com.sun.media.imageio.plugins.tiff

Class 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 intMAX_DATATYPE
The numerically largest constant representing a TIFF data type.
static intMIN_DATATYPE
The numerically smallest constant representing a TIFF data type.
static intTIFF_ASCII
Flag for null-terminated ASCII strings.
static intTIFF_BYTE
Flag for 8 bit unsigned integers.
static intTIFF_DOUBLE
Flag for 64 bit IEEE doubles.
static intTIFF_FLOAT
Flag for 32 bit IEEE floats.
static intTIFF_IFD_POINTER
Flag for IFD pointer defined in TIFF Tech Note 1 in TIFF Specification Supplement 1.
static intTIFF_LONG
Flag for 32 bit unsigned integers.
static intTIFF_RATIONAL
Flag for pairs of 32 bit unsigned integers.
static intTIFF_SBYTE
Flag for 8 bit signed integers.
static intTIFF_SHORT
Flag for 16 bit unsigned integers.
static intTIFF_SLONG
Flag for 32 bit signed integers.
static intTIFF_SRATIONAL
Flag for pairs of 32 bit signed integers.
static intTIFF_SSHORT
Flag for 16 bit signed integers.
static intTIFF_UNDEFINED
Flag for 8 bit uninterpreted bytes.
Constructor Summary
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.
TIFFTag(String name, int number, int dataTypes)
Constructs a TIFFTag with a given name, tag number, and set of legal data types.
Method Summary
protected voidaddValueName(int value, String name)
Adds a mnemonic name for a particular value that this tag's data may take on.
intgetDataTypes()
Returns a bit mask indicating the set of data types that may be used to store the data associated with the tag.
StringgetName()
Returns the name of the tag, as it will appear in image metadata.
intgetNumber()
Returns the integer used to represent the tag.
static intgetSizeOfType(int dataType)
Returns the number of bytes used to store a value of the given data type.
TIFFTagSetgetTagSet()
Returns the TIFFTagSet of which this tag is a part.
StringgetValueName(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.
booleanhasValueNames()
Returns true if there are mnemonic names associated with the set of legal values for the data associated with this tag.
booleanisDataTypeOK(int dataType)
Returns true if the given data type may be used for the data associated with this tag.
booleanisIFDPointer()
Returns true if this tag is used to point to an IFD structure containing additional tags.

Field Detail

MAX_DATATYPE

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

MIN_DATATYPE

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

TIFF_ASCII

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

TIFF_BYTE

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

TIFF_DOUBLE

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

TIFF_FLOAT

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

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.

TIFF_LONG

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

TIFF_RATIONAL

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

TIFF_SBYTE

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

TIFF_SHORT

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

TIFF_SLONG

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

TIFF_SRATIONAL

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

TIFF_SSHORT

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

TIFF_UNDEFINED

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

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

Method Detail

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.

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.

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.

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.

getTagSet

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

Returns: the containing TIFFTagSet.

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.

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.

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.

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.