Class SeekableStreamAdapter
- All Implemented Interfaces:
Closeable
,DataInput
,AutoCloseable
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Field Summary
Fields inherited from class org.apache.xmlgraphics.image.codec.util.SeekableStream
markPos
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionboolean
Returnstrue
if this object supports calls toseek(pos)
with an offsetpos
smaller than the current offset, as returned bygetFilePointer
.long
Returns the current offset in this stream.int
read()
Reads the next byte of data from the input stream.int
read
(byte[] b, int off, int len) Reads up tolen
bytes of data from the input stream into an array of bytes.void
seek
(long pos) Sets the offset, measured from the beginning of this stream, at which the next read occurs.int
skipBytes
(int n) Attempts to skip overn
bytes of input discarding the skipped bytes.Methods inherited from class org.apache.xmlgraphics.image.codec.util.SeekableStream
finalize, mark, markSupported, readBoolean, readByte, readChar, readCharLE, readDouble, readDoubleLE, readFloat, readFloatLE, readFully, readFully, readInt, readIntLE, readLine, readLong, readLongLE, readShort, readShortLE, readUnsignedByte, readUnsignedInt, readUnsignedIntLE, readUnsignedShort, readUnsignedShortLE, readUTF, reset, wrapInputStream
Methods inherited from class java.io.InputStream
available, close, nullInputStream, read, readAllBytes, readNBytes, readNBytes, skip, skipNBytes, transferTo
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Constructor Details
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SeekableStreamAdapter
Main constructor- Parameters:
iin
- the ImageInputStream to operate on
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Method Details
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getFilePointer
Returns the current offset in this stream.- Specified by:
getFilePointer
in classSeekableStream
- Returns:
- the offset from the beginning of the stream, in bytes, at which the next read occurs.
- Throws:
IOException
- if an I/O error occurs.
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read
Reads the next byte of data from the input stream. The value byte is returned as anint
in the range0
to255
. If no byte is available because the end of the stream has been reached, the value-1
is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.A subclass must provide an implementation of this method.
- Specified by:
read
in classSeekableStream
- Returns:
- the next byte of data, or
-1
if the end of the stream is reached. - Throws:
IOException
- if an I/O error occurs.
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read
Reads up tolen
bytes of data from the input stream into an array of bytes. An attempt is made to read as many aslen
bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.This method blocks until input data is available, end of stream is detected, or an exception is thrown.
If
b
isnull
, aNullPointerException
is thrown.If
off
is negative, orlen
is negative, oroff+len
is greater than the length of the arrayb
, then anIndexOutOfBoundsException
is thrown.If
len
is zero, then no bytes are read and0
is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of stream, the value-1
is returned; otherwise, at least one byte is read and stored intob
.The first byte read is stored into element
b[off]
, the next one intob[off+1]
, and so on. The number of bytes read is, at most, equal tolen
. Let k be the number of bytes actually read; these bytes will be stored in elementsb[off]
throughb[off+
k-1]
, leaving elementsb[off+
k]
throughb[off+len-1]
unaffected.In every case, elements
b[0]
throughb[off]
and elementsb[off+len]
throughb[b.length-1]
are unaffected.If the first byte cannot be read for any reason other than end of stream, then an
IOException
is thrown. In particular, anIOException
is thrown if the input stream has been closed.A subclass must provide an implementation of this method.
- Specified by:
read
in classSeekableStream
- Parameters:
b
- the buffer into which the data is read.off
- the start offset in arrayb
at which the data is written.len
- the maximum number of bytes to read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the stream has been reached. - Throws:
IOException
- if an I/O error occurs.
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seek
Sets the offset, measured from the beginning of this stream, at which the next read occurs.If
canSeekBackwards()
returnsfalse
, then settingpos
to an offset smaller than the current value ofgetFilePointer()
will have no effect.- Specified by:
seek
in classSeekableStream
- Parameters:
pos
- the offset position, measured in bytes from the beginning of the stream, at which to set the stream pointer.- Throws:
IOException
- ifpos
is less than0
or if an I/O error occurs.
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canSeekBackwards
public boolean canSeekBackwards()Returnstrue
if this object supports calls toseek(pos)
with an offsetpos
smaller than the current offset, as returned bygetFilePointer
.- Overrides:
canSeekBackwards
in classSeekableStream
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skipBytes
Attempts to skip overn
bytes of input discarding the skipped bytes.This method may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of stream before
n
bytes have been skipped is only one possibility. This method never throws anEOFException
. The actual number of bytes skipped is returned. Ifn
is negative, no bytes are skipped.- Specified by:
skipBytes
in interfaceDataInput
- Overrides:
skipBytes
in classSeekableStream
- Parameters:
n
- the number of bytes to be skipped.- Returns:
- the actual number of bytes skipped.
- Throws:
IOException
- if an I/O error occurs.
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