.Open CS320/17 Exception and Event Handling and Chapter 14
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.Row Prev 16	Concurrency and Java	Chapter 13  not sect'n 9	lab16 Java102
.Row 17	Exceptions	Chapter 14	lab17 Java103
.Row Next 18	Prolog	Chapter 2  sect'n 13 +  Prolog  Handout	lab18 Prolog101
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. Preparation
              Study chapter 14 and these notes. Focus on C++ and Java 
exceptions.
              Answer review questions at the end of the handout
              Hand in answers to 2 or more review questions.

Key ideas to remember:
.List
        exception
        handling an exception
        exception handler
        raising an exception
        disabling an exception
        built in exception
        event
        event handler
.Close.List
Don't memorize all the exceptions and event types in Java. These details 
are needed to develop code, not on the final. Instead book-mark(put in 
favorites) the online
WWW documentation
.See http://java.sun.com/j2se/1.4.2/docs/api/index.html
that Sun maintains.

The CSci202 book "Scansholm" and Bjarne Stroustroup's LRM make a
useful reference for C++ programmers.  They won't be on the final.

. Exception Handling Principles
Convert_exceptions::=`If you can not handle an exception then convert it to a higher level exception`.
Name_the_problem_not_the_thrower::=`name exceptions to indicate what is wrong not where it came from`.
centralize_error_logging::pattern. Have a single object that is responsible for recording bad things.
standard_error_dialog::pattern. Have a standard user interface for reporting and sorting out errors.

. Notes on Chapter 14
Event handling arrived late in the computer languages but is now a vital 
part of programming(Section 14.6.2...). GUIs (14.6.1) are easier than they
look!

Exceptions are not a late arrival.  
They are natural way to cope with Murphy's Law: If anything can go wrong, 
it will.

Note.  History of C++/Java exceptions.  The `throw` and `catch` terminology
comes form ..... CLOS LISP.

. Exceptions in Java (Missing point in book)
The book does not mention a property of RuntimeException in Java. Normally
the compiler rejects code that fails to catch a thrown Exception and 
doesn't declare that it throws it. This is not true of RuntimeExceptions. A
welcome relief. You should spend some time in next sessions's lab exploring
the Throwable hierarchy
.See http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Throwable.html
in Sun's documentation.

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. Class Work
.See ./17q.html
. Lab Work
.See ./lab/17.html
. Next
.See ./18.html