net.sf.kdgcommons.io

Class GeneratedInputStream

java.lang.Object

java.io.InputStream

net.sf.kdgcommons.io.GeneratedInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public abstract class GeneratedInputStream
extends InputStream

An InputStream that calls a method to generate blocks of data. This can be used to replace a pipe in many situations where you can't spin up a new thread. It's also useful for testing.

To use, implement nextBuffer(). Each time this method is called, it should return an arbitrary-size byte[] containing the next chunk of data. At EOF, it returns null.

Constructor Summary

Constructors

Constructor and Description
GeneratedInputStream()

Method Summary

Modifier and Type	Method and Description
int	available() Returns the number of bytes available in the current buffer — assumes that a call to nextBuffer() will block.
void	close() By default, closing the stream simply sets a flag such that all subsequent reads will throw.
void	mark(int readlimit) By default, this method does nothing.
boolean	markSupported() By default this method returns false.
protected abstract byte[]	nextBuffer() Returns the next buffer of generated data, null when there's no more data.
int	read()
int	read(byte[] b) Attempts to completely fill the passed buffer, calling nextBuffer() until it is either full or EOF is reached.
int	read(byte[] b, int off, int len)
void	reset() By default this method throws IOException.
long	skip(long n) This method calls read() until either the requisite number of bytes have been read, or EOF is reached.

Methods inherited from class java.lang.Object

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

Constructor Detail

GeneratedInputStream

public GeneratedInputStream()

Method Detail

available

public int available()
              throws IOException

Returns the number of bytes available in the current buffer — assumes that a call to nextBuffer() will block.

Overrides:

available in class InputStream

Throws:

IOException

close

public void close()
           throws IOException

By default, closing the stream simply sets a flag such that all subsequent reads will throw. Subclasses may chose to override.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

mark

public void mark(int readlimit)

By default, this method does nothing. Subclasses may override.

Overrides:

mark in class InputStream

markSupported

public boolean markSupported()

By default this method returns false. Subclasses may override.

Overrides:

markSupported in class InputStream

reset

public void reset()
           throws IOException

By default this method throws IOException. Subclasses may override.

Overrides:

reset in class InputStream

Throws:

IOException

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Overrides:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b)
         throws IOException

Attempts to completely fill the passed buffer, calling nextBuffer() until it is either full or EOF is reached. Note that this differs from a "normal" stream, which makes a single attempt to read the underlying data.

Overrides:

read in class InputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

This method calls read() until either the requisite number of bytes have been read, or EOF is reached.

Overrides:

skip in class InputStream

Throws:

IOException

nextBuffer

protected abstract byte[] nextBuffer()
                              throws IOException

Returns the next buffer of generated data, null when there's no more data. Buffers may be any size.

Throws:

IOException