org.apache.commons.io.input
public class NullInputStream extends InputStream
This implementation provides a light weight object for testing with an InputStream where the contents don't matter.
One use case would be for testing the handling of large InputStream as it can emulate that scenario without the overhead of actually processing large numbers of bytes - significantly speeding up test execution times.
This implementation returns zero from the method that
reads a byte and leaves the array unchanged in the read
methods that are passed a byte array.
If alternative data is required the processByte()
and
processBytes()
methods can be implemented to generate
data, for example:
public class TestInputStream extends NullInputStream { public TestInputStream(int size) { super(size); } protected int processByte() { return ... // return required value here } protected void processBytes(byte[] bytes, int offset, int length) { for (int i = offset; i < length; i++) { bytes[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 | |
---|---|
NullInputStream(long size)
Create an InputStream that emulates a specified size
which supports marking and does not throw EOFException.
| |
NullInputStream(long size, boolean markSupported, boolean throwEofException)
Create an InputStream that emulates a specified
size with option settings.
|
Method Summary | |
---|---|
int | available()
Return the number of bytes that can be read.
|
void | close()
Close this input stream - 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 InputStream emulates.
|
void | mark(int readlimit)
Mark the current position.
|
boolean | markSupported()
Indicates whether mark is supported.
|
protected int | processByte()
Return a byte value for the read() method.
|
protected void | processBytes(byte[] bytes, int offset, int length)
Process the bytes for the read(byte[], offset, length)
method.
|
int | read()
Read a byte.
|
int | read(byte[] bytes)
Read some bytes into the specified array.
|
int | read(byte[] bytes, int offset, int length)
Read the specified number bytes into an array.
|
void | reset()
Reset the stream to the point when mark was last called.
|
long | skip(long numberOfBytes)
Skip a specified number of bytes.
|
Parameters: size The size of the input stream to emulate.
Parameters: size The size of the input stream 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.
Returns: The number of bytes that can be read.
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 input stream to emulate.
Parameters: readlimit The number of bytes 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(byte[], offset, length)
method.
This implementation leaves the byte array unchanged.
Parameters: bytes The byte array offset The offset to start at. length The number of bytes.
Returns: Either The byte value returned by processByte()
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: bytes The byte array to read into
Returns: The number of bytes 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: bytes The byte array to read into. offset The offset to start reading bytes into. length The number of bytes to read.
Returns: The number of bytes 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: numberOfBytes The number of bytes to skip.
Returns: The number of bytes 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.