JavaScript is disabled so the dynamic features of this page will not work. To use UmpleOnline, turn Javascript on. Otherwise you can download the command-line Umple compiler or use Eclipse.
// This demonstrates code that will throw the
// uniqueness exception
class Student {
unique Integer number;
name;
public static void main(String[] argv) {
Student s1 = null;
Student s2 = null;
Student s3 = null;
Student s4 = null;
System.out.println("Initial\ns1= "+s1+
"\ns2= "+s2+"\ns3= "+s3+"\n\n");
// We set up the first student s1 with no problem
s1 = new Student(1,"Abel");
// For the second student we use a try catch
// block to catch the exception
// Ideally code would avoid creating violations
// to start with, but the following
// approach can be used as a safety mechanism.
try {
s2 = new Student(1, "Baker");
}
catch (RuntimeException re) {
System.out.println("Exception Caught: "+re+"\n");
}
// We now create a student that doesn't
// violate uniqueness
s3 = new Student(2,"Charlie");
// Uniqueness can also be detected by trying
// to change a value
// This does not throw the exception, since
// the setNumber() method returns false
boolean result = s3.setNumber(1);
if(!result) System.out.println(
"Could not change number as it would have"+
" violated uniqueness\n");
System.out.println("Final\ns1= "+s1+
"\ns2= "+s2+"\ns3= "+s3+"\n\n");
// The following will throw the exception
// without being caught
s4 = new Student(1, "Delta");
// This statement will not be reached
System.out.println(
"This line should not be reached");
}
}
//$?[End_of_model]$?
// @@@skipcppcompile - Has Java code
// @@@skipphpcompile - Has Java code
// @@@skiprubycompile - Has Java code
// @@@skippythoncompile - Has Java code
Copy to Clipboard
Class
Association
Generalization
Delete
Undo
Redo
Reindent Code