jsimple.io

Class SequenceInputStream

java.lang.Object

jsimple.lang.AutoCloseable

jsimple.io.InputStream

jsimple.io.SequenceInputStream

All Implemented Interfaces:

java.lang.AutoCloseable

public class SequenceInputStream
extends InputStream

This class was based on, and modified from, the Apache Harmony java.io.SequenceInputStream class. Unlike the standard Java SequenceInputStream class, uses as Iterator instead of the legacy JDK 1.0 Enumeration class to hold the list of InputStreams. That, plus of course using JSimple InputStreams, were the only changes. Concatenates two or more existing InputStreams. Reads are taken from the first stream until it ends, then the next stream is used, until the last stream returns end of file.

Constructor Summary

Constructors

Constructor and Description
SequenceInputStream(ArrayList<InputStream> inputStreams) Constructs a new SequenceInputStream using the elements returned from inputStreams as the stream sequence.
SequenceInputStream(InputStream s1, InputStream s2) Constructs a new SequenceInputStream using the two streams s1 and s2 as the sequence of streams to read from.

Method Summary

Modifier and Type	Method and Description
void	close() Closes all streams in this sequence of input stream.
int	read() Reads a single byte from this sequence of input streams and returns it as an integer in the range from 0 to 255.
int	read(byte[] buffer, int offset, int count) Reads at most count bytes from this sequence of input streams and stores them in the byte array buffer starting at offset.

Methods inherited from class jsimple.io.InputStream

copyTo, copyToByteArray, finalize, read, readFully, readFully

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SequenceInputStream

public SequenceInputStream(InputStream s1,
                           InputStream s2)

Constructs a new SequenceInputStream using the two streams s1 and s2 as the sequence of streams to read from.

Parameters:

s1 - the first stream to get bytes from.

s2 - the second stream to get bytes from.

SequenceInputStream

public SequenceInputStream(ArrayList<InputStream> inputStreams)

Constructs a new SequenceInputStream using the elements returned from inputStreams as the stream sequence.

Parameters:

inputStreams - ArrayList of InputStreams to get bytes from

Method Detail

close

public void close()

Closes all streams in this sequence of input stream.

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in class InputStream

read

public int read()

Reads a single byte from this sequence of input streams and returns it as an integer in the range from 0 to 255. It tries to read from the current stream first; if the end of this stream has been reached, it reads from the next one. Blocks until one byte has been read, the end of the last input stream in the sequence has been reached, or an exception is thrown.

Specified by:

read in class InputStream

Returns:

the byte read or -1 if either the end of the last stream in the sequence has been reached or this input stream sequence is closed.

read

public int read(byte[] buffer,
                int offset,
                int count)

Reads at most count bytes from this sequence of input streams and stores them in the byte array buffer starting at offset. Blocks only until at least 1 byte has been read, the end of the stream has been reached, or an exception is thrown.

This SequenceInputStream shows the same behavior as other InputStreams. To do this it will read only as many bytes as a call to read on the current substream returns. If that call does not return as many bytes as requested by count, it will not retry to read more on its own because subsequent reads might block. This would violate the rule that it will only block until at least one byte has been read.

If a substream has already reached the end when this call is made, it will close that substream and start with the next one. If there are no more substreams it will return -1.

Specified by:

read in class InputStream

Parameters:

buffer - the array in which to store the bytes read.

offset - the initial position in buffer to store the bytes read from this stream.

count - the maximum number of bytes to store in buffer.

Returns:

the number of bytes actually read; -1 if this sequence of streams is closed or if the end of the last stream in the sequence has been reached.

Throws:

java.lang.IndexOutOfBoundsException - if offset < 0 or count < 0, or if offset + count is greater than the size of buffer.