Package javax.imageio.stream
The ImageInputStream interface unifies streaming and file-based
operations. An abstract base class, ImageInputStreamImpl is provided
to simplify writing a new ImageInputStream class. Concrete
implementation classes (FileImageInputStream,
FileCacheImageInputStream, and MemoryCacheImageInputStream)
are provided that allow input to come from a File or
InputStream with or without the use of a temporary cache file.
The ImageOutputStream interface performs an analogous function for
output. An abstract base class, ImageOutputStreamImpl is provided,
along with concrete implementation classes (FileImageOutputStream,
FileCacheImageOutputStream, and MemoryCacheImageOutputStream)
are provided that allow output to go to a File or
OutputStream with or without the use of a temporary cache file.
The IIOByteBuffer class provides an alternative way to perform reads
of sequences of bytes that reduces the amount of internal data copying.
An ImageInputStream or ImageOutputStream may internally allocate
system resources, such as a temporary cache file.
Clients are encouraged to use a try-with-resources statement to ensure the
ImageInputStream.close() or ImageInputStream.close()
method is called which can promptly free those native resources.
Otherwise there is the possibility they will leak and eventually cause the
application to fail as well the possibility that not all data is flushed
to the underlying output stream. A logical consequence of that is that
this should be done before closing the destination OutputStream.
A simple pattern would be
try (FileOutputStream fos = new FileOutputStream("out.jpg");
ImageOutputStream ios = new FileCacheImageOutputStream(fos, null)) {
ImageIO.write(img, "jpg", ios);
} catch (IOException e) {
} // implicit finally block closes the streams in the reverse order to opening
Sub-classers of these Image I/O API stream types can, to a limited extent, protect
the application from the consequences of failures to close by adopting mechanisms
such as Cleaner to free internal resources when it
is no longer reachable. This is only necessary if there are any resources to release.
However applications cannot rely on this, either for resource management, or
for program correctness.
- Since:
- 1.4
-
ClassDescriptionAn implementation of
ImageInputStreamthat gets its input from a regularInputStream.An implementation ofImageOutputStreamthat writes its output to a regularOutputStream.An implementation ofImageInputStreamthat gets its input from aFileorRandomAccessFile.An implementation ofImageOutputStreamthat writes its output directly to aFileorRandomAccessFile.A class representing a mutable reference to an array of bytes and an offset and length within that array.A seekable input stream interface for use byImageReaders.An abstract class implementing theImageInputStreaminterface.A seekable output stream interface for use byImageWriters.An abstract class implementing theImageOutputStreaminterface.An implementation ofImageInputStreamthat gets its input from a regularInputStream.An implementation ofImageOutputStreamthat writes its output to a regularOutputStream.