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:

Field Summary

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

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

TYPE_USHORT

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

TYPE_SHORT

@Native public static final int TYPE_SHORT
Tag for signed short data. Placeholder for future use.
See Also:

TYPE_INT

@Native public static final int TYPE_INT
Tag for int data.
See Also:

TYPE_FLOAT

@Native public static final int TYPE_FLOAT
Tag for float data. Placeholder for future use.
See Also:

TYPE_DOUBLE

@Native public static final int TYPE_DOUBLE
Tag for double data. Placeholder for future use.
See Also:

TYPE_UNDEFINED

@Native public static final int TYPE_UNDEFINED
Tag for undefined data.
See Also:

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:

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

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:

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:

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:

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

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:

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:

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:

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

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:

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:

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https://docs.oracle.com/en/java/javase/17/docs/api/java.desktop/java/awt/image/DataBuffer.html