examples
The following directories contain programs written in the JOOS language. In
each directory you will find a Makefile which shows how to build the
programs in the directory, i.e. which .java files go together to form
an application.
The following directories contain Java applications (not applets).
AwtDemos :
examples of using the Abstract Windows Toolkit.
Network :
simple examples of interacting over the network.
Simple :
a relatively large collection of simple Java programs.
Threads :
simple multithreaded programs.
The following directories contain Java applets. Once compiled, you
should be able to run any of the .html files in the first two
directories via the JDK appletviewer , or via a browser that
supports Java.
Most examples have been taken from textbooks and modified so that they are
written in JOOS. The changes made to make them into JOOS programs include:
- Making the constructors explicit, and making them conform to JOOS specifications
with an explicit call to the
super constructor.
- Since JOOS does not support constants, all constants (particularly
those from the Java
awt libraries)
must be accessed via nullary functions
found in the JOOS libarary class called JoosConstants . You may refer
to the file
joos/lib/JoosConstants.java to see all of the
constants supported in this manner.
- Since JOOS does not support overloading, the
JOOS external declarations
only support one alternative for each method in Java libraries, usually the most general one.
In some cases, for example the
add()
method in the Container class,
both alternatives are really needed. In this case there is a JOOS
wrapper class called JoosContainer
that provided a new name for
each kind of add() : addString() and addPosition() .
- Some Java libarary classes have static members and/or classes. In
order to get this functionality, one needs to use the appropriate wrapper
JOOS class.
A good example of this is the
JoosDimension class that
provides a wrapper to the Java Dimension class.
- Java has quite a rich class structure to support various kinds of I/O.
All JOOS I/O is simple, and is done using the functions found in the
JoosIO class.
- JOOS does not support exceptions, and so it is not possible to
directly call Java library methods that raise exceptions that must
be caught, i.e. exceptions that are not
RuntimeException s. Thus, some
JOOS libarary classes are provided that wrap the exception raising
methods inside a method that catches the exception and returns true if
an exception was caught, e.g. sleep() in
JoosThread .
- Since JOOS does not support real numbers, and some
awt functions
require real numbers as input (GridBagConstraints ),
there is a JOOS version
(JoosGridBagConstraints ), that uses JoosFractions
to represent non-integers.
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