ca.gorman.util.scan.spi
Class AbstractReaderBuffer

java.lang.Object
  ca.gorman.util.scan.spi.AbstractReaderBuffer

All Implemented Interfaces:

Expandable, InputControl, CharSequence

public abstract class AbstractReaderBuffer
extends Object
implements CharSequence, InputControl

Input buffer factory to support a ScanBuffer implementation on a java.io.Reader.

The default implementation is expandable to hold character sequences of arbitrary length, within the limits imposed by the availability of free memory.

Nested Class Summary

Nested classes/interfaces inherited from interface ca.gorman.util.scan.InputControl

InputControl.Default

Constructor Summary

protected

AbstractReaderBuffer(Reader reader)

Method Summary

char	charAt(int index)
int	discard(int index) Discard a leading prefix of characters from the buffer.
boolean	expand() Increase the amount of data in the buffer, if the buffer supports expansion.
int	fill() Make more characters available in a buffer with free space.
int	length()
static AbstractReaderBuffer	newInstance(Reader reader)
CharSequence	subSequence(int start, int end)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractReaderBuffer

protected AbstractReaderBuffer(Reader reader)
                        throws IOException

Throws:

IOException

Method Detail

newInstance

public static AbstractReaderBuffer newInstance(Reader reader)
                                        throws IOException

Throws:

IOException

charAt

public char charAt(int index)

Specified by:

charAt in interface CharSequence

length

public int length()

Specified by:

length in interface CharSequence

subSequence

public CharSequence subSequence(int start,
                                int end)

Specified by:

subSequence in interface CharSequence

toString

public String toString()

Specified by:

toString in interface CharSequence

Overrides:

toString in class Object

discard

public int discard(int index)

Description copied from interface: InputControl

Discard a leading prefix of characters from the buffer.

Specified by:

discard in interface InputControl

Parameters:

index - The number of characters to be discarded

Returns:

The number (from zero to the number requested) of characters discarded

fill

public int fill()
         throws IOException

Description copied from interface: InputControl

Make more characters available in a buffer with free space.

Specified by:

fill in interface InputControl

Returns:

the number (possibly zero) of additional characters made available, or a negative number to indicate that additional chaacters will never be available.

Throws:

IOException

expand

public boolean expand()
               throws IOException

Description copied from interface: Expandable

Increase the amount of data in the buffer, if the buffer supports expansion.

Expansion is not guaranteed, because the buffer may not support expansion or because the current state of the buffer (or its data source) may not permit expansion.

A successful expansion of a full buffer will increase the memory used by the buffer. A buffer with free space may simply add more data to the free space instead of acquiring and filling additional memory.

Specified by:

expand in interface Expandable

Returns:

true if more data has been made available in the buffer

Throws:

IOException