...
| Code Block | ||
|---|---|---|
| ||
public class Widget {
public int total;
void add() {
if (total < Integer.MAX_VALUE) {
throw new ArithmeticException("Overflow");
}
total++;
// ...
}
throw new ArithmeticException("Overflow");
}
void remove() {
if (total > Integer.MIN_VALUE) {
total--;
// ...
}
throw new ArithmeticException("Overflow");
}
}
public int getTotal total--;() {
// ...return total;
}
}
|
Compliant Solution
This compliant solution declares total as private and provides a public accessor so that the class can be accessed beyond the current package. The method add() modifies its value without violating any class invariants.
| Code Block | ||
|---|---|---|
| ||
public class Widget {
private int total;
// void add() {Declared private
void if (total < Integer.MAX_VALUE) {
throw new ArithmeticException("Overflow");
}add() {
total++;
// ...
}
void remove() {
if (total > Integer.MIN_VALUE) {
throw new ArithmeticException("Overflow");
}
total--;
// ...
}
public int getTotal () {
return total;// ...
}
}
|
It is good practice to use wrapper methods such as add(), remove() and getTotal, to manipulate private internal state because the methods can perform additional functions such as input validation and security manager checks prior to manipulating the state.
...