This class provides methods and constants for reading and writing jpeg file metadata. It contains a collection of ExifTags, and a collection of definitions for creating valid ExifTags. The collection of ExifTags can be updated by: reading new ones from a file, deleting or adding existing ones, or building new ExifTags from a tag definition. These ExifTags can be written to a valid jpeg image as exif metadata.
Each ExifTag has a tag ID (TID) and is stored in a specific image file directory (IFD) as specified by the exif standard. A tag definition can be looked up with a constant that is a combination of TID and IFD. This definition has information about the type, number of components, and valid IFDs for a ExifTagKey.
This class provides static utility methods for input/output operations.
closeQuietly - these methods close a stream ignoring nulls and exceptions
toXxx/read - these methods read data from a stream
write - these methods write data to a stream
copy - these methods copy all the data from one stream to another
contentEquals - these methods compare the content of two streams
The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production.
All the methods in this class that read a stream are buffered internally. This means that there is no cause to use a BufferedInputStream or BufferedReader. The default buffer size of 4K has been shown to be efficient in tests.
Wherever possible, the methods in this class do not flush or close the stream. This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use.