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com.drew.metadata.exif
Class ExifReader
java.lang.Objectcom.drew.metadata.exif.ExifReader
- All Implemented Interfaces:
- com.drew.metadata.MetadataReader
- public class ExifReader
- extends java.lang.Object
- implements com.drew.metadata.MetadataReader
- extends java.lang.Object
Extracts Exif data from a JPEG header segment, providing information about the
camera/scanner/capture device (if available). Information is encapsulated in
an Metadata object.
| Field Summary | |
private byte[] |
_data
The JPEG segment as an array of bytes. |
private com.drew.metadata.Metadata |
_metadata
Bean instance to store information about the image and camera/scanner/capture device. |
(package private) static int[] |
BYTES_PER_FORMAT
The number of bytes used per format descriptor. |
private static int |
FMT_BYTE
|
private static int |
FMT_DOUBLE
|
private static int |
FMT_SBYTE
|
private static int |
FMT_SINGLE
|
private static int |
FMT_SLONG
|
private static int |
FMT_SRATIONAL
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private static int |
FMT_SSHORT
|
private static int |
FMT_STRING
|
private static int |
FMT_ULONG
|
private static int |
FMT_UNDEFINED
|
private static int |
FMT_URATIONAL
|
private static int |
FMT_USHORT
|
private static int |
MAX_FORMAT_CODE
The number of formats known. |
private boolean |
motorollaByteOrder
Represents the native byte ordering used in the JPEG segment. |
static int |
TAG_EXIF_OFFSET
|
static int |
TAG_GPS_INFO_OFFSET
|
static int |
TAG_INTEROP_OFFSET
|
static int |
TAG_MAKER_NOTE
|
static int |
TIFF_HEADER_START_OFFSET
|
| Constructor Summary | |
ExifReader(byte[] data)
Creates an ExifReader for the given JPEG header segment. |
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ExifReader(java.io.File file)
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| Method Summary | |
private int |
calculateDirectoryEntryOffset(int ifdStartOffset,
int entryNumber)
Determine the offset at which a given InteropArray entry begins within the specified IFD. |
private int |
calculateTagValueOffset(int byteCount,
int dirEntryOffset)
|
com.drew.metadata.Metadata |
extract()
Performs the Exif data extraction, returning a new instance of Metadata. |
com.drew.metadata.Metadata |
extract(com.drew.metadata.Metadata metadata)
Performs the Exif data extraction, adding found values to the specified instance of Metadata. |
private void |
extractThumbnail(com.drew.metadata.Directory exifDirectory)
|
private int |
get16Bits(int offset)
Get a 16 bit value from file's native byte order. |
private int |
get32Bits(int offset)
Get a 32 bit value from file's native byte order. |
private boolean |
isDirectoryLengthValid(int dirStartOffset)
|
private void |
processDirectory(com.drew.metadata.Directory directory,
int dirStartOffset)
Process one of the nested EXIF directories. |
private void |
processMakerNote(int subdirOffset)
|
private void |
processTag(com.drew.metadata.Directory directory,
int tagType,
int tagValueOffset,
int componentCount,
int formatCode)
|
private java.lang.String |
readString(int offset,
int maxLength)
Creates a String from the _data buffer starting at the specified offset, and ending where byte=='\0' or where length==maxLength. |
private boolean |
setByteOrder(java.lang.String byteOrderIdentifier)
|
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
_data
private byte[] _data
- The JPEG segment as an array of bytes.
motorollaByteOrder
private boolean motorollaByteOrder
- Represents the native byte ordering used in the JPEG segment. If true,
then we're using Motorolla ordering (Big endian), else we're using Intel
ordering (Little endian).
_metadata
private com.drew.metadata.Metadata _metadata
- Bean instance to store information about the image and camera/scanner/capture
device.
BYTES_PER_FORMAT
static final int[] BYTES_PER_FORMAT
- The number of bytes used per format descriptor.
MAX_FORMAT_CODE
private static final int MAX_FORMAT_CODE
- The number of formats known.
- See Also:
- Constant Field Values
FMT_BYTE
private static final int FMT_BYTE
- See Also:
- Constant Field Values
FMT_STRING
private static final int FMT_STRING
- See Also:
- Constant Field Values
FMT_USHORT
private static final int FMT_USHORT
- See Also:
- Constant Field Values
FMT_ULONG
private static final int FMT_ULONG
- See Also:
- Constant Field Values
FMT_URATIONAL
private static final int FMT_URATIONAL
- See Also:
- Constant Field Values
FMT_SBYTE
private static final int FMT_SBYTE
- See Also:
- Constant Field Values
FMT_UNDEFINED
private static final int FMT_UNDEFINED
- See Also:
- Constant Field Values
FMT_SSHORT
private static final int FMT_SSHORT
- See Also:
- Constant Field Values
FMT_SLONG
private static final int FMT_SLONG
- See Also:
- Constant Field Values
FMT_SRATIONAL
private static final int FMT_SRATIONAL
- See Also:
- Constant Field Values
FMT_SINGLE
private static final int FMT_SINGLE
- See Also:
- Constant Field Values
FMT_DOUBLE
private static final int FMT_DOUBLE
- See Also:
- Constant Field Values
TAG_EXIF_OFFSET
public static final int TAG_EXIF_OFFSET
- See Also:
- Constant Field Values
TAG_INTEROP_OFFSET
public static final int TAG_INTEROP_OFFSET
- See Also:
- Constant Field Values
TAG_GPS_INFO_OFFSET
public static final int TAG_GPS_INFO_OFFSET
- See Also:
- Constant Field Values
TAG_MAKER_NOTE
public static final int TAG_MAKER_NOTE
- See Also:
- Constant Field Values
TIFF_HEADER_START_OFFSET
public static final int TIFF_HEADER_START_OFFSET
- See Also:
- Constant Field Values
| Constructor Detail |
ExifReader
public ExifReader(java.io.File file) throws com.drew.imaging.jpeg.JpegProcessingException, java.io.FileNotFoundException
ExifReader
public ExifReader(byte[] data)
- Creates an ExifReader for the given JPEG header segment.
| Method Detail |
extract
public com.drew.metadata.Metadata extract()
- Performs the Exif data extraction, returning a new instance of
Metadata.- Specified by:
extractin interfacecom.drew.metadata.MetadataReader
extract
public com.drew.metadata.Metadata extract(com.drew.metadata.Metadata metadata)
- Performs the Exif data extraction, adding found values to the specified
instance of
Metadata.- Specified by:
extractin interfacecom.drew.metadata.MetadataReader
extractThumbnail
private void extractThumbnail(com.drew.metadata.Directory exifDirectory)
setByteOrder
private boolean setByteOrder(java.lang.String byteOrderIdentifier)
processDirectory
private void processDirectory(com.drew.metadata.Directory directory, int dirStartOffset)
- Process one of the nested EXIF directories.
processMakerNote
private void processMakerNote(int subdirOffset)
isDirectoryLengthValid
private boolean isDirectoryLengthValid(int dirStartOffset)
processTag
private void processTag(com.drew.metadata.Directory directory, int tagType, int tagValueOffset, int componentCount, int formatCode)
calculateTagValueOffset
private int calculateTagValueOffset(int byteCount,
int dirEntryOffset)
readString
private java.lang.String readString(int offset, int maxLength)
- Creates a String from the _data buffer starting at the specified offset,
and ending where byte=='\0' or where length==maxLength.
calculateDirectoryEntryOffset
private int calculateDirectoryEntryOffset(int ifdStartOffset,
int entryNumber)
- Determine the offset at which a given InteropArray entry begins within the specified IFD.
get16Bits
private int get16Bits(int offset)
- Get a 16 bit value from file's native byte order. Between 0x0000 and 0xFFFF.
get32Bits
private int get32Bits(int offset)
- Get a 32 bit value from file's native byte order.
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DETAIL: FIELD | CONSTR | METHOD | ||||||||