Class FileCacheImageOutputStream

All Implemented Interfaces:
Closeable, DataInput, DataOutput, AutoCloseable, ImageInputStream, ImageOutputStream 
public class FileCacheImageOutputStream
extends ImageOutputStreamImpl

An implementation of ImageOutputStream that writes its output to a regular OutputStream. A file is used to cache data until it is flushed to the output stream.

Fields

Fields declared in class javax.imageio.stream.ImageInputStreamImpl

bitOffset, byteOrder, flushedPos, streamPos

Constructors

Constructor Description
FileCacheImageOutputStream​(OutputStream stream, File cacheDir)

Constructs a FileCacheImageOutputStream that will write to a given outputStream.

Methods

Modifier and Type Method Description
void close()

Closes this FileCacheImageOutputStream.
boolean isCached()

Returns true since this ImageOutputStream caches data in order to allow seeking backwards.
boolean isCachedFile()

Returns true since this ImageOutputStream maintains a file cache.
boolean isCachedMemory()

Returns false since this ImageOutputStream does not maintain a main memory cache.
void seek​(long pos)

Sets the current stream position and resets the bit offset to 0.

Methods declared in class javax.imageio.stream.ImageOutputStreamImpl

flushBits

Methods declared in class javax.imageio.stream.ImageInputStreamImpl

checkClosed, finalize, length, mark, read, read, read, reset, skipBytes, skipBytes

Methods declared in class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods declared in interface javax.imageio.stream.ImageInputStream

flush, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, length, mark, read, read, read, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, setBitOffset, setByteOrder, skipBytes, skipBytes

Methods declared in interface javax.imageio.stream.ImageOutputStream

flushBefore, write, write, write, writeBit, writeBits, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeChars, writeDouble, writeDoubles, writeFloat, writeFloats, writeInt, writeInts, writeLong, writeLongs, writeShort, writeShorts, writeUTF

Constructors

FileCacheImageOutputStream

public FileCacheImageOutputStream(OutputStream stream,
                                  File cacheDir)
                           throws IOException

Constructs a FileCacheImageOutputStream that will write to a given outputStream.

A temporary file is used as a cache. If cacheDir is non-null and is a directory, the file will be created there. If it is null, the system-dependent default temporary-file directory will be used (see the documentation for File.createTempFile for details).

Parameters:
stream - an OutputStream to write to.
cacheDir - a File indicating where the cache file should be created, or null to use the system directory.
Throws:
IllegalArgumentException - if stream is null.
IllegalArgumentException - if cacheDir is non-null but is not a directory.
IOException - if a cache file cannot be created.

Methods

seek

public void seek(long pos)
          throws IOException

Sets the current stream position and resets the bit offset to 0. It is legal to seek past the end of the file; an EOFException will be thrown only if a read is performed. The file length will not be increased until a write is performed.

Parameters:
pos - a long containing the desired file pointer position.
Throws:
IndexOutOfBoundsException - if pos is smaller than the flushed position.
IOException - if any other I/O error occurs.

isCached

public boolean isCached()

Returns true since this ImageOutputStream caches data in order to allow seeking backwards.

Specified by:
isCached in interface ImageInputStream
Overrides:
isCached in class ImageInputStreamImpl
Returns:
true.
See Also:
isCachedMemory(), isCachedFile()

isCachedFile

public boolean isCachedFile()

Returns true since this ImageOutputStream maintains a file cache.

Specified by:
isCachedFile in interface ImageInputStream
Overrides:
isCachedFile in class ImageInputStreamImpl
Returns:
true.
See Also:
isCached(), isCachedMemory()

isCachedMemory

public boolean isCachedMemory()

Returns false since this ImageOutputStream does not maintain a main memory cache.

Specified by:
isCachedMemory in interface ImageInputStream
Overrides:
isCachedMemory in class ImageInputStreamImpl
Returns:
false.
See Also:
isCached(), isCachedFile()

close

public void close()
           throws IOException

Closes this FileCacheImageOutputStream. All pending data is flushed to the output, and the cache file is closed and removed. The destination OutputStream is not closed.

Throws:
IOException - if an error occurs.

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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.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/imageio/stream/FileCacheImageOutputStream.html