Class java.io.SequenceInputStream - JDK 5 Documentation v1.1.8, Java 2 SDK 英文文档

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Class java.io.SequenceInputStream

java.lang.Object
   |
   +----java.io.InputStream
           |
           +----java.io.SequenceInputStream

public class SequenceInputStream
extends InputStream

The sequence input stream class allows an application to combine several input streams serially and make them appear as if they were a single input stream. Each input stream is read from, in turn, until it reaches the end of the stream. The sequence input stream class then closes that stream and automatically switches to the next input stream.

SequenceInputStream(Enumeration): Constructs a new sequence input stream initialized to the specified enumeration of input streams.
SequenceInputStream(InputStream, InputStream): Constructs a new sequence input stream initialized to read first from the input stream s1, and then from the input stream s2.

available(): Returns the number of bytes available on the current stream.
close(): Closes this input stream and releases any system resources associated with the stream.
read(): Reads the next byte of data from this input stream.
read(byte[], int, int): Reads up to len bytes of data from this input stream into an array of bytes.

SequenceInputStream

 public SequenceInputStream(Enumeration e)

Constructs a new sequence input stream initialized to the specified enumeration of input streams. Each object in the enumeration must be an InputStream.

Parameters:: e - an enumeration of input streams.
See Also:: Enumeration

SequenceInputStream

 public SequenceInputStream(InputStream s1,
                            InputStream s2)

Constructs a new sequence input stream initialized to read first from the input stream s1, and then from the input stream s2.

Parameters:: s1 - the first input stream to read.; s2 - the second input stream to read.

available

 public int available() throws IOException

Returns the number of bytes available on the current stream.

Overrides:: available in class InputStream

read

 public int read() throws IOException

Reads the next byte of data from this input stream. The byte is returned as an 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.

The read method of SequenceInputStream 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.

Returns:: the next byte of data, or -1 if the end of the stream is reached.
Throws: IOException: if an I/O error occurs.
Overrides:: read in class InputStream

read

 public int read(byte buf[],
                 int pos,
                 int len) throws IOException

Reads up to len bytes of data from this input stream into an array of bytes. This method blocks until at least 1 byte of input is available. If the first argument is null, up to len bytes are read and discarded.

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.

Parameters:: b - the buffer into which the data is read.; off - the start offset of the data.; len - the maximum number of bytes read.
Throws: IOException: if an I/O error occurs.
Overrides:: read in class InputStream

close

 public void close() throws IOException

Closes this input stream and releases any system resources associated with the stream.

The close method of SequenceInputStream calls the close method of both the substream from which it is currently reading and the close method of all the substreams that it has not yet begun to read from.

Throws: IOException: if an I/O error occurs.
Overrides:: close in class InputStream

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