Package com.helger.commons.io.stream

Class NonBlockingPushbackReader

java.lang.Object

java.io.Reader

java.io.FilterReader

com.helger.commons.io.stream.NonBlockingPushbackReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class NonBlockingPushbackReader
extends FilterReader

A non-synchronized copy of the class PushbackReader.

Author:

Philip Helger

See Also:

PushbackReader

Field Summary

Fields inherited from class java.io.FilterReader

in

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor	Description
NonBlockingPushbackReader(Reader aReader)	Creates a new pushback reader with a one-character pushback buffer.
NonBlockingPushbackReader(Reader aReader, int nSize)	Creates a new pushback reader with a pushback buffer of the given size.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the stream and releases any system resources associated with it.
int	getUnreadCount()
boolean	hasUnreadChars()
void	mark(int readAheadLimit)	Marks the present position in the stream.
boolean	markSupported()	Tells whether this stream supports the mark() operation, which it does not.
int	read()	Reads a single character.
int	read(char[] aBuf, int nOfs, int nLen)	Reads characters into a portion of an array.
boolean	ready()	Tells whether this stream is ready to be read.
void	reset()	Resets the stream.
long	skip(long nSkip)	Skips characters.
void	unread(char[] aBuf)	Pushes back an array of characters by copying it to the front of the pushback buffer.
void	unread(char[] aBuf, int nOfs, int nLen)	Pushes back a portion of an array of characters by copying it to the front of the pushback buffer.
void	unread(int c)	Pushes back a single character by copying it to the front of the pushback buffer.

Methods inherited from class java.io.Reader

nullReader, read, read, transferTo

Methods inherited from class java.lang.Object

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

Constructor Detail

NonBlockingPushbackReader

public NonBlockingPushbackReader(@Nonnull
                                 Reader aReader,
                                 @Nonnegative
                                 int nSize)

Creates a new pushback reader with a pushback buffer of the given size.

Parameters:

aReader - The reader from which characters will be read

nSize - The size of the pushback buffer

Throws:

IllegalArgumentException - if size is ≤ 0

NonBlockingPushbackReader

public NonBlockingPushbackReader(@Nonnull
                                 Reader aReader)

Creates a new pushback reader with a one-character pushback buffer.

Parameters:

aReader - The reader from which characters will be read

Method Detail

getUnreadCount

@Nonnegative
public int getUnreadCount()

Returns:

The number of chars currently in the "unread" buffer.

hasUnreadChars

public boolean hasUnreadChars()

Returns:

true if at least one "unread" char is present.

read

public int read()
         throws IOException

Reads a single character.

Overrides:

read in class FilterReader

Returns:

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

Throws:

IOException - If an I/O error occurs

read

public int read(@Nonnull
                char[] aBuf,
                @Nonnegative
                int nOfs,
                @Nonnegative
                int nLen)
         throws IOException

Reads characters into a portion of an array.

Overrides:

read in class FilterReader

Parameters:

aBuf - Destination buffer

nOfs - Offset at which to start writing characters

nLen - Maximum number of characters to read

Returns:

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

Throws:

IOException - If an I/O error occurs

unread

public void unread(int c)
            throws IOException

Pushes back a single character by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value (char)c.

Parameters:

c - The int value representing a character to be pushed back

Throws:

IOException - If the pushback buffer is full, or if some other I/O error occurs

unread

public void unread(@Nonnull
                   char[] aBuf,
                   @Nonnegative
                   int nOfs,
                   @Nonnegative
                   int nLen)
            throws IOException

Pushes back a portion of an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[off], the character after that will have the value cbuf[off+1], and so forth.

Parameters:

aBuf - Character array

nOfs - Offset of first character to push back

nLen - Number of characters to push back

Throws:

IOException - If there is insufficient room in the pushback buffer, or if some other I/O error occurs

unread

public void unread(@Nonnull
                   char[] aBuf)
            throws IOException

Pushes back an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[0], the character after that will have the value cbuf[1], and so forth.

Parameters:

aBuf - Character array to push back

Throws:

IOException - If there is insufficient room in the pushback buffer, or if some other I/O error occurs

ready

public boolean ready()
              throws IOException

Tells whether this stream is ready to be read.

Overrides:

ready in class FilterReader

Throws:

IOException - If an I/O error occurs

mark

public void mark(int readAheadLimit)
          throws IOException

Marks the present position in the stream. The mark for class PushbackReader always throws an exception.

Overrides:

mark in class FilterReader

Throws:

IOException - Always, since mark is not supported

reset

public void reset()
           throws IOException

Resets the stream. The reset method of PushbackReader always throws an exception.

Overrides:

reset in class FilterReader

Throws:

IOException - Always, since reset is not supported

markSupported

public boolean markSupported()

Tells whether this stream supports the mark() operation, which it does not.

Overrides:

markSupported in class FilterReader

close

public void close()
           throws IOException

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), unread(), ready(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterReader

Throws:

IOException - If an I/O error occurs

skip

public long skip(long nSkip)
          throws IOException

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

Overrides:

skip in class FilterReader

Parameters:

nSkip - The number of characters to skip. Must be ≥ 0.

Returns:

The number of characters actually skipped

Throws:

IllegalArgumentException - If n is negative.

IOException - If an I/O error occurs