MemoryCacheImageOutputStream (Java Platform SE 6) (original) (raw)

javax.imageio.stream

Class MemoryCacheImageOutputStream

java.lang.Object extended by javax.imageio.stream.ImageInputStreamImpl extended by javax.imageio.stream.ImageOutputStreamImpl extended by javax.imageio.stream.MemoryCacheImageOutputStream

All Implemented Interfaces:

DataInput, DataOutput, ImageInputStream, ImageOutputStream

public class MemoryCacheImageOutputStream

extends ImageOutputStreamImpl

An implementation of ImageOutputStream that writes its output to a regular OutputStream. A memory buffer is used to cache at least the data between the discard position and the current write position. The only constructor takes an OutputStream, so this class may not be used for read/modify/write operations. Reading can occur only on parts of the stream that have already been written to the cache and not yet flushed.

Field Summary
Fields inherited from class javax.imageio.stream.ImageInputStreamImpl
bitOffset, byteOrder, flushedPos, streamPos
Constructor Summary
MemoryCacheImageOutputStream(OutputStream stream) Constructs a MemoryCacheImageOutputStream that will write to a given OutputStream.
Method Summary
void close() Closes this MemoryCacheImageOutputStream.
void flushBefore(long pos) Discards the initial portion of the stream prior to the indicated postion.
boolean isCached() Returns true since thisImageOutputStream caches data in order to allow seeking backwards.
boolean isCachedFile() Returns false since thisImageOutputStream does not maintain a file cache.
boolean isCachedMemory() Returns true since thisImageOutputStream maintains a main memory cache.
long length() Returns -1L to indicate that the stream has unknown length.
int read() Reads a single byte from the stream and returns it as anint between 0 and 255.
int [read](../../../javax/imageio/stream/MemoryCacheImageOutputStream.html#read%28byte[], int, int%29)(byte[] b, int off, int len) Reads up to len bytes from the stream, and stores them into b starting at index off.
void [write](../../../javax/imageio/stream/MemoryCacheImageOutputStream.html#write%28byte[], int, int%29)(byte[] b, int off, int len) Writes a sequence of bytes to the stream at the current position.
void write(int b) Writes a single byte to the stream at the current position.
Methods inherited from class javax.imageio.stream.ImageOutputStreamImpl
flushBits, write, writeBit, [writeBits](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeBits%28long, int%29), writeBoolean, writeByte, writeBytes, writeChar, [writeChars](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeChars%28char[], int, int%29), writeChars, writeDouble, [writeDoubles](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeDoubles%28double[], int, int%29), writeFloat, [writeFloats](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeFloats%28float[], int, int%29), writeInt, [writeInts](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeInts%28int[], int, int%29), writeLong, [writeLongs](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeLongs%28long[], int, int%29), writeShort, [writeShorts](../../../javax/imageio/stream/ImageOutputStreamImpl.html#writeShorts%28short[], int, int%29), writeUTF
Methods inherited from class javax.imageio.stream.ImageInputStreamImpl
checkClosed, finalize, flush, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, mark, read, readBit, readBits, readBoolean, readByte, [readBytes](../../../javax/imageio/stream/ImageInputStreamImpl.html#readBytes%28javax.imageio.stream.IIOByteBuffer, int%29), readChar, readDouble, readFloat, readFully, [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28byte[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28char[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28double[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28float[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28int[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28long[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStreamImpl.html#readFully%28short[], int, int%29), 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](../../../java/lang/Object.html#wait%28long, int%29)
Methods inherited from interface javax.imageio.stream.ImageInputStream
flush, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, mark, read, readBit, readBits, readBoolean, readByte, [readBytes](../../../javax/imageio/stream/ImageInputStream.html#readBytes%28javax.imageio.stream.IIOByteBuffer, int%29), readChar, readDouble, readFloat, readFully, [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28byte[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28char[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28double[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28float[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28int[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28long[], int, int%29), [readFully](../../../javax/imageio/stream/ImageInputStream.html#readFully%28short[], int, int%29), readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, seek, setBitOffset, setByteOrder, skipBytes, skipBytes
Constructor Detail

MemoryCacheImageOutputStream

public MemoryCacheImageOutputStream(OutputStream stream)

Constructs a MemoryCacheImageOutputStream that will write to a given OutputStream.

Parameters:

stream - an OutputStream to write to.

Throws:

[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - if stream isnull.

Method Detail

read

public int read() throws IOException

Description copied from class: [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28%29)

Reads a single byte from the stream and returns it as anint 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](../../../javax/imageio/stream/ImageInputStream.html#read%28%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Specified by:

[read](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Returns:

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

Throws:

[IOException](../../../java/io/IOException.html "class in java.io") - if the stream has been closed.

read

public int read(byte[] b, int off, int len) throws IOException

Description copied from class: [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28byte[], int, int%29)

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](../../../javax/imageio/stream/ImageInputStream.html#read%28byte[], int, int%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Specified by:

[read](../../../javax/imageio/stream/ImageInputStreamImpl.html#read%28byte[], int, int%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

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](../../../java/io/IOException.html "class in java.io") - if an I/O error occurs.

write

public void write(int b) throws IOException

Description copied from interface: [ImageOutputStream](../../../javax/imageio/stream/ImageOutputStream.html#write%28int%29)

Writes a single byte to the stream at the current position. The 24 high-order bits of b are ignored.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write. Implementers can use the flushBits method of ImageOutputStreamImpl to guarantee this.

Specified by:

[write](../../../java/io/DataOutput.html#write%28int%29) in interface [DataOutput](../../../java/io/DataOutput.html "interface in java.io")

Specified by:

[write](../../../javax/imageio/stream/ImageOutputStream.html#write%28int%29) in interface [ImageOutputStream](../../../javax/imageio/stream/ImageOutputStream.html "interface in javax.imageio.stream")

Specified by:

[write](../../../javax/imageio/stream/ImageOutputStreamImpl.html#write%28int%29) in class [ImageOutputStreamImpl](../../../javax/imageio/stream/ImageOutputStreamImpl.html "class in javax.imageio.stream")

Parameters:

b - an int whose lower 8 bits are to be written.

Throws:

[IOException](../../../java/io/IOException.html "class in java.io") - if an I/O error occurs.

write

public void write(byte[] b, int off, int len) throws IOException

Description copied from interface: [ImageOutputStream](../../../javax/imageio/stream/ImageOutputStream.html#write%28byte[], int, int%29)

Writes a sequence of bytes to the stream at the current position. If len is 0, nothing is written. The byte b[off] is written first, then the byteb[off + 1], and so on.

If the bit offset within the stream is non-zero, the remainder of the current byte is padded with 0s and written out first. The bit offset will be 0 after the write. Implementers can use the flushBits method of ImageOutputStreamImpl to guarantee this.

Specified by:

[write](../../../java/io/DataOutput.html#write%28byte[], int, int%29) in interface [DataOutput](../../../java/io/DataOutput.html "interface in java.io")

Specified by:

[write](../../../javax/imageio/stream/ImageOutputStream.html#write%28byte[], int, int%29) in interface [ImageOutputStream](../../../javax/imageio/stream/ImageOutputStream.html "interface in javax.imageio.stream")

Specified by:

[write](../../../javax/imageio/stream/ImageOutputStreamImpl.html#write%28byte[], int, int%29) in class [ImageOutputStreamImpl](../../../javax/imageio/stream/ImageOutputStreamImpl.html "class in javax.imageio.stream")

Parameters:

b - an array of bytes to be written.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

[IOException](../../../java/io/IOException.html "class in java.io") - if an I/O error occurs.

length

public long length()

Description copied from class: [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html#length%28%29)

Returns -1L to indicate that the stream has unknown length. Subclasses must override this method to provide actual length information.

Specified by:

[length](../../../javax/imageio/stream/ImageInputStream.html#length%28%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Overrides:

[length](../../../javax/imageio/stream/ImageInputStreamImpl.html#length%28%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Returns:

-1L to indicate unknown length.

isCached

public boolean isCached()

Returns true since thisImageOutputStream caches data in order to allow seeking backwards.

Specified by:

[isCached](../../../javax/imageio/stream/ImageInputStream.html#isCached%28%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Overrides:

[isCached](../../../javax/imageio/stream/ImageInputStreamImpl.html#isCached%28%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Returns:

true.

See Also:

isCachedMemory(), isCachedFile()

isCachedFile

public boolean isCachedFile()

Returns false since thisImageOutputStream does not maintain a file cache.

Specified by:

[isCachedFile](../../../javax/imageio/stream/ImageInputStream.html#isCachedFile%28%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Overrides:

[isCachedFile](../../../javax/imageio/stream/ImageInputStreamImpl.html#isCachedFile%28%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Returns:

false.

See Also:

isCached(), isCachedMemory()

isCachedMemory

public boolean isCachedMemory()

Returns true since thisImageOutputStream maintains a main memory cache.

Specified by:

[isCachedMemory](../../../javax/imageio/stream/ImageInputStream.html#isCachedMemory%28%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Overrides:

[isCachedMemory](../../../javax/imageio/stream/ImageInputStreamImpl.html#isCachedMemory%28%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Returns:

true.

See Also:

isCached(), isCachedFile()

close

public void close() throws IOException

Closes this MemoryCacheImageOutputStream. All pending data is flushed to the output, and the cache is released. The destination OutputStream is not closed.

Specified by:

[close](../../../javax/imageio/stream/ImageInputStream.html#close%28%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Overrides:

[close](../../../javax/imageio/stream/ImageInputStreamImpl.html#close%28%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Throws:

[IOException](../../../java/io/IOException.html "class in java.io") - if an I/O error occurs.

flushBefore

public void flushBefore(long pos) throws IOException

Description copied from interface: [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html#flushBefore%28long%29)

Discards the initial portion of the stream prior to the indicated postion. Attempting to seek to an offset within the flushed portion of the stream will result in anIndexOutOfBoundsException.

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](../../../javax/imageio/stream/ImageInputStream.html#flushBefore%28long%29) in interface [ImageInputStream](../../../javax/imageio/stream/ImageInputStream.html "interface in javax.imageio.stream")

Specified by:

[flushBefore](../../../javax/imageio/stream/ImageOutputStream.html#flushBefore%28long%29) in interface [ImageOutputStream](../../../javax/imageio/stream/ImageOutputStream.html "interface in javax.imageio.stream")

Overrides:

[flushBefore](../../../javax/imageio/stream/ImageInputStreamImpl.html#flushBefore%28long%29) in class [ImageInputStreamImpl](../../../javax/imageio/stream/ImageInputStreamImpl.html "class in javax.imageio.stream")

Parameters:

pos - a long containing the length of the stream prefix that may be flushed.

Throws:

[IOException](../../../java/io/IOException.html "class in java.io") - if an I/O error occurs.

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