

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

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 inherited from class java.lang.Object

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

Field Detail

TYPE_BYTE

public static final int TYPE_BYTE

Tag for unsigned byte data.

TYPE_USHORT

public static final int TYPE_USHORT

Tag for unsigned short data.

TYPE_SHORT

public static final int TYPE_SHORT

Tag for signed short data. Placeholder for future use.

TYPE_INT

public static final int TYPE_INT

Tag for int data.

TYPE_FLOAT

public static final int TYPE_FLOAT

Tag for float data. Placeholder for future use.

TYPE_DOUBLE

public static final int TYPE_DOUBLE

Tag for double data. Placeholder for future use.

TYPE_UNDEFINED

public static final int TYPE_UNDEFINED

Tag for undefined data

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 Detail

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 Detail

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.

getSize

public int getSize()

Returns the size (in array elements) of all banks.

getOffset

public int getOffset()

Returns the offset of the default bank in array elements.

getOffsets

public int[] getOffsets()

Returns the offsets (in array elements) of all the banks.

getNumBanks

public int getNumBanks()

Returns the number of banks in this DataBuffer.

getElem

public int getElem(int i)

Returns the requested data array element from the first (default) bank as an integer.

getElem

public abstract int getElem(int bank,
                            int i)

Returns the requested data array element from the specified bank as an integer.

setElem

public void setElem(int i,
                    int val)

Sets the requested data array element in the first (default) bank from the given integer.

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.

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.

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(bank, i) to a float. Subclasses may override this method if another implementation is needed.

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. Subclasses may override this method if another implementation is needed.

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. Subclasses may override this method if another implementation is needed.

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(i) to a double. Subclasses may override this method if another implementation is needed.

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.

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. Subclasses may override this method if another implementation is needed.

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. Subclasses may override this method if another implementation is needed.