Package org.apache.commons.io.input

Class BoundedReader

java.lang.Object

java.io.Reader

org.apache.commons.io.input.BoundedReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class BoundedReader
extends Reader

A reader that imposes a limit to the number of characters that can be read from an underlying reader, returning EOF when this limit is reached, regardless of state of underlying reader.

One use case is to avoid overrunning the readAheadLimit supplied to Reader.mark(int), since reading too many characters removes the ability to do a successful reset.

Since:

2.5

Constructor Summary

Constructors

Constructor	Description
BoundedReader(Reader target, int maxCharsFromTargetReader)	Constructs a bounded reader

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the target
void	mark(int readAheadLimit)	marks the target stream
int	read()	Reads a single character
int	read(char[] cbuf, int off, int len)	Reads into an array
void	reset()	Resets the target to the latest mark,

Methods inherited from class java.io.Reader

markSupported, nullReader, read, read, ready, skip, transferTo

Methods inherited from class java.lang.Object

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

Constructor Detail

BoundedReader

public BoundedReader(Reader target,
                     int maxCharsFromTargetReader)
              throws IOException

Constructs a bounded reader

Parameters:

target - The target stream that will be used

maxCharsFromTargetReader - The maximum number of characters that can be read from target

Throws:

IOException - if mark fails

Method Detail

close

public void close()
           throws IOException

Closes the target

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Reader

Throws:

IOException - If an I/O error occurs while calling the underlying reader's close method

reset

public void reset()
           throws IOException

Resets the target to the latest mark,

Overrides:

reset in class Reader

Throws:

IOException - If an I/O error occurs while calling the underlying reader's reset method

See Also:

Reader.reset()

mark

public void mark(int readAheadLimit)
          throws IOException

marks the target stream

Overrides:

mark in class Reader

Parameters:

readAheadLimit - The number of characters that can be read while still retaining the ability to do #reset(). Note that this parameter is not validated with respect to maxCharsFromTargetReader. There is no way to pass past maxCharsFromTargetReader, even if this value is greater.

Throws:

IOException - If an I/O error occurs while calling the underlying reader's mark method

See Also:

Reader.mark(int)

read

public int read()
         throws IOException

Reads a single character

Overrides:

read in class Reader

Returns:

-1 on eof or the character read

Throws:

IOException - If an I/O error occurs while calling the underlying reader's read method

See Also:

Reader.read()

read

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

Reads into an array

Specified by:

read in class Reader

Parameters:

cbuf - The buffer to fill

off - The offset

len - The number of chars to read

Returns:

the number of chars read

Throws:

IOException - If an I/O error occurs while calling the underlying reader's read method

See Also:

Reader.read(char[], int, int)