OpenJDK 1.23 · javax.imageio.stream.FileCacheImageInputStream

Modifier and Type	Class and Description
private static class	FileCacheImageInputStream.StreamDisposerRecord

Modifier and Type	Field and Description
private byte[]	buf
private static final int	BUFFER_LENGTH
private RandomAccessFile	cache
private File	cacheFile
private final StreamCloser.CloseAction	closeAction The CloseAction that closes the stream in the StreamCloser's shutdown hook
private final DisposerRecord	disposerRecord The DisposerRecord that closes the underlying cache.
private final Object	disposerReferent The referent to be registered with the Disposer.
private boolean	foundEOF
private long	length
private InputStream	stream

Access	Constructor and Description
public	FileCacheImageInputStream(InputStream an `InputStream` to read from. stream, File a `File` indicating where the cache file should be created, or `null` to use the system directory. cacheDir) Constructs a `FileCacheImageInputStream` that will read from a given `InputStream`.

Method Summary

Modifier and Type	Method and Description
public void	close() Overrides javax.imageio.stream.ImageInputStreamImpl.close. Implements javax.imageio.stream.ImageInputStream.close. Closes this `FileCacheImageInputStream`, closing and removing the cache file.
protected void	finalize() Overrides javax.imageio.stream.ImageInputStreamImpl.finalize. Deprecated for removal since 9. Finalization has been deprecated for removal. See `java.lang.Object#finalize` for background information and details about migration options. Finalizes this object prior to garbage collection.
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: `true`. isCachedFile() Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedFile. Implements javax.imageio.stream.ImageInputStream.isCachedFile. Returns `true` since this `ImageInputStream` maintains a file cache.
public boolean	Returns: `false`. isCachedMemory() Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedMemory. Implements javax.imageio.stream.ImageInputStream.isCachedMemory. Returns `false` since this `ImageInputStream` does not maintain 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[] an array of bytes to be written to. b, int the starting position within `b` to write to. off, int the maximum number of bytes to read. 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`.
private long	readUntil(long pos) Ensures that at least `pos` bytes are cached, or the end of the source is reached.

Field Detail

buf	back to summary
private byte[] buf

BUFFER_LENGTH	back to summary
private static final int BUFFER_LENGTH

cache	back to summary
private RandomAccessFile cache

cacheFile	back to summary
private File cacheFile

closeAction	back to summary
private final StreamCloser.CloseAction closeAction The CloseAction that closes the stream in the StreamCloser's shutdown hook

disposerRecord	back to summary
private final DisposerRecord disposerRecord The DisposerRecord that closes the underlying cache.

disposerReferent	back to summary
private final Object disposerReferent The referent to be registered with the Disposer.

foundEOF	back to summary
private boolean foundEOF

length	back to summary
private long length

stream	back to summary
private InputStream stream

Constructor Detail

FileCacheImageInputStream back to summary

FileCacheImageInputStream	back to summary
public FileCacheImageInputStream(InputStream stream, File cacheDir) throws IOException Constructs a `FileCacheImageInputStream` that will read from a given `InputStream`. 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:InputStream an `InputStream` to read from. cacheDir:File a `File` indicating where the cache file should be created, or `null` to use the system directory. Exceptions IOException: if a cache file cannot be created. IllegalArgumentException: if `stream` is `null`. if `cacheDir` is non-`null` but is not a directory.

public FileCacheImageInputStream(InputStream stream, File cacheDir) throws IOException

Constructs a FileCacheImageInputStream that will read from a given InputStream.

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:InputStream: an InputStream to read from.
cacheDir:File: a File indicating where the cache file should be created, or null to use the system directory.

Exceptions

IOException:

if a cache file cannot be created.

IllegalArgumentException:

if stream is null.
if cacheDir is non-null but is not a directory.

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 `FileCacheImageInputStream`, closing and removing the cache file. The source `InputStream` is not closed. Exceptions IOException: if an error occurs.

public void close() throws IOException

Overrides javax.imageio.stream.ImageInputStreamImpl.close.

Implements javax.imageio.stream.ImageInputStream.close.

Closes this FileCacheImageInputStream, closing and removing the cache file. The source InputStream is not closed.

Exceptions

IOException:: if an error occurs.

finalize back to summary

finalize	back to summary
protected void finalize() throws Throwable Overrides javax.imageio.stream.ImageInputStreamImpl.finalize. Doc from javax.imageio.stream.ImageInputStreamImpl.finalize. Deprecated for removal since 9. Finalization has been deprecated for removal. See `java.lang.Object#finalize` for background information and details about migration options. 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. Annotations @Deprecated since:9 forRemoval:true @SuppressWarnings:removal Exceptions Throwable: if an error occurs during superclass finalization.

protected void finalize() throws Throwable

Overrides javax.imageio.stream.ImageInputStreamImpl.finalize.

Doc from javax.imageio.stream.ImageInputStreamImpl.finalize.

Deprecated

for removal since 9.

Finalization has been deprecated for removal. See java.lang.Object#finalize for background information and details about migration options.

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.

Annotations

@Deprecated
since:9
forRemoval:true
@SuppressWarnings:removal

Exceptions

Throwable:: if an error occurs during superclass finalization.

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 `true` since this `ImageInputStream` maintains a file cache. Returns:boolean `true`. See Also `isCached`, `isCachedMemory`

public boolean isCachedFile()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedFile.

Implements javax.imageio.stream.ImageInputStream.isCachedFile.

Returns true since this ImageInputStream maintains a file cache.

Returns:boolean: true.
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 `false` since this `ImageInputStream` does not maintain a main memory cache. Returns:boolean `false`. See Also `isCached`, `isCachedFile`

public boolean isCachedMemory()

Overrides javax.imageio.stream.ImageInputStreamImpl.isCachedMemory.

Implements javax.imageio.stream.ImageInputStream.isCachedMemory.

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

Returns:boolean: false.
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. Returns:int the value of the next byte in the stream, or `-1` if EOF is reached. 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.

Returns:int

the value of the next byte in the stream, or -1 if EOF is reached.

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. Parameters b:byte[] an array of bytes to be written to. off:int the starting position within `b` to write to. len:int the maximum number of bytes to read. Returns:int the number of bytes actually read, or `-1` to indicate EOF. 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.

Parameters

b:byte[]: an array of bytes to be written to.
off:int: the starting position within b to write to.
len:int: the maximum number of bytes to read.

Returns:int

the number of bytes actually read, or -1 to indicate EOF.

Exceptions

IOException:: if an I/O error occurs.

readUntil back to summary

readUntil	back to summary
private long readUntil(long pos) throws IOException Ensures that at least `pos` bytes are cached, or the end of the source is reached. The return value is equal to the smaller of `pos` and the length of the source file. Exceptions IOException: if an I/O error occurs while reading from the source file

private long readUntil(long pos) throws IOException

Ensures that at least pos bytes are cached, or the end of the source is reached. The return value is equal to the smaller of pos and the length of the source file.

Exceptions

IOException:: if an I/O error occurs while reading from the source file

public Class FileCacheImageInputStream

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private Class FileCacheImageInputStream.StreamDisposerRecord

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