public class MemoryCacheImageInputStream extends ImageInputStreamImpl
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.
bitOffset, byteOrder, flushedPos, streamPos| Constructor and Description |
|---|
MemoryCacheImageInputStream(InputStream stream)
Constructs a
MemoryCacheImageInputStream that will read
from a given InputStream. |
| Modifier and Type | Method and Description |
|---|---|
void |
close()
Closes this
MemoryCacheImageInputStream, freeing
the cache. |
protected void |
finalize()
Finalizes this object prior to garbage collection.
|
void |
flushBefore(long pos)
Discards the initial portion of the stream prior to the
indicated postion.
|
boolean |
isCached()
Returns
true since this
ImageInputStream caches data in order to allow
seeking backwards. |
boolean |
isCachedFile()
Returns
false since this
ImageInputStream does not maintain a file cache. |
boolean |
isCachedMemory()
Returns
true since this
ImageInputStream maintains 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. |
checkClosed, flush, 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, skipBytespublic MemoryCacheImageInputStream(InputStream stream)
MemoryCacheImageInputStream that will read
from a given InputStream.stream - an InputStream to read from.IllegalArgumentException - if stream is
null.public int read()
throws IOException
ImageInputStreamImplint 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.
read in interface ImageInputStreamread in class ImageInputStreamImpl-1
if EOF is reached.IOException - if the stream has been closed.public int read(byte[] b,
int off,
int len)
throws IOException
ImageInputStreamImpllen 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.
read in interface ImageInputStreamread in class ImageInputStreamImplb - 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.-1
to indicate EOF.IOException - if an I/O error occurs.public void flushBefore(long pos)
throws IOException
ImageInputStreamIndexOutOfBoundsException.
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.
flushBefore in interface ImageInputStreamflushBefore in class ImageInputStreamImplpos - a long containing the length of the
stream prefix that may be flushed.IOException - if an I/O error occurs.public boolean isCached()
true since this
ImageInputStream caches data in order to allow
seeking backwards.isCached in interface ImageInputStreamisCached in class ImageInputStreamImpltrue.isCachedMemory(),
isCachedFile()public boolean isCachedFile()
false since this
ImageInputStream does not maintain a file cache.isCachedFile in interface ImageInputStreamisCachedFile in class ImageInputStreamImplfalse.isCached(),
isCachedMemory()public boolean isCachedMemory()
true since this
ImageInputStream maintains a main memory cache.isCachedMemory in interface ImageInputStreamisCachedMemory in class ImageInputStreamImpltrue.isCached(),
isCachedFile()public void close()
throws IOException
MemoryCacheImageInputStream, freeing
the cache. The source InputStream is not closed.close in interface Closeableclose in interface AutoCloseableclose in interface ImageInputStreamclose in class ImageInputStreamImplIOException - if an I/O error occurs.protected void finalize()
throws Throwable
close method is called to close any open input
source. This method should not be called from application
code.finalize in class ImageInputStreamImplThrowable - if an error occurs during superclass
finalization.