com.Ostermiller.util

Class ConcatReader

java.lang.Object

java.io.Reader

com.Ostermiller.util.ConcatReader

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable

public class ConcatReader
extends java.io.Reader

A reader which reads sequentially from multiple sources. More information about this class is available from ostermiller.org.

Since:

ostermillerutils 1.04.00

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
ConcatReader() Create a new reader that can dynamically accept new sources.
ConcatReader(java.io.Reader in) Create a new reader with one source.
ConcatReader(java.io.Reader[] in) Create a new reader with an arbitrary number of sources.
ConcatReader(java.io.Reader in1, java.io.Reader in2) Create a new reader with two sources.

Method Summary

Modifier and Type	Method and Description
void	addReader(java.io.Reader in) Add the given reader to the queue of readers from which to concatenate data.
void	addReaders(java.io.Reader[] in) Add the given reader to the queue of readers from which to concatenate data.
void	close() Close the stream and any underlying streams.
void	lastReaderAdded() Causes the addReader method to throw IllegalStateException and read() methods to return -1 (end of stream) when there is no more available data.
void	mark(int readlimit) Mark not supported.
boolean	markSupported() Mark not supported.
int	read() Read a single character.
int	read(char[] cbuf) Read characters into an array.
int	read(char[] cbuf, int off, int len) Read characters into a portion of an array.
boolean	ready() Tell whether this stream is ready to be read.
void	reset() Reset not supported.
long	skip(long n) Skip characters.

Methods inherited from class java.io.Reader

read

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcatReader

public ConcatReader()

Create a new reader that can dynamically accept new sources.

New sources should be added using the addReader() method. When all sources have been added the lastReaderAdded() should be called so that read methods can return -1 (end of stream).

Adding new sources may by interleaved with read calls.

Since:

ostermillerutils 1.04.01

ConcatReader

public ConcatReader(java.io.Reader in)

Create a new reader with one source.

When using this constructor, more readers cannot be added later, and calling addReader() will throw an illegal state Exception.

Parameters:

in - reader to use as a source.

Throws:

java.lang.NullPointerException - if in is null

Since:

ostermillerutils 1.04.00

ConcatReader

public ConcatReader(java.io.Reader in1,
                    java.io.Reader in2)

Create a new reader with two sources.

When using this constructor, more readers cannot be added later, and calling addReader() will throw an illegal state Exception.

Parameters:

in1 - first reader to use as a source.

in2 - second reader to use as a source.

Throws:

java.lang.NullPointerException - if either source is null.

Since:

ostermillerutils 1.04.00

ConcatReader

public ConcatReader(java.io.Reader[] in)

Create a new reader with an arbitrary number of sources.

When using this constructor, more readers cannot be added later, and calling addReader() will throw an illegal state Exception.

Parameters:

in - readers to use as a sources.

Throws:

java.lang.NullPointerException - if the input array on any element is null.

Since:

ostermillerutils 1.04.00

Method Detail

lastReaderAdded

public void lastReaderAdded()

Causes the addReader method to throw IllegalStateException and read() methods to return -1 (end of stream) when there is no more available data.

Calling this method when this class is no longer accepting more readers has no effect.

Since:

ostermillerutils 1.04.01

addReader

public void addReader(java.io.Reader in)

Add the given reader to the queue of readers from which to concatenate data.

Parameters:

in - Reader to add to the concatenation.

Throws:

java.lang.IllegalStateException - if more readers can't be added because lastReaderAdded() has been called, close() has been called, or a constructor with reader parameters was used.

Since:

ostermillerutils 1.04.01

addReaders

public void addReaders(java.io.Reader[] in)

Add the given reader to the queue of readers from which to concatenate data.

Parameters:

in - Reader to add to the concatenation.

Throws:

java.lang.IllegalStateException - if more readers can't be added because lastReaderAdded() has been called, close() has been called, or a constructor with reader parameters was used.

java.lang.NullPointerException - the array of readers, or any of the contents is null.

Since:

ostermillerutils 1.04.01

read

public int read()
         throws java.io.IOException

Read a single character. This method will block until a character is available, an I/O error occurs, or the end of all underlying streams are reached.

If this class in not done accepting readers and the end of the last known stream is reached, this method will block forever unless another thread adds a reader or interrupts.

Overrides:

read in class java.io.Reader

Returns:

The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached

Throws:

java.io.IOException - - If an I/O error occurs

Since:

ostermillerutils 1.04.00

read

public int read(char[] cbuf)
         throws java.io.IOException

Read characters into an array. This method will block until some input is available, an I/O error occurs, or the end of all underlying streams are reached.

If this class in not done accepting readers and the end of the last known stream is reached, this method will block forever unless another thread adds a reader or interrupts.

Overrides:

read in class java.io.Reader

Parameters:

cbuf - - Destination buffer

Returns:

The number of characters read, or -1 if the end of the stream has been reached

Throws:

java.io.IOException - - If an I/O error occurs

java.lang.NullPointerException - - If the buffer is null.

Since:

ostermillerutils 1.04.00

read

public int read(char[] cbuf,
                int off,
                int len)
         throws java.io.IOException

Read characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of all underlying streams are reached.

If this class in not done accepting readers and the end of the last known stream is reached, this method will block forever unless another thread adds a reader or interrupts.

Specified by:

read in class java.io.Reader

Parameters:

cbuf - Destination buffer

off - Offset at which to start storing characters

len - Maximum number of characters to read

Returns:

The number of characters read, or -1 if the end of the stream has been reached

Throws:

java.io.IOException - - If an I/O error occurs

java.lang.NullPointerException - - If the buffer is null.

java.lang.IndexOutOfBoundsException - - if length or offset are not possible.

Since:

ostermillerutils 1.04.00

skip

public long skip(long n)
          throws java.io.IOException

Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

If this class in not done accepting readers and the end of the last known stream is reached, this method will block forever unless another thread adds a reader or interrupts.

Overrides:

skip in class java.io.Reader

Parameters:

n - the number of characters to skip

Returns:

The number of characters actually skipped

Throws:

java.lang.IllegalArgumentException - If n is negative.

java.io.IOException - If an I/O error occurs

Since:

ostermillerutils 1.04.00

ready

public boolean ready()
              throws java.io.IOException

Tell whether this stream is ready to be read.

Overrides:

ready in class java.io.Reader

Returns:

True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

Throws:

java.io.IOException - If an I/O error occurs

Since:

ostermillerutils 1.04.00

close

public void close()
           throws java.io.IOException

Close the stream and any underlying streams. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in class java.io.Reader

Throws:

java.io.IOException - If an I/O error occurs

Since:

ostermillerutils 1.04.00

mark

public void mark(int readlimit)
          throws java.io.IOException

Mark not supported.

Overrides:

mark in class java.io.Reader

Throws:

java.io.IOException - because mark is not supported.

Since:

ostermillerutils 1.04.00

reset

public void reset()
           throws java.io.IOException

Reset not supported.

Overrides:

reset in class java.io.Reader

Throws:

java.io.IOException - because reset is not supported.

Since:

ostermillerutils 1.04.00

markSupported

public boolean markSupported()

Mark not supported.

Overrides:

markSupported in class java.io.Reader

Returns:

false

Since:

ostermillerutils 1.04.00