All Implemented Interfaces:

Closeable, DataInput, AutoCloseable, ImageInputStream

public class FileCacheImageInputStream
extends ImageInputStreamImpl 

• Field Summary

  • Fields inherited from class javax.imageio.stream.ImageInputStreamImpl

    bitOffset, byteOrder, flushedPos, streamPos

• Constructor Summary

  Constructors

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

• Method Summary

  Methods

  Modifier and Type	Method and Description
  void	close () Closes this FileCacheImageInputStream, closing and removing the cache file.
  protected void	finalize () Finalizes this object prior to garbage collection.
  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.
  int	read () Reads a single byte from the stream and returns it as an int between 0 and 255.
  int	read (byte[] b, int off, int len) Reads up to len bytes from the stream, and stores them into b starting at index off.

  • Methods inherited from class javax.imageio.stream.ImageInputStreamImpl

    checkClosed, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, length, mark, 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, seek, setBitOffset, setByteOrder, skipBytes, skipBytes

  • Methods inherited from class java.lang.Object

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

• Constructor Detail

  • 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 cacheDiris 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.

• Method Detail

  • read

    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.

    Specified by:

    read in interface ImageInputStream

    Specified by:

    read in class ImageInputStreamImpl

    Returns:

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

    Throws:

    IOException - if the stream has been closed.

  • read

    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.

    Specified by:

    read in interface ImageInputStream

    Specified by:

    read in class ImageInputStreamImpl

    Parameters:

    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.

    Returns:

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

    Throws:

    IOException - if an I/O error occurs.

  • 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.

    Specified by:

    close in interface Closeable

    Specified by:

    close in interface AutoCloseable

    Specified by:

    close in interface ImageInputStream

    Overrides:

    close in class ImageInputStreamImpl

    Throws:

    IOException - if an error occurs.

  • finalize

    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.

    Overrides:

    finalize in class ImageInputStreamImpl

    Throws:

    Throwable - if an error occurs during superclass finalization.