org.apache.commons.io.input
public class NullReader extends Reader
This implementation provides a light weight object for testing with an Reader where the contents don't matter.
One use case would be for testing the handling of large Reader as it can emulate that scenario without the overhead of actually processing large numbers of characters - significantly speeding up test execution times.
This implementation returns a space from the method that
reads a character and leaves the array unchanged in the read
methods that are passed a character array.
If alternative data is required the processChar()
and
processChars()
methods can be implemented to generate
data, for example:
public class TestReader extends NullReader { public TestReader(int size) { super(size); } protected char processChar() { return ... // return required value here } protected void processChars(char[] chars, int offset, int length) { for (int i = offset; i < length; i++) { chars[i] = ... // set array value here } } }
Since: Commons IO 1.3
Version: $Revision: 463529 $
Field Summary | |
---|---|
boolean | eof |
long | mark |
boolean | markSupported |
long | position |
long | readlimit |
long | size |
boolean | throwEofException |
Constructor Summary | |
---|---|
NullReader(long size)
Create a Reader that emulates a specified size
which supports marking and does not throw EOFException.
| |
NullReader(long size, boolean markSupported, boolean throwEofException)
Create a Reader that emulates a specified
size with option settings.
|
Method Summary | |
---|---|
void | close()
Close this Reader - resets the internal state to
the initial values.
|
int | doEndOfFile()
Handle End of File.
|
long | getPosition()
Return the current position.
|
long | getSize()
Return the size this Reader emulates.
|
void | mark(int readlimit)
Mark the current position.
|
boolean | markSupported()
Indicates whether mark is supported.
|
protected int | processChar()
Return a character value for the read() method.
|
protected void | processChars(char[] chars, int offset, int length)
Process the characters for the read(char[], offset, length)
method.
|
int | read()
Read a character.
|
int | read(char[] chars)
Read some characters into the specified array.
|
int | read(char[] chars, int offset, int length)
Read the specified number characters into an array.
|
void | reset()
Reset the stream to the point when mark was last called.
|
long | skip(long numberOfChars)
Skip a specified number of characters.
|
Parameters: size The size of the reader to emulate.
Parameters: size The size of the reader to emulate. markSupported Whether this instance will support
the mark()
functionality. throwEofException Whether this implementation
will throw an EOFException or return -1 when the
end of file is reached.
Throws: IOException If an error occurs.
Returns: -1
if throwEofException
is
set to false
Throws: EOFException if throwEofException
is set
to true
.
Returns: the current position.
Returns: The size of the reader to emulate.
Parameters: readlimit The number of characters before this marked position is invalid.
Throws: UnsupportedOperationException if mark is not supported.
Returns: Whether mark is supported or not.
read()
method.
This implementation returns zero.
Returns: This implementation always returns zero.
read(char[], offset, length)
method.
This implementation leaves the character array unchanged.
Parameters: chars The character array offset The offset to start at. length The number of characters.
Returns: Either The character value returned by processChar()
or -1
if the end of file has been reached and
throwEofException
is set to false
.
Throws: EOFException if the end of file is reached and
throwEofException
is set to true
. IOException if trying to read past the end of file.
Parameters: chars The character array to read into
Returns: The number of characters read or -1
if the end of file has been reached and
throwEofException
is set to false
.
Throws: EOFException if the end of file is reached and
throwEofException
is set to true
. IOException if trying to read past the end of file.
Parameters: chars The character array to read into. offset The offset to start reading characters into. length The number of characters to read.
Returns: The number of characters read or -1
if the end of file has been reached and
throwEofException
is set to false
.
Throws: EOFException if the end of file is reached and
throwEofException
is set to true
. IOException if trying to read past the end of file.
Throws: UnsupportedOperationException if mark is not supported. IOException If no position has been marked or the read limit has been exceed since the last position was marked.
Parameters: numberOfChars The number of characters to skip.
Returns: The number of characters skipped or -1
if the end of file has been reached and
throwEofException
is set to false
.
Throws: EOFException if the end of file is reached and
throwEofException
is set to true
. IOException if trying to read past the end of file.