public class SequenceInputStream extends InputStream
SequenceInputStream
represents the logical concatenation of other input streams. It starts out with an
ordered collection of input streams and reads from the first one until end of file is reached, whereupon it reads
from the second one, and so on, until end of file is reached on the last of the contained input streams.Constructor and Description |
---|
SequenceInputStream(Enumeration<? extends InputStream> e)
Initializes a newly created
SequenceInputStream by remembering the argument, which must be an
Enumeration that produces objects whose run-time type is InputStream . |
SequenceInputStream(InputStream s1,
InputStream s2)
Initializes a newly created
SequenceInputStream by remembering the two arguments, which will be read
in order, first s1 and then s2 , to provide the bytes to be read from this
SequenceInputStream . |
Modifier and Type | Method and Description |
---|---|
int |
available()
Returns an estimate of the number of bytes that can be read (or skipped over) from the current underlying input
stream without blocking by the next invocation of a method for the current underlying input stream.
|
void |
close()
Closes this input stream and releases any system resources associated with the 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. |
mark, markSupported, read, reset, skip
public SequenceInputStream(Enumeration<? extends InputStream> e)
SequenceInputStream
by remembering the argument, which must be an
Enumeration
that produces objects whose run-time type is InputStream
. The input streams
that are produced by the enumeration will be read, in order, to provide the bytes to be read from this
SequenceInputStream
. After each input stream from the enumeration is exhausted, it is closed by
calling its close
method.e
- an enumeration of input streams.Enumeration
public SequenceInputStream(InputStream s1, InputStream s2)
SequenceInputStream
by remembering the two arguments, which will be read
in order, first s1
and then s2
, to provide the bytes to be read from this
SequenceInputStream
.s1
- the first input stream to read.s2
- the second input stream to read.public int available() throws IOException
This method simply calls available
of the current underlying input stream and returns the result.
available
in class InputStream
0
if this input stream has been closed by invoking its
close()
methodIOException
- if an I/O error occurs.public void close() throws IOException
SequenceInputStream
cannot perform input operations and cannot be reopened.
If this stream was created from an enumeration, all remaining elements are requested from the enumeration and
closed before the close
method returns.
close
in interface Closeable
close
in interface AutoCloseable
close
in class InputStream
IOException
- if an I/O error occurs.public int read() throws 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.
This method tries to read one character from the current substream. If it reaches the end of the stream, it calls
the close
method of the current substream and begins reading from the next substream.
read
in class InputStream
-1
if the end of the stream is reached.IOException
- if an I/O error occurs.public int read(@Nullable byte[] b, int off, int len) throws IOException
len
bytes of data from this input stream into an array of bytes. If len
is
not zero, the method blocks until at least 1 byte of input is available; otherwise, no bytes are read and
0
is returned.
The read
method of SequenceInputStream
tries to read the data from the current
substream. If it fails to read any characters because the substream has reached the end of the stream, it calls
the close
method of the current substream and begins reading from the next substream.
read
in class InputStream
b
- 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 read.NullPointerException
- If b
is null
.IndexOutOfBoundsException
- If off
is negative, len
is negative, or len
is greater than
b.length - off
IOException
- if an I/O error occurs.InputStream.read()