Module java.desktop
Package javax.imageio.stream

Class MemoryCacheImageInputStream

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

    public class MemoryCacheImageInputStream
extends ImageInputStreamImpl
    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.

    • Constructor Detail

      • MemoryCacheImageInputStream

        public MemoryCacheImageInputStream​(InputStream stream)
        Constructs a MemoryCacheImageInputStream that will read from a given InputStream.
        Parameters:
        stream - an InputStream to read from.
        Throws:
        IllegalArgumentException - if stream is null.

    • 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.

      • flushBefore

        public void flushBefore​(long pos)
                 throws IOException
        Description copied from interface: ImageInputStream
        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.

        Specified by:
        flushBefore in interface ImageInputStream
        Overrides:
        flushBefore in class ImageInputStreamImpl
        Parameters:
        pos - a long containing the length of the stream prefix that may be flushed.
        Throws:
        IOException - if an I/O 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