Class FileCacheImageInputStream

java.lang.Object
- javax.imageio.stream.ImageInputStreamImpl
- - javax.imageio.stream.FileCacheImageInputStream

All Implemented Interfaces:: Closeable, DataInput, AutoCloseable, ImageInputStream

public class FileCacheImageInputStream
extends ImageInputStreamImpl

An implementation of ImageInputStream that gets its input from a regular InputStream. A file is used to cache previously read data.

Fields

Fields declared in class javax.imageio.stream.ImageInputStreamImpl

bitOffset, byteOrder, flushedPos, streamPos

Constructors

Constructor	Description
`FileCacheImageInputStream(InputStream stream, File cacheDir)`	Constructs a `FileCacheImageInputStream` that will read from a given `InputStream`.

Methods

Modifier and Type	Method	Description
`void`	`close()`	Closes this `FileCacheImageInputStream`, closing and removing the cache file.
`protected void`	`finalize()`	Deprecated. The `finalize` method has been deprecated.
`boolean`	`isCached()`	Returns `true` since this `ImageInputStream` caches data in order to allow seeking backwards.
`boolean`	`isCachedFile()`	Returns `true` since this `ImageInputStream` maintains a file cache.
`boolean`	`isCachedMemory()`	Returns `false` since this `ImageInputStream` does not maintain a main memory cache.

Methods declared in class javax.imageio.stream.ImageInputStreamImpl

checkClosed, 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, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, seek, setBitOffset, setByteOrder

Constructors

FileCacheImageInputStream

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 - an InputStream to read from.; 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

isCached

public boolean isCached()

Returns true since this ImageInputStream 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 ImageInputStream 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 ImageInputStream 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 FileCacheImageInputStream, closing and removing the cache file. The source InputStream is not closed.

Throws:: IOException - if an error occurs.

finalize

@Deprecated(since="9")
protected void finalize()
                 throws Throwable

Deprecated.

The finalize method has been deprecated. Subclasses that override finalize in order to perform cleanup should be modified to use alternative cleanup mechanisms and to remove the overriding finalize method. When overriding the finalize method, its implementation must explicitly ensure that super.finalize() is invoked as described in Object.finalize(). See the specification for Object.finalize() for further information 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.

Overrides:: finalize in class ImageInputStreamImpl
Throws:: Throwable - if an error occurs during superclass finalization.
See Also:: WeakReference, PhantomReference

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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/imageio/stream/FileCacheImageInputStream.html