Java enum: Creating an Enum
/*
License for Java 1.5 'Tiger': A Developer's Notebook
(O'Reilly) example package
Java 1.5 'Tiger': A Developer's Notebook (O'Reilly)
by Brett McLaughlin and David Flanagan.
ISBN: 0-596-00738-8
You can use the examples and the source code any way you want, but
please include a reference to where it comes from if you use it in
your own products or services. Also note that this software is
provided by the author "as is", with no expressed or implied warranties.
In no event shall the author be liable for any direct or indirect
damages arising in any way out of the use of this software.
*/
import java.io.IOException;
import java.io.PrintStream;
enum Grade { A, B, C, D, F, INCOMPLETE };
class Student {
private String firstName;
private String lastName;
private Grade grade;
public Student(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName() {
return firstName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName() {
return lastName;
}
public String getFullName() {
return new StringBuffer(firstName)
.append(" ")
.append(lastName)
.toString();
}
public void assignGrade(Grade grade) {
this.grade = grade;
}
public Grade getGrade() {
return grade;
}
}
public class GradeTester {
private Student student1, student2, student3;
public GradeTester() {
student1 = new Student("Brett", "McLaughlin");
student2 = new Student("Ben", "Rochester");
student3 = new Student("Dennis", "Erwin");
}
public void testGradeAssignment(PrintStream out) throws IOException {
student1.assignGrade(Grade.B);
student2.assignGrade(Grade.INCOMPLETE);
student3.assignGrade(Grade.A);
}
public void listGradeValues(PrintStream out) throws IOException {
Grade[] gradeValues = Grade.values();
// for loop
for (int i=0; i<gradeValues.length; i++) {
out.println("Allowed value: '" + gradeValues[i] + "'");
}
// for/in loop
for (Grade g : gradeValues ) {
out.println("Allowed value: '" + g + "'");
}
}
public void testSwitchStatement(PrintStream out) throws IOException {
StringBuffer outputText = new StringBuffer(student1.getFullName());
switch (student1.getGrade()) {
case A:
outputText.append(" excelled with a grade of A");
break;
case B: // fall through to C
case C:
outputText.append(" passed with a grade of ")
.append(student1.getGrade().toString());
break;
case D: // fall through to F
case F:
outputText.append(" failed with a grade of ")
.append(student1.getGrade().toString());
break;
case INCOMPLETE:
outputText.append(" did not complete the class.");
break;
default:
outputText.append(" has a grade of ")
.append(student1.getGrade().toString());
break;
}
out.println(outputText.toString());
}
public static void main(String[] args) {
try {
GradeTester tester = new GradeTester();
tester.testGradeAssignment(System.out);
tester.listGradeValues(System.out);
tester.testSwitchStatement(System.out);
} catch (Exception e) {
e.printStackTrace();
}
}
}
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