public class FileImageInputStream extends ImageInputStreamImpl
An implementation of ImageInputStream
that gets its input from a File
or RandomAccessFile
. The file contents are assumed to be stable during the lifetime of the object.
bitOffset, byteOrder, flushedPos, streamPos
public FileImageInputStream(File f) throws FileNotFoundException, IOException
Constructs a FileImageInputStream
that will read from a given File
.
The file contents must not change between the time this object is constructed and the time of the last call to a read method.
f
- a File
to read from.IllegalArgumentException
- if f
is null
.SecurityException
- if a security manager exists and does not allow read access to the file.FileNotFoundException
- if f
is a directory or cannot be opened for reading for any other reason.IOException
- if an I/O error occurs.public FileImageInputStream(RandomAccessFile raf)
Constructs a FileImageInputStream
that will read from a given RandomAccessFile
.
The file contents must not change between the time this object is constructed and the time of the last call to a read method.
raf
- a RandomAccessFile
to read from.IllegalArgumentException
- if raf
is null
.public int read() throws IOException
Description copied from class: ImageInputStreamImpl
Reads a single byte from the stream and returns it as an int
between 0 and 255. If EOF is reached, -1
is returned.
Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
The bit offset within the stream must be reset to zero before the read occurs.
read
in interface ImageInputStream
read
in class ImageInputStreamImpl
-1
if EOF is reached.IOException
- if the stream has been closed.public int read(byte[] b, int off, int len) throws IOException
Description copied from class: ImageInputStreamImpl
Reads up to len
bytes from the stream, and stores them into b
starting at index off
. If no bytes can be read because the end of the stream has been reached, -1
is returned.
The bit offset within the stream must be reset to zero before the read occurs.
Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
read
in interface ImageInputStream
read
in class ImageInputStreamImpl
b
- an array of bytes to be written to.off
- the starting position within b
to write to.len
- the maximum number of bytes to read.-1
to indicate EOF.IOException
- if an I/O error occurs.public long length()
Returns the length of the underlying file, or -1
if it is unknown.
length
in interface ImageInputStream
length
in class ImageInputStreamImpl
long
, or -1
.public void seek(long pos) throws IOException
Description copied from interface: ImageInputStream
Sets the current stream position to the desired location. The next read will occur at this location. The bit offset is set to 0.
An IndexOutOfBoundsException
will be thrown if pos
is smaller than the flushed position (as returned by getflushedPosition
).
It is legal to seek past the end of the file; an java.io.EOFException
will be thrown only if a read is performed.
seek
in interface ImageInputStream
seek
in class ImageInputStreamImpl
pos
- a long
containing the desired file pointer position.IOException
- if any other I/O error occurs.public void close() throws IOException
Description copied from interface: ImageInputStream
Closes the stream. Attempts to access a stream that has been closed may result in IOException
s or incorrect behavior. Calling this method may allow classes implementing this interface to release resources associated with the stream such as memory, disk space, or file descriptors.
close
in interface Closeable
close
in interface AutoCloseable
close
in interface ImageInputStream
close
in class ImageInputStreamImpl
IOException
- if an I/O error occurs.protected void finalize() throws Throwable
Finalizes this object prior to garbage collection. The close
method is called to close any open input source. This method should not be called from application code.
finalize
in class ImageInputStreamImpl
Throwable
- if an error occurs during superclass finalization.WeakReference
, PhantomReference
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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