@Beta @GwtIncompatible public final class CountingInputStream extends FilterInputStream
InputStream
that counts the number of bytes read.in
Constructor and Description |
---|
CountingInputStream(InputStream in)
Wraps another input stream, counting the number of bytes read.
|
Modifier and Type | Method and Description |
---|---|
long |
getCount()
Returns the number of bytes read.
|
void |
mark(int readlimit)
Marks the current position in this input stream.
|
int |
read()
Reads the next byte of data from this input stream.
|
int |
read(byte[] b,
int off,
int len)
Reads up to
len bytes of data from this input stream
into an array of bytes. |
void |
reset()
Repositions this stream to the position at the time the
mark method was last called on this input stream. |
long |
skip(long n)
Skips over and discards
n bytes of data from the
input stream. |
available, close, markSupported, read
public CountingInputStream(InputStream in)
in
- the input stream to be wrappedpublic long getCount()
public int read() throws IOException
java.io.FilterInputStream
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.
This method
simply performs in.read()
and returns the result.
read
in class FilterInputStream
-1
if the end of the
stream is reached.IOException
- if an I/O error occurs.FilterInputStream.in
public int read(byte[] b, int off, int len) throws IOException
java.io.FilterInputStream
len
bytes of data from this input stream
into an array of bytes. If len
is not zero, the method
blocks until some input is available; otherwise, no
bytes are read and 0
is returned.
This method simply performs in.read(b, off, len)
and returns the result.
read
in class FilterInputStream
b
- the buffer into which the data is read.off
- the start offset in the destination array b
len
- the maximum number of bytes read.-1
if there is no more data because the end of
the stream has been reached.IOException
- if an I/O error occurs.FilterInputStream.in
public long skip(long n) throws IOException
java.io.FilterInputStream
n
bytes of data from the
input stream. The skip
method may, for a variety of
reasons, end up skipping over some smaller number of bytes,
possibly 0
. The actual number of bytes skipped is
returned.
This method simply performs in.skip(n)
.
skip
in class FilterInputStream
n
- the number of bytes to be skipped.IOException
- if the stream does not support seek,
or if some other I/O error occurs.public void mark(int readlimit)
java.io.FilterInputStream
reset
method repositions this stream at
the last marked position so that subsequent reads re-read the same bytes.
The readlimit
argument tells this input stream to
allow that many bytes to be read before the mark position gets
invalidated.
This method simply performs in.mark(readlimit)
.
mark
in class FilterInputStream
readlimit
- the maximum limit of bytes that can be read before
the mark position becomes invalid.FilterInputStream.in
,
FilterInputStream.reset()
public void reset() throws IOException
java.io.FilterInputStream
mark
method was last called on this input stream.
This method
simply performs in.reset()
.
Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.
reset
in class FilterInputStream
IOException
- if the stream has not been marked or if the
mark has been invalidated.FilterInputStream.in
,
FilterInputStream.mark(int)
Copyright © 2010–2019. All rights reserved.