public final class MemoryCacheSeekableStream extends SeekableStream
SeekableStream that may be used to wrap
a regular InputStream. Seeking backwards is supported
by means of an in-memory cache. For greater efficiency,
FileCacheSeekableStream should be used in
circumstances that allow the creation of a temporary file.
The mark() and reset() methods are
supported.
This class is not a committed part of the JAI API. It may be removed or changed in future releases of JAI.
markPos| Constructor and Description |
|---|
MemoryCacheSeekableStream(java.io.InputStream src)
Constructs a
MemoryCacheSeekableStream that takes
its source data from a regular InputStream. |
| Modifier and Type | Method and Description |
|---|---|
boolean |
canSeekBackwards()
Returns
true since all
MemoryCacheSeekableStream instances support seeking
backwards. |
long |
getFilePointer()
Returns the current offset in this file.
|
int |
read()
Reads the next byte of data from the input stream.
|
int |
read(byte[] b,
int off,
int len)
Reads up to
len bytes of data from the input stream into
an array of bytes. |
void |
seek(long pos)
Sets the file-pointer offset, measured from the beginning of this
file, at which the next read occurs.
|
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, skipBytes, wrapInputStreampublic MemoryCacheSeekableStream(java.io.InputStream src)
MemoryCacheSeekableStream that takes
its source data from a regular InputStream.
Seeking backwards is supported by means of an in-memory cache.public boolean canSeekBackwards()
true since all
MemoryCacheSeekableStream instances support seeking
backwards.canSeekBackwards in class SeekableStreampublic long getFilePointer()
getFilePointer in class SeekableStreampublic void seek(long pos)
throws java.io.IOException
seek in class SeekableStreampos - the offset position, measured in bytes from the
beginning of the file, at which to set the file
pointer.java.io.IOException - if pos is less than
0 or if an I/O error occurs.public int read()
throws java.io.IOException
int in the range 0 to
255. 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.read in class SeekableStream-1 if the end of the
stream is reached.java.io.IOException - if an I/O error occurs.public int read(byte[] b,
int off,
int len)
throws java.io.IOException
len bytes of data from the input stream into
an array of bytes. An attempt is made to read as many as
len 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 file is detected, or an exception is thrown.
If b is null, a
NullPointerException is thrown.
If off is negative, or len is negative, or
off+len is greater than the length of the array
b, then an IndexOutOfBoundsException is
thrown.
If len is zero, then no bytes are read and
0 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
file, the value -1 is returned; otherwise, at least one
byte is read and stored into b.
The first byte read is stored into element b[off], the
next one into b[off+1], and so on. The number of bytes read
is, at most, equal to len. Let k be the number of
bytes actually read; these bytes will be stored in elements
b[off] through b[off+k-1],
leaving elements b[off+k] through
b[off+len-1] unaffected.
In every case, elements b[0] through
b[off] and elements b[off+len] through
b[b.length-1] are unaffected.
If the first byte cannot be read for any reason other than end of
file, then an IOException is thrown. In particular, an
IOException is thrown if the input stream has been closed.
read in class SeekableStreamb - the buffer into which the data is read.off - the start offset in array b
at which the data is written.len - the maximum number of bytes to read.-1 if there is no more data because the end of
the stream has been reached.java.io.IOException - if an I/O error occurs.Copyright 1999-2025 The Apache Software Foundation. All Rights Reserved.