org.apache.commons.io.input
Class NullInputStream
InputStream
org.apache.commons.io.input.NullInputStream
public class NullInputStream
extends InputStream
A functional, light weight
InputStream
that emulates
a stream of a specified size.
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 <32length; i++) {
bytes[i] = ... // set array value here
}
}
}
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.
|
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.
|
private 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.
|
markSupported
private boolean markSupported
position
private long position
readlimit
private long readlimit
throwEofException
private boolean throwEofException
NullInputStream
public NullInputStream(long size)
Create an InputStream
that emulates a specified size
which supports marking and does not throw EOFException.
size
- The size of the input stream to emulate.
NullInputStream
public NullInputStream(long size,
boolean markSupported,
boolean throwEofException)
Create an InputStream
that emulates a specified
size with option settings.
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.
available
public int available()
Return the number of bytes that can be read.
- The number of bytes that can be read.
close
public void close()
throws IOException
Close this input stream - resets the internal state to
the initial values.
doEndOfFile
private int doEndOfFile()
throws EOFException
Handle End of File.
-1
if throwEofException
is
set to false
getPosition
public long getPosition()
Return the current position.
getSize
public long getSize()
Return the size this InputStream
emulates.
- The size of the input stream to emulate.
mark
public void mark(int readlimit)
Mark the current position.
readlimit
- The number of bytes before this marked position
is invalid.
markSupported
public boolean markSupported()
Indicates whether mark is supported.
- Whether mark is supported or not.
processByte
protected int processByte()
Return a byte value for the
read()
method.
This implementation returns zero.
- This implementation always returns zero.
processBytes
protected void processBytes(byte[] bytes,
int offset,
int length)
Process the bytes for the
read(byte[], offset, length)
method.
This implementation leaves the byte array unchanged.
bytes
- The byte arrayoffset
- The offset to start at.length
- The number of bytes.
read
public int read()
throws IOException
Read a byte.
- Either The byte value returned by
processByte()
or -1
if the end of file has been reached and
throwEofException
is set to false
.
read
public int read(byte[] bytes)
throws IOException
Read some bytes into the specified array.
bytes
- The byte array to read into
- The number of bytes read or
-1
if the end of file has been reached and
throwEofException
is set to false
.
read
public int read(byte[] bytes,
int offset,
int length)
throws IOException
Read the specified number bytes into an array.
bytes
- The byte array to read into.offset
- The offset to start reading bytes into.length
- The number of bytes to read.
- The number of bytes read or
-1
if the end of file has been reached and
throwEofException
is set to false
.
reset
public void reset()
throws IOException
Reset the stream to the point when mark was last called.
skip
public long skip(long numberOfBytes)
throws IOException
Skip a specified number of bytes.
numberOfBytes
- The number of bytes to skip.
- The number of bytes skipped or
-1
if the end of file has been reached and
throwEofException
is set to false
.
Copyright (c) 2002-2009 Apache Software Foundation