|Constructor and Description|
|Modifier and Type||Method and Description|
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
Closes this input stream and releases any system resources associated with the stream.
Marks the current position in this input stream.
Tests if this input stream supports the
Reads the next byte of data from the input stream.
Reads up to
Repositions this stream to the position at the time the
Skips over and discards
public LimitedLengthInputStream(InputStream in, int length)
public int available() throws IOException
Note that while some implementations of
InputStream will return the total number of bytes
in the stream, many will not. It is never correct to use the return value of this method to
allocate a buffer intended to hold all data in this stream.
available method for class
InputStream always returns
This method should be overridden by subclasses.
public void close() throws IOException
close method of
InputStream does nothing.
public void mark(int readlimit)
resetmethod repositions this stream at the last marked position so that subsequent reads re-read the same bytes.
readlimit arguments tells this input stream to allow that many bytes to be read
before the mark position gets invalidated.
The general contract of
mark is that, if the method
true, the stream somehow remembers all the bytes read after the call to
mark and stands ready to supply those same bytes again if and whenever the method
reset is called. However, the stream is not required to remember any data at all if
readlimit bytes are read from the stream before
Marking a closed stream should not have any effect on the stream.
mark method of
InputStream does nothing.
public boolean markSupported()
resetmethods. Whether or not
resetare supported is an invariant property of a particular input stream instance. The
public int read() throws IOException
intin the range
255. If no byte is available because the end of the stream has been reached, the value
-1is 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.
public int read(byte b, int off, int len) throws IOException
lenbytes of data from the input stream into an array of bytes. An attempt is made to read as many as
lenbytes, but a smaller number may be read. 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.
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
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 every case, elements
b[off] and elements
b[b.length-1] are unaffected.
len) method for class
InputStream simply calls the method
read() repeatedly. If the first
such call results in an
IOException, that exception is returned from the call to the
len) method. If any subsequent call to
read() results in a
IOException, the exception is caught and treated as
if it were end of file; the bytes read up to that point are stored into
b and the
number of bytes read before the exception occurred is returned. The default implementation of
this method blocks until the requested amount of input data
len has been read, end
of file is detected, or an exception is thrown. Subclasses are encouraged to provide a more
efficient implementation of this method.
b- the buffer into which the data is read.
off- the start offset in array
bat which the data is written.
len- the maximum number of bytes to read.
-1if there is no more data because the end of the stream has been reached.
IOException- If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.
public void reset() throws IOException
markmethod was last called on this input stream.
The general contract of
markhas not been called since the stream was created, or the number of bytes read from the stream since
markwas last called is larger than the argument to
markat that last call, then an
IOExceptionmight be thrown.
IOExceptionis not thrown, then the stream is reset to a state such that all the bytes read since the most recent call to
mark(or since the start of the file, if
markhas not been called) will be resupplied to subsequent callers of the
readmethod, followed by any bytes that otherwise would have been the next input data as of the time of the call to
resetmay throw an
IOExceptionis not thrown, then the stream is reset to a fixed state that depends on the particular type of the input stream and how it was created. The bytes that will be supplied to subsequent callers of the
readmethod depend on the particular type of the input stream.
reset for class
InputStream does nothing except throw an
public long skip(long n) throws IOException
nbytes of data from this input stream. The
skipmethod may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly
0. This may result from any of a number of conditions; reaching end of file before
nbytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If
nis negative, no bytes are skipped.
skip method of this class creates a byte array and then repeatedly reads into it
n bytes have been read or the end of the stream has been reached. Subclasses
are encouraged to provide a more efficient implementation of this method. For instance, the
implementation may depend on the ability to seek.