com.sun.media.imageio.plugins.tiff
Class TIFFTag

java.lang.Object
  extended bycom.sun.media.imageio.plugins.tiff.TIFFTag

public class TIFFTag
extends Object

A class defining the notion of a TIFF tag. A TIFF tag is a key that may appear in an Image File Directory (IFD). In the IFD each tag has some data associated with it, which may consist of zero or more values of a given data type. The combination of a tag and a value is known as an IFD Entry or TIFF Field.

The actual tag values used in the root IFD of a standard ("baseline") tiff stream are defined in the BaselineTIFFTagSet class.

See Also:
BaselineTIFFTagSet, TIFFField, TIFFTagSet

Field Summary
static int MAX_DATATYPE
          The numerically largest constant representing a TIFF data type.
static int MIN_DATATYPE
          The numerically smallest constant representing a TIFF data type.
static int TIFF_ASCII
          Flag for null-terminated ASCII strings.
static int TIFF_BYTE
          Flag for 8 bit unsigned integers.
static int TIFF_DOUBLE
          Flag for 64 bit IEEE doubles.
static int TIFF_FLOAT
          Flag for 32 bit IEEE floats.
static int TIFF_IFD_POINTER
          Flag for IFD pointer defined in TIFF Tech Note 1 in TIFF Specification Supplement 1.
static int TIFF_LONG
          Flag for 32 bit unsigned integers.
static int TIFF_RATIONAL
          Flag for pairs of 32 bit unsigned integers.
static int TIFF_SBYTE
          Flag for 8 bit signed integers.
static int TIFF_SHORT
          Flag for 16 bit unsigned integers.
static int TIFF_SLONG
          Flag for 32 bit signed integers.
static int TIFF_SRATIONAL
          Flag for pairs of 32 bit signed integers.
static int TIFF_SSHORT
          Flag for 16 bit signed integers.
static int TIFF_UNDEFINED
          Flag for 8 bit uninterpreted bytes.
 
Constructor Summary
TIFFTag(String name, int number, int dataTypes)
          Constructs a TIFFTag with a given name, tag number, and set of legal data types.
TIFFTag(String name, int number, int dataTypes, TIFFTagSet tagSet)
          Constructs a TIFFTag with a given name, tag number, set of legal data types, and TIFFTagSet to which it refers.
 
Method Summary
protected  void addValueName(int value, String name)
          Adds a mnemonic name for a particular value that this tag's data may take on.
 int getDataTypes()
          Returns a bit mask indicating the set of data types that may be used to store the data associated with the tag.
 String getName()
          Returns the name of the tag, as it will appear in image metadata.
 int getNumber()
          Returns the integer used to represent the tag.
static int getSizeOfType(int dataType)
          Returns the number of bytes used to store a value of the given data type.
 TIFFTagSet getTagSet()
          Returns the TIFFTagSet of which this tag is a part.
 String getValueName(int value)
          Returns the mnemonic name associated with a particular value that this tag's data may take on, or null if no name is present.
 boolean hasValueNames()
          Returns true if there are mnemonic names associated with the set of legal values for the data associated with this tag.
 boolean isDataTypeOK(int dataType)
          Returns true if the given data type may be used for the data associated with this tag.
 boolean isIFDPointer()
          Returns true if this tag is used to point to an IFD structure containing additional tags.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

TIFF_BYTE

public static final int TIFF_BYTE
Flag for 8 bit unsigned integers.

See Also:
Constant Field Values

TIFF_ASCII

public static final int TIFF_ASCII
Flag for null-terminated ASCII strings.

See Also:
Constant Field Values

TIFF_SHORT

public static final int TIFF_SHORT
Flag for 16 bit unsigned integers.

See Also:
Constant Field Values

TIFF_LONG

public static final int TIFF_LONG
Flag for 32 bit unsigned integers.

See Also:
Constant Field Values

TIFF_RATIONAL

public static final int TIFF_RATIONAL
Flag for pairs of 32 bit unsigned integers.

See Also:
Constant Field Values

TIFF_SBYTE

public static final int TIFF_SBYTE
Flag for 8 bit signed integers.

See Also:
Constant Field Values

TIFF_UNDEFINED

public static final int TIFF_UNDEFINED
Flag for 8 bit uninterpreted bytes.

See Also:
Constant Field Values

TIFF_SSHORT

public static final int TIFF_SSHORT
Flag for 16 bit signed integers.

See Also:
Constant Field Values

TIFF_SLONG

public static final int TIFF_SLONG
Flag for 32 bit signed integers.

See Also:
Constant Field Values

TIFF_SRATIONAL

public static final int TIFF_SRATIONAL
Flag for pairs of 32 bit signed integers.

See Also:
Constant Field Values

TIFF_FLOAT

public static final int TIFF_FLOAT
Flag for 32 bit IEEE floats.

See Also:
Constant Field Values

TIFF_DOUBLE

public static final int TIFF_DOUBLE
Flag for 64 bit IEEE doubles.

See Also:
Constant Field Values

TIFF_IFD_POINTER

public static final int TIFF_IFD_POINTER
Flag for IFD pointer defined in TIFF Tech Note 1 in TIFF Specification Supplement 1.

See Also:
Constant Field Values

MIN_DATATYPE

public static final int MIN_DATATYPE
The numerically smallest constant representing a TIFF data type.

See Also:
Constant Field Values

MAX_DATATYPE

public static final int MAX_DATATYPE
The numerically largest constant representing a TIFF data type.

See Also:
Constant Field Values
Constructor Detail

TIFFTag

public TIFFTag(String name,
               int number,
               int dataTypes,
               TIFFTagSet tagSet)
Constructs a TIFFTag with a given name, tag number, set of legal data types, and TIFFTagSet to which it refers. The tagSet parameter will generally be non-null only if this TIFFTag corresponds to a pointer to a TIFF IFD. In this case tagSet will represent the set of TIFFTags which appear in the IFD pointed to. A TIFFTag represents an IFD pointer if and only if tagSet is non-null or the data type TIFF_IFD_POINTER is legal.

If there are mnemonic names to be associated with the legal data values for the tag, addValueName() should be called on the new instance for each name.

See the documentation for getDataTypes() for an explanation of how the set of data types is to be converted into a bit mask.

Parameters:
name - the name of the tag; may be null.
number - the number used to represent the tag.
dataTypes - a bit mask indicating the set of legal data types for this tag.
tagSet - the TIFFTagSet to which this tag belongs; may be null.

TIFFTag

public TIFFTag(String name,
               int number,
               int dataTypes)
Constructs a TIFFTag with a given name, tag number, and set of legal data types. The tag will have no associated TIFFTagSet.

Parameters:
name - the name of the tag; may be null.
number - the number used to represent the tag.
dataTypes - a bit mask indicating the set of legal data types for this tag.
See Also:
TIFFTag(String, int, int, TIFFTagSet)
Method Detail

getSizeOfType

public static int getSizeOfType(int dataType)
Returns the number of bytes used to store a value of the given data type.

Parameters:
dataType - the data type to be queried.
Returns:
the number of bytes used to store the given data type.
Throws:
IllegalArgumentException - if datatype is less than MIN_DATATYPE or greater than MAX_DATATYPE.

getName

public String getName()
Returns the name of the tag, as it will appear in image metadata.

Returns:
the tag name, as a String.

getNumber

public int getNumber()
Returns the integer used to represent the tag.

Returns:
the tag number, as an int.

getDataTypes

public int getDataTypes()
Returns a bit mask indicating the set of data types that may be used to store the data associated with the tag. For example, a tag that can store both SHORT and LONG values would return a value of:
 (1 << TIFFTag.TIFF_SHORT) | (1 << TIFFTag.TIFF_LONG)
 

Returns:
an int containing a bitmask encoding the set of valid data types.

isDataTypeOK

public boolean isDataTypeOK(int dataType)
Returns true if the given data type may be used for the data associated with this tag.

Parameters:
dataType - the data type to be queried, one of TIFF_BYTE, TIFF_SHORT, etc.
Returns:
a boolean indicating whether the given data type may be used with this tag.
Throws:
IllegalArgumentException - if datatype is less than MIN_DATATYPE or greater than MAX_DATATYPE.

getTagSet

public TIFFTagSet getTagSet()
Returns the TIFFTagSet of which this tag is a part.

Returns:
the containing TIFFTagSet.

isIFDPointer

public boolean isIFDPointer()
Returns true if this tag is used to point to an IFD structure containing additional tags. This condition will be satisfied if and only if either getTagSet() != null or isDataTypeOK(TIFF_IFD_POINTER) == true.

Many TIFF extensions use this mechanism in order to limit the number of new tags that may appear in the root IFD.

Returns:
true if this tag points to an IFD.

hasValueNames

public boolean hasValueNames()
Returns true if there are mnemonic names associated with the set of legal values for the data associated with this tag.

Returns:
true if mnemonic value names are available.

addValueName

protected void addValueName(int value,
                            String name)
Adds a mnemonic name for a particular value that this tag's data may take on.

Parameters:
value - the data value.
name - the name to associate with the value.

getValueName

public String getValueName(int value)
Returns the mnemonic name associated with a particular value that this tag's data may take on, or null if no name is present.

Parameters:
value - the data value.
Returns:
the mnemonic name associated with the value, as a String.