Java Reference
In-Depth Information
Display 10.6
Methods in the Class
Scanner
(part 4 of 4)
public
String nextLine()
Returns the rest of the current input line. Note that the line terminator
'\n'
is read and discarded;
it is not included in the string returned.
Throws a
NoSuchElementException
if there are no more lines.
Throws an
IllegalStateException
if the Scanner stream is closed.
public boolean
hasNextLine()
Returns
true
if there is a next line. May wait for a next line to enter the stream.
Throws an
IllegalStateException
if the
Scanner
stream is closed.
public
Scanner useDelimiter(String newDelimiter);
Changes the delimiter for input so that
newDelimiter
will be the only delimiter that separates
words or numbers. See the subsection “Other Input Delimiters” in Chapter 2 for the details. (You
can use this method to set the delimiters to a more complex pattern than just a single string, but we
are not covering that.)
Returns the calling object, but we have always used it as a
void
method.
Unchecked Exceptions
The exception classes
NoSuchElementException
,
InputMismatchException
, and
IllegalStateException
are all unchecked exceptions, which means that an exception
of any of these classes is not required to be caught or declared in a
throws
clause.
Self-Test Exercises
8. Write some code that will create a stream named
fileIn
that is a member of
the class
Scanner
. It should connect the stream to a text fi le named
sally
so
that your program can read input from the text fi le
sally
.
9. Might the method
nextInt
in the class
Scanner
throw an exception? If so,
what type of exception?
10. If the method
hasNextInt
returns
false
, does that mean that reading has
reached the end of the fi le?
