public class ArbitraryDataInputStream
extends java.io.InputStream
| Constructor and Description |
|---|
ArbitraryDataInputStream(java.io.DataInput dataInput)
Create an new ArbitraryDataInputStream wrapper around the specified DataInput.
|
| Modifier and Type | Method and Description |
|---|---|
void |
mark(int readlimit)
Marks the current position in this input stream.
|
boolean |
markSupported()
Tests if this input stream supports the
mark and
reset methods. |
int |
read()
Reads the next byte of data from the input stream.
|
int |
read(byte[] b)
Reads some number of bytes from the input stream and stores them into
the buffer array
b. |
int |
read(byte[] b,
int off,
int len)
Reads up to
len bytes of data from the input stream into
an array of bytes. |
public ArbitraryDataInputStream(java.io.DataInput dataInput)
dataInput - dataInput implementor to wrappublic 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.
A subclass must provide an implementation of this method.
read in class java.io.InputStream-1 if the end of the
stream is reached.java.io.IOException - if an I/O error occurs.public void mark(int readlimit)
reset method repositions this stream at the last marked
position so that subsequent reads re-read the same bytes.
The 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
markSupported returns 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 more than readlimit bytes are
read from the stream before reset is called.
Marking a closed stream should not have any effect on the stream.
The mark method of InputStream does
nothing.
mark in class java.io.InputStreamreadlimit - the maximum limit of bytes that can be read before
the mark position becomes invalid.InputStream.reset()public boolean markSupported()
mark and
reset methods. Whether or not mark and
reset are supported is an invariant property of a
particular input stream instance. The markSupported method
of InputStream returns false.markSupported in class java.io.InputStreamtrue if this stream instance supports the mark
and reset methods; false otherwise.InputStream.mark(int),
InputStream.reset()public int read(byte[] b)
throws java.io.IOException
b. 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 the length of b 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 the
end of the 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[0], the
next one into b[1], and so on. The number of bytes read is,
at most, equal to the length of b. Let k be the
number of bytes actually read; these bytes will be stored in elements
b[0] through b[k-1],
leaving elements b[k] through
b[b.length-1] unaffected.
The read(b) method for class InputStream
has the same effect as:
read(b, 0, b.length) read in class java.io.InputStreamb - the buffer into which the data is read.-1 is there is no more data because the end of
the stream has been reached.java.io.IOException - If the first byte cannot be read for any reason
other than the end of the file, if the input stream has been closed, or
if some other I/O error occurs.java.lang.NullPointerException - if b is null.InputStream.read(byte[], int, int)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.
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 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.
The read(b, off, 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 read(b, off, 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.
read in class java.io.InputStreamb - 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 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.java.lang.NullPointerException - If b is null.java.lang.IndexOutOfBoundsException - If off is negative,
len is negative, or len is greater than
b.length - offInputStream.read()