File I/O - Java - page 543

Display 10.6 Methods in the Class Scanner (part 4 of 4)

public boolean hasNextBoolean()

Returns true if the next token is a well-formed string representation of a boolean value; otherwise
returns false .
Throws an IllegalStateException if the Scanner stream is closed.

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 file named sally so that
your program can read input from the text file 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 file?

(continued)