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java.lang.Objectjava.io.Reader
org.apache.commons.io.input.NullReader
public class NullReader
A functional, light weight Reader that emulates
a reader of a specified size.
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
}
}
}
| Field Summary |
|---|
| Fields inherited from class java.io.Reader |
|---|
lock |
| 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. |
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. |
| Methods inherited from class java.io.Reader |
|---|
read, ready |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
public NullReader(long size)
Reader that emulates a specified size
which supports marking and does not throw EOFException.
size - The size of the reader to emulate.
public NullReader(long size,
boolean markSupported,
boolean throwEofException)
Reader that emulates a specified
size with option settings.
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.| Method Detail |
|---|
public long getPosition()
public long getSize()
Reader emulates.
public void close()
throws IOException
close in interface Closeableclose in class ReaderIOException - If an error occurs.public void mark(int readlimit)
mark in class Readerreadlimit - The number of characters before this marked position
is invalid.
UnsupportedOperationException - if mark is not supported.public boolean markSupported()
markSupported in class Reader
public int read()
throws IOException
read in class ReaderprocessChar()
or -1 if the end of file has been reached and
throwEofException is set to false.
EOFException - if the end of file is reached and
throwEofException is set to true.
IOException - if trying to read past the end of file.
public int read(char[] chars)
throws IOException
read in class Readerchars - The character array to read into
-1
if the end of file has been reached and
throwEofException is set to false.
EOFException - if the end of file is reached and
throwEofException is set to true.
IOException - if trying to read past the end of file.
public int read(char[] chars,
int offset,
int length)
throws IOException
read in class Readerchars - The character array to read into.offset - The offset to start reading characters into.length - The number of characters to read.
-1
if the end of file has been reached and
throwEofException is set to false.
EOFException - if the end of file is reached and
throwEofException is set to true.
IOException - if trying to read past the end of file.
public void reset()
throws IOException
reset in class ReaderUnsupportedOperationException - 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.
public long skip(long numberOfChars)
throws IOException
skip in class ReadernumberOfChars - The number of characters to skip.
-1
if the end of file has been reached and
throwEofException is set to false.
EOFException - if the end of file is reached and
throwEofException is set to true.
IOException - if trying to read past the end of file.protected int processChar()
read() method.
This implementation returns zero.
protected void processChars(char[] chars,
int offset,
int length)
read(char[], offset, length)
method.
This implementation leaves the character array unchanged.
chars - The character arrayoffset - The offset to start at.length - The number of characters.
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