- java.lang.Object
-
- javax.imageio.stream.ImageInputStreamImpl
-
- All Implemented Interfaces:
Closeable,DataInput,AutoCloseable,ImageInputStream
- Direct Known Subclasses:
FileCacheImageInputStream,FileImageInputStream,ImageOutputStreamImpl,MemoryCacheImageInputStream
public abstract class ImageInputStreamImpl extends Object implements ImageInputStream
An abstract class implementing theImageInputStreaminterface. This class is designed to reduce the number of methods that must be implemented by subclasses.In particular, this class handles most or all of the details of byte order interpretation, buffering, mark/reset, discarding, closing, and disposing.
-
-
Field Summary
Fields Modifier and Type Field Description protected intbitOffsetThe current bit offset within the stream.protected ByteOrderbyteOrderThe byte order of the stream as an instance of the enumeration classjava.nio.ByteOrder, whereByteOrder.BIG_ENDIANindicates network byte order andByteOrder.LITTLE_ENDIANindicates the reverse order.protected longflushedPosThe position prior to which data may be discarded.protected longstreamPosThe current read position within the stream.
-
Constructor Summary
Constructors Constructor Description ImageInputStreamImpl()Constructs anImageInputStreamImpl.
-
Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods Modifier and Type Method Description protected voidcheckClosed()Throws anIOExceptionif the stream has been closed.protected voidfinalize()Deprecated.Thefinalizemethod has been deprecated.booleanisCached()Default implementation returns false.booleanisCachedFile()Default implementation returns false.booleanisCachedMemory()Default implementation returns false.longlength()Returns-1Lto indicate that the stream has unknown length.voidmark()Pushes the current stream position onto a stack of marked positions.abstract intread()Reads a single byte from the stream and returns it as anintbetween 0 and 255.intread(byte[] b)A convenience method that callsread(b, 0, b.length).abstract intread(byte[] b, int off, int len)Reads up tolenbytes from the stream, and stores them intobstarting at indexoff.voidreset()Resets the current stream byte and bit positions from the stack of marked positions.intskipBytes(int n)Advances the current stream position by callingseek(getStreamPosition() + n).longskipBytes(long n)Advances the current stream position by callingseek(getStreamPosition() + n).-
Methods declared in class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
-
Methods declared in interface javax.imageio.stream.ImageInputStream
close, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, seek, setBitOffset, setByteOrder
-
-
-
-
Field Detail
-
byteOrder
protected ByteOrder byteOrder
The byte order of the stream as an instance of the enumeration classjava.nio.ByteOrder, whereByteOrder.BIG_ENDIANindicates network byte order andByteOrder.LITTLE_ENDIANindicates the reverse order. By default, the value isByteOrder.BIG_ENDIAN.
-
streamPos
protected long streamPos
The current read position within the stream. Subclasses are responsible for keeping this value current from any method they override that alters the read position.
-
bitOffset
protected int bitOffset
The current bit offset within the stream. Subclasses are responsible for keeping this value current from any method they override that alters the bit offset.
-
flushedPos
protected long flushedPos
The position prior to which data may be discarded. Seeking to a smaller position is not allowed.flushedPoswill always be >= 0.
-
-
Method Detail
-
checkClosed
protected final void checkClosed() throws IOExceptionThrows anIOExceptionif the stream has been closed. Subclasses may call this method from any of their methods that require the stream not to be closed.- Throws:
IOException- if the stream is closed.
-
read
public abstract int read() throws IOExceptionReads a single byte from the stream and returns it as anintbetween 0 and 255. If EOF is reached,-1is 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:
readin interfaceImageInputStream- Returns:
- the value of the next byte in the stream, or
-1if EOF is reached. - Throws:
IOException- if the stream has been closed.
-
read
public int read(byte[] b) throws IOExceptionA convenience method that callsread(b, 0, b.length).The bit offset within the stream is reset to zero before the read occurs.
- Specified by:
readin interfaceImageInputStream- Parameters:
b- an array of bytes to be written to.- Returns:
- the number of bytes actually read, or
-1to indicate EOF. - Throws:
NullPointerException- ifbisnull.IOException- if an I/O error occurs.
-
read
public abstract int read(byte[] b, int off, int len) throws IOExceptionReads up tolenbytes from the stream, and stores them intobstarting at indexoff. If no bytes can be read because the end of the stream has been reached,-1is 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:
readin interfaceImageInputStream- Parameters:
b- an array of bytes to be written to.off- the starting position withinbto write to.len- the maximum number of bytes to read.- Returns:
- the number of bytes actually read, or
-1to indicate EOF. - Throws:
IndexOutOfBoundsException- ifoffis negative,lenis negative, oroff + lenis greater thanb.length.NullPointerException- ifbisnull.IOException- if an I/O error occurs.
-
length
public long length()
Returns-1Lto indicate that the stream has unknown length. Subclasses must override this method to provide actual length information.- Specified by:
lengthin interfaceImageInputStream- Returns:
- -1L to indicate unknown length.
-
skipBytes
public int skipBytes(int n) throws IOExceptionAdvances the current stream position by callingseek(getStreamPosition() + n).The bit offset is reset to zero.
- Specified by:
skipBytesin interfaceDataInput- Specified by:
skipBytesin interfaceImageInputStream- Parameters:
n- the number of bytes to seek forward.- Returns:
- an
intrepresenting the number of bytes skipped. - Throws:
IOException- ifgetStreamPositionthrows anIOExceptionwhen computing either the starting or ending position.
-
skipBytes
public long skipBytes(long n) throws IOExceptionAdvances the current stream position by callingseek(getStreamPosition() + n).The bit offset is reset to zero.
- Specified by:
skipBytesin interfaceImageInputStream- Parameters:
n- the number of bytes to seek forward.- Returns:
- a
longrepresenting the number of bytes skipped. - Throws:
IOException- ifgetStreamPositionthrows anIOExceptionwhen computing either the starting or ending position.
-
mark
public void mark()
Pushes the current stream position onto a stack of marked positions.- Specified by:
markin interfaceImageInputStream
-
reset
public void reset() throws IOExceptionResets the current stream byte and bit positions from the stack of marked positions.An
IOExceptionwill be thrown if the previous marked position lies in the discarded portion of the stream.- Specified by:
resetin interfaceImageInputStream- Throws:
IOException- if an I/O error occurs.
-
isCached
public boolean isCached()
Default implementation returns false. Subclasses should override this if they cache data.- Specified by:
isCachedin interfaceImageInputStream- Returns:
trueif thisImageInputStreamcaches data.- See Also:
ImageInputStream.isCachedMemory(),ImageInputStream.isCachedFile()
-
isCachedMemory
public boolean isCachedMemory()
Default implementation returns false. Subclasses should override this if they cache data in main memory.- Specified by:
isCachedMemoryin interfaceImageInputStream- Returns:
trueif thisImageInputStreamcaches data in main memory.- See Also:
ImageInputStream.isCached(),ImageInputStream.isCachedFile()
-
isCachedFile
public boolean isCachedFile()
Default implementation returns false. Subclasses should override this if they cache data in a temporary file.- Specified by:
isCachedFilein interfaceImageInputStream- Returns:
trueif thisImageInputStreamcaches data in a temporary file.- See Also:
ImageInputStream.isCached(),ImageInputStream.isCachedMemory()
-
finalize
@Deprecated(since="9") protected void finalize() throws Throwable
Deprecated.Thefinalizemethod has been deprecated. Subclasses that overridefinalizein order to perform cleanup should be modified to use alternative cleanup mechanisms and to remove the overridingfinalizemethod. When overriding thefinalizemethod, its implementation must explicitly ensure thatsuper.finalize()is invoked as described inObject.finalize(). See the specification forObject.finalize()for further information about migration options.Finalizes this object prior to garbage collection. Theclosemethod is called to close any open input source. This method should not be called from application code.
-
-