info.bioinfweb.commons.io

Class LimitedReader

java.lang.Object

java.io.Reader

info.bioinfweb.commons.io.LimitedReader

All Implemented Interfaces:

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

public class LimitedReader
extends java.io.Reader

Guarantees that no more characters as specified are read from the decorated reader. It is though possible, that the decorated reader reads beyond the read limit from its underlying reader (e.g. if a BufferedReader is decorated).

The focus of this class is to make sure that not more characters than specified can be read from the underlying reader. It can e.g. be used to ensure that reading beyond the read ahead limit of a call of mark(int) is not possible.

Since:

2.0.0

Author:

Ben Stöver

See Also:

LimitedInputStream

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
LimitedReader(java.io.Reader decoratedReader, long limit) Creates a new instance of this class.

Method Summary

Modifier and Type	Method and Description
long	availableCharacters() The number of characters available, before the specified maximum number will have been read from the decorated reader.
void	close() Closes the decorated reader, if that is currently allowed.
long	getLimit() Returns the maximum number of characters that will be read from the decorated reader.
boolean	isAllowClose() Determines whether closing this reader shall currently be prevented.
boolean	isLimitReached() Checks whether the specified maximum number of characters has been read from the underlying reader.
void	mark(int readAheadLimit)
boolean	markSupported()
int	read(char[] buffer, int offset, int length)
boolean	ready()
void	reset()
void	setAllowClose(boolean allowClose) Allows to specify whether closing this reader shall currently be prevented.
long	skip(long n)

Methods inherited from class java.io.Reader

read, read, read

Methods inherited from class java.lang.Object

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

Constructor Detail

LimitedReader

public LimitedReader(java.io.Reader decoratedReader,
                     long limit)

Creates a new instance of this class.

Parameters:

decoratedReader - the reader to be decorated

limit - the maximum number of characters that shall be read from the decorated reader

Method Detail

getLimit

public long getLimit()

Returns the maximum number of characters that will be read from the decorated reader.

Returns:

the maximum number of characters to be read from the decorated reader

availableCharacters

public long availableCharacters()

The number of characters available, before the specified maximum number will have been read from the decorated reader. Note that the end of the input source (e.g. end of file) may possibly be reached before the specified character limit, which is not reflected by the return value of this method.

Returns:

the number of characters that could be read before the limit of this reader is reached

isLimitReached

public boolean isLimitReached()

Checks whether the specified maximum number of characters has been read from the underlying reader.

Returns:

true if the maximum number of characters was read

isAllowClose

public boolean isAllowClose()

Determines whether closing this reader shall currently be prevented. Calls of close() will throw an ClosingNotAllowedException in such cases.

Returns:

true, if closing this reader will currently be prevented or false otherwise

setAllowClose

public void setAllowClose(boolean allowClose)

Allows to specify whether closing this reader shall currently be prevented. Calls of close() will then throw an ClosingNotAllowedException.

Parameters:

allowClose - Specify true here, if closing shall be prevented from now on or false otherwise.

close

public void close()
           throws java.io.IOException

Closes the decorated reader, if that is currently allowed. Closing a previously closed reader 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:

ClosingNotAllowedException - if isAllowClose() currently returns true. (Calling this method, if the decorated reader was already closed will also throw this exception, if closing is currently not allowed.)

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

See Also:

setAllowClose(boolean), Reader.close()

read

public int read(char[] buffer,
                int offset,
                int length)
         throws java.io.IOException

Specified by:

read in class java.io.Reader

Throws:

java.io.IOException

skip

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

Overrides:

skip in class java.io.Reader

Throws:

java.io.IOException

mark

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

Overrides:

mark in class java.io.Reader

Throws:

java.io.IOException

markSupported

public boolean markSupported()

Overrides:

markSupported in class java.io.Reader

ready

public boolean ready()
              throws java.io.IOException

Overrides:

ready in class java.io.Reader

Throws:

java.io.IOException

reset

public void reset()
           throws java.io.IOException

Overrides:

reset in class java.io.Reader

Throws:

java.io.IOException