OpenJDK 27 · javax.imageio.stream.MemoryCacheImageInputStream

public Class MemoryCacheImageInputStream

An implementation of ImageInputStream that gets its input from a regular InputStream. A memory buffer is used to cache at least the data between the discard position and the current read position.

In general, it is preferable to use a FileCacheImageInputStream when reading from a regular InputStream. This class is provided for cases where it is not possible to create a writable temporary file.

Modifier and Type	Field and Description
private MemoryCache	cache
private InputStream	stream

Modifier and Type

Field and Description

private MemoryCache

cache

private InputStream

stream

Constructor Summary

Access	Constructor and Description
public	MemoryCacheImageInputStream(InputStream an `InputStream` to read from. stream) Constructs a `MemoryCacheImageInputStream` that will read from a given `InputStream`.

Modifier and Type	Method and Description
public void	close() Overrides javax.imageio.stream.ImageInputStreamImpl.close. Implements javax.imageio.stream.ImageInputStream.close. Closes this `MemoryCacheImageInputStream`, freeing the cache.
public void	flushBefore(long pos) Overrides javax.imageio.stream.ImageInputStreamImpl.flushBefore. Implements javax.imageio.stream.ImageInputStream.flushBefore. Discards the initial portion of the stream prior to the indicated position.
public boolean	Returns: `true`. isCached() Overrides javax.imageio.stream.ImageInputStreamImpl.isCached. Implements javax.imageio.stream.ImageInputStream.isCached. Returns `true` since this `ImageInputStream` caches data in order to allow seeking backwards.
public boolean	Returns: `false`. isCachedFile() Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedFile. Implements javax.imageio.stream.ImageInputStream.isCachedFile. Returns `false` since this `ImageInputStream` does not maintain a file cache.
public boolean	Returns: `true`. isCachedMemory() Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedMemory. Implements javax.imageio.stream.ImageInputStream.isCachedMemory. Returns `true` since this `ImageInputStream` maintains a main memory cache.
public int	read() Implements abstract javax.imageio.stream.ImageInputStreamImpl.read. Implements javax.imageio.stream.ImageInputStream.read. Reads a single byte from the stream and returns it as an `int` between 0 and 255.
public int	read(byte[] b, int off, int len) Implements abstract javax.imageio.stream.ImageInputStreamImpl.read. Implements javax.imageio.stream.ImageInputStream.read. Reads up to `len` bytes from the stream, and stores them into `b` starting at index `off`.

Modifier and Type

Method and Description

public void

close()

Overrides javax.imageio.stream.ImageInputStreamImpl.close.

Implements javax.imageio.stream.ImageInputStream.close.

Closes this MemoryCacheImageInputStream, freeing the cache.

public void

flushBefore(long pos)

Overrides javax.imageio.stream.ImageInputStreamImpl.flushBefore.

Implements javax.imageio.stream.ImageInputStream.flushBefore.

Discards the initial portion of the stream prior to the indicated position.

public boolean

Returns:

true.

isCached()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCached.

Implements javax.imageio.stream.ImageInputStream.isCached.

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

public boolean

Returns:

false.

isCachedFile()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedFile.

Implements javax.imageio.stream.ImageInputStream.isCachedFile.

Returns false since this ImageInputStream does not maintain a file cache.

public boolean

Returns:

true.

isCachedMemory()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedMemory.

Implements javax.imageio.stream.ImageInputStream.isCachedMemory.

Returns true since this ImageInputStream maintains a main memory cache.

public int

read()

Implements abstract javax.imageio.stream.ImageInputStreamImpl.read.

Implements javax.imageio.stream.ImageInputStream.read.

Reads a single byte from the stream and returns it as an int between 0 and 255.

public int

read(byte[] b, int off, int len)

Implements abstract javax.imageio.stream.ImageInputStreamImpl.read.

Implements javax.imageio.stream.ImageInputStream.read.

Reads up to len bytes from the stream, and stores them into b starting at index off.

cache	back to summary
private MemoryCache cache

cache

back to summary

private MemoryCache cache

stream	back to summary
private InputStream stream

stream

back to summary

private InputStream stream

Constructor Detail

MemoryCacheImageInputStream back to summary

MemoryCacheImageInputStream	back to summary
public MemoryCacheImageInputStream(InputStream stream) Constructs a `MemoryCacheImageInputStream` that will read from a given `InputStream`. Parameters stream:InputStream an `InputStream` to read from. Exceptions IllegalArgumentException: if `stream` is `null`.

public MemoryCacheImageInputStream(InputStream stream)

Constructs a MemoryCacheImageInputStream that will read from a given InputStream.

Parameters

stream:InputStream: an InputStream to read from.

Exceptions

IllegalArgumentException:: if stream is null.

Method Detail

close back to summary

close	back to summary
public void close() throws IOException Overrides javax.imageio.stream.ImageInputStreamImpl.close. Implements javax.imageio.stream.ImageInputStream.close. Closes this `MemoryCacheImageInputStream`, freeing the cache. The source `InputStream` is not closed. Exceptions IOException: Doc from javax.imageio.stream.ImageInputStream.close. if an I/O error occurs.

public void close() throws IOException

Overrides javax.imageio.stream.ImageInputStreamImpl.close.

Implements javax.imageio.stream.ImageInputStream.close.

Closes this MemoryCacheImageInputStream, freeing the cache. The source InputStream is not closed.

Exceptions

IOException:

Doc from javax.imageio.stream.ImageInputStream.close.

if an I/O error occurs.

flushBefore back to summary

flushBefore	back to summary
public void flushBefore(long pos) throws IOException Overrides javax.imageio.stream.ImageInputStreamImpl.flushBefore. Implements javax.imageio.stream.ImageInputStream.flushBefore. Doc from javax.imageio.stream.ImageInputStream.flushBefore. Discards the initial portion of the stream prior to the indicated position. Attempting to seek to an offset within the flushed portion of the stream will result in an `IndexOutOfBoundsException`. Calling `flushBefore` may allow classes implementing this interface to free up resources such as memory or disk space that are being used to store data from the stream. Exceptions IOException: if an I/O error occurs.

public void flushBefore(long pos) throws IOException

Overrides javax.imageio.stream.ImageInputStreamImpl.flushBefore.

Implements javax.imageio.stream.ImageInputStream.flushBefore.

Doc from javax.imageio.stream.ImageInputStream.flushBefore.

Discards the initial portion of the stream prior to the indicated position. Attempting to seek to an offset within the flushed portion of the stream will result in an IndexOutOfBoundsException.

Calling flushBefore may allow classes implementing this interface to free up resources such as memory or disk space that are being used to store data from the stream.

Exceptions

IOException:: if an I/O error occurs.

isCached back to summary

isCached	back to summary
public boolean isCached() Overrides javax.imageio.stream.ImageInputStreamImpl.isCached. Implements javax.imageio.stream.ImageInputStream.isCached. Returns `true` since this `ImageInputStream` caches data in order to allow seeking backwards. Returns:boolean `true`. See Also `isCachedMemory`, `isCachedFile`

public boolean isCached()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCached.

Implements javax.imageio.stream.ImageInputStream.isCached.

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

Returns:boolean: true.
See Also: isCachedMemory, isCachedFile

isCachedFile back to summary

isCachedFile	back to summary
public boolean isCachedFile() Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedFile. Implements javax.imageio.stream.ImageInputStream.isCachedFile. Returns `false` since this `ImageInputStream` does not maintain a file cache. Returns:boolean `false`. See Also `isCached`, `isCachedMemory`

public boolean isCachedFile()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedFile.

Implements javax.imageio.stream.ImageInputStream.isCachedFile.

Returns false since this ImageInputStream does not maintain a file cache.

Returns:boolean: false.
See Also: isCached, isCachedMemory

isCachedMemory back to summary

isCachedMemory	back to summary
public boolean isCachedMemory() Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedMemory. Implements javax.imageio.stream.ImageInputStream.isCachedMemory. Returns `true` since this `ImageInputStream` maintains a main memory cache. Returns:boolean `true`. See Also `isCached`, `isCachedFile`

public boolean isCachedMemory()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedMemory.

Implements javax.imageio.stream.ImageInputStream.isCachedMemory.

Returns true since this ImageInputStream maintains a main memory cache.

Returns:boolean: true.
See Also: isCached, isCachedFile

read back to summary

read	back to summary
public int read() throws IOException Implements abstract javax.imageio.stream.ImageInputStreamImpl.read. Implements javax.imageio.stream.ImageInputStream.read. Doc from javax.imageio.stream.ImageInputStreamImpl.read. 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. Exceptions IOException: if the stream has been closed.

public int read() throws IOException

Implements abstract javax.imageio.stream.ImageInputStreamImpl.read.

Implements javax.imageio.stream.ImageInputStream.read.

Doc from javax.imageio.stream.ImageInputStreamImpl.read.

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.

Exceptions

IOException:: if the stream has been closed.

read back to summary

read	back to summary
public int read(byte[] b, int off, int len) throws IOException Implements abstract javax.imageio.stream.ImageInputStreamImpl.read. Implements javax.imageio.stream.ImageInputStream.read. Doc from javax.imageio.stream.ImageInputStreamImpl.read. 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. Exceptions IOException: if an I/O error occurs.

public int read(byte[] b, int off, int len) throws IOException

Implements abstract javax.imageio.stream.ImageInputStreamImpl.read.

Implements javax.imageio.stream.ImageInputStream.read.

Doc from javax.imageio.stream.ImageInputStreamImpl.read.

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.

Exceptions

IOException:: if an I/O error occurs.

public Class MemoryCacheImageInputStream

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail