Module java.desktop

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.
  • Constructor Details

    • 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).

      stream - an OutputStream to write to.
      cacheDir - a File indicating where the cache file should be created, or null to use the system directory.
      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 Details

    • 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.
      pos - a long containing the desired file pointer position.
      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
      isCached in class ImageInputStreamImpl
      See Also:
      isCachedMemory(), isCachedFile()
    • isCachedFile

      public boolean isCachedFile()
      Returns true since this ImageOutputStream maintains a file cache.
      Specified by:
      isCachedFile in interface ImageInputStream
      isCachedFile in class ImageInputStreamImpl
      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
      isCachedMemory in class ImageInputStreamImpl
      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.
      IOException - if an error occurs.