Package org.apache.commons.io.input

Class BoundedReader

java.lang.Object

java.io.Reader

java.io.FilterReader

org.apache.commons.io.input.ProxyReader

org.apache.commons.io.input.BoundedReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class BoundedReader
extends ProxyReader

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

Field Summary

Fields inherited from class java.io.FilterReader

in

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
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,
long	skip(long n)	Invokes the delegate's skip(long) method.

Methods inherited from class org.apache.commons.io.input.ProxyReader

afterRead, beforeRead, close, handleIOException, markSupported, read, read, ready, setReference, unwrap

Methods inherited from class java.lang.Object

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

Constructor Details

BoundedReader

public BoundedReader(Reader target,
 int maxCharsFromTargetReader)

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.

Method Details

mark

public void mark(int readAheadLimit)
          throws IOException

marks the target stream

Overrides:

mark in class ProxyReader

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 ProxyReader

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

Overrides:

read in class ProxyReader

Parameters:

cbuf - The buffer to fill.

off - The offset.

len - The number of chars to read.

Returns:

the number of chars read.

Throws:

NullPointerException - if the buffer is null.

IndexOutOfBoundsException - if off or len are negative, or if off + len is greater than cbuf.length.

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

See Also:

• Reader.read(char[], int, int)

reset

public void reset()
           throws IOException

Resets the target to the latest mark,

Overrides:

reset in class ProxyReader

Throws:

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

See Also:

• Reader.reset()

skip

public long skip(long n)
          throws IOException

Description copied from class: ProxyReader

Invokes the delegate's skip(long) method.

Overrides:

skip in class ProxyReader

Parameters:

n - the number of bytes to skip.

Returns:

the number of bytes to skipped or EOF if the end of stream.

Throws:

IOException - if an I/O error occurs.