org.apache.commons.lang
Class BitField

java.lang.Object
  extended byorg.apache.commons.lang.BitField

public class BitField
extends java.lang.Object

Operations on bit-mapped fields.

Since:
2.0
Version:
$Id: BitField.java 437554 2006-08-28 06:21:41Z bayard $
Author:
Apache Jakarta POI, Scott Sanders (sanders at apache dot org), Marc Johnson (mjohnson at apache dot org), Andrew C. Oliver (acoliver at apache dot org), Stephen Colebourne, Pete Gieser, Gary Gregory

Constructor Summary
BitField(int mask)
          Creates a BitField instance.
 
Method Summary
 int clear(int holder)
          Clears the bits.
 byte clearByte(byte holder)
          Clears the bits.
 short clearShort(short holder)
          Clears the bits.
 int getRawValue(int holder)
          Obtains the value for the specified BitField, unshifted.
 short getShortRawValue(short holder)
          Obtains the value for the specified BitField, unshifted.
 short getShortValue(short holder)
          Obtains the value for the specified BitField, appropriately shifted right, as a short.
 int getValue(int holder)
          Obtains the value for the specified BitField, appropriately shifted right.
 boolean isAllSet(int holder)
          Returns whether all of the bits are set or not.
 boolean isSet(int holder)
          Returns whether the field is set or not.
 int set(int holder)
          Sets the bits.
 int setBoolean(int holder, boolean flag)
          Sets a boolean BitField.
 byte setByte(byte holder)
          Sets the bits.
 byte setByteBoolean(byte holder, boolean flag)
          Sets a boolean BitField.
 short setShort(short holder)
          Sets the bits.
 short setShortBoolean(short holder, boolean flag)
          Sets a boolean BitField.
 short setShortValue(short holder, short value)
          Replaces the bits with new values.
 int setValue(int holder, int value)
          Replaces the bits with new values.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BitField

public BitField(int mask)

Creates a BitField instance.

Parameters:
mask - the mask specifying which bits apply to this BitField. Bits that are set in this mask are the bits that this BitField operates on
Method Detail

getValue

public int getValue(int holder)

Obtains the value for the specified BitField, appropriately shifted right.

Many users of a BitField will want to treat the specified bits as an int value, and will not want to be aware that the value is stored as a BitField (and so shifted left so many bits).

Parameters:
holder - the int data containing the bits we're interested in
Returns:
the selected bits, shifted right appropriately
See Also:
setValue(int,int)

getShortValue

public short getShortValue(short holder)

Obtains the value for the specified BitField, appropriately shifted right, as a short.

Many users of a BitField will want to treat the specified bits as an int value, and will not want to be aware that the value is stored as a BitField (and so shifted left so many bits).

Parameters:
holder - the short data containing the bits we're interested in
Returns:
the selected bits, shifted right appropriately
See Also:
setShortValue(short,short)

getRawValue

public int getRawValue(int holder)

Obtains the value for the specified BitField, unshifted.

Parameters:
holder - the int data containing the bits we're interested in
Returns:
the selected bits

getShortRawValue

public short getShortRawValue(short holder)

Obtains the value for the specified BitField, unshifted.

Parameters:
holder - the short data containing the bits we're interested in
Returns:
the selected bits

isSet

public boolean isSet(int holder)

Returns whether the field is set or not.

This is most commonly used for a single-bit field, which is often used to represent a boolean value; the results of using it for a multi-bit field is to determine whether *any* of its bits are set.

Parameters:
holder - the int data containing the bits we're interested in
Returns:
true if any of the bits are set, else false

isAllSet

public boolean isAllSet(int holder)

Returns whether all of the bits are set or not.

This is a stricter test than isSet(int), in that all of the bits in a multi-bit set must be set for this method to return true.

Parameters:
holder - the int data containing the bits we're interested in
Returns:
true if all of the bits are set, else false

setValue

public int setValue(int holder,
                    int value)

Replaces the bits with new values.

Parameters:
holder - the int data containing the bits we're interested in
value - the new value for the specified bits
Returns:
the value of holder with the bits from the value parameter replacing the old bits
See Also:
getValue(int)

setShortValue

public short setShortValue(short holder,
                           short value)

Replaces the bits with new values.

Parameters:
holder - the short data containing the bits we're interested in
value - the new value for the specified bits
Returns:
the value of holder with the bits from the value parameter replacing the old bits
See Also:
getShortValue(short)

clear

public int clear(int holder)

Clears the bits.

Parameters:
holder - the int data containing the bits we're interested in
Returns:
the value of holder with the specified bits cleared (set to 0)

clearShort

public short clearShort(short holder)

Clears the bits.

Parameters:
holder - the short data containing the bits we're interested in
Returns:
the value of holder with the specified bits cleared (set to 0)

clearByte

public byte clearByte(byte holder)

Clears the bits.

Parameters:
holder - the byte data containing the bits we're interested in
Returns:
the value of holder with the specified bits cleared (set to 0)

set

public int set(int holder)

Sets the bits.

Parameters:
holder - the int data containing the bits we're interested in
Returns:
the value of holder with the specified bits set to 1

setShort

public short setShort(short holder)

Sets the bits.

Parameters:
holder - the short data containing the bits we're interested in
Returns:
the value of holder with the specified bits set to 1

setByte

public byte setByte(byte holder)

Sets the bits.

Parameters:
holder - the byte data containing the bits we're interested in
Returns:
the value of holder with the specified bits set to 1

setBoolean

public int setBoolean(int holder,
                      boolean flag)

Sets a boolean BitField.

Parameters:
holder - the int data containing the bits we're interested in
flag - indicating whether to set or clear the bits
Returns:
the value of holder with the specified bits set or cleared

setShortBoolean

public short setShortBoolean(short holder,
                             boolean flag)

Sets a boolean BitField.

Parameters:
holder - the short data containing the bits we're interested in
flag - indicating whether to set or clear the bits
Returns:
the value of holder with the specified bits set or cleared

setByteBoolean

public byte setByteBoolean(byte holder,
                           boolean flag)

Sets a boolean BitField.

Parameters:
holder - the byte data containing the bits we're interested in
flag - indicating whether to set or clear the bits
Returns:
the value of holder with the specified bits set or cleared


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