38 lines
913 B
Java
38 lines
913 B
Java
|
//: housekeeping/TerminationCondition.java
|
|||
|
|
// <20>2015 MindView LLC: see Copyright.txt
|
|||
|
|
// Using finalize() to detect an object that
|
|||
|
|
// hasn't been properly cleaned up.
|
|||
|
|
import com.mindviewinc.util.*;
|
|||
|
|
|
|||
|
|
class Book {
|
|||
|
|
boolean checkedOut = false;
|
|||
|
|
Book(boolean checkOut) {
|
|||
|
|
checkedOut = checkOut;
|
|||
|
|
}
|
|||
|
|
void checkIn() {
|
|||
|
|
checkedOut = false;
|
|||
|
|
}
|
|||
|
|
@Override
|
|||
|
|
protected void finalize() {
|
|||
|
|
if(checkedOut)
|
|||
|
|
System.out.println("Error: checked out");
|
|||
|
|
// Normally, you'll also do this:
|
|||
|
|
// super.finalize(); // Call the base-class version
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public class TerminationCondition {
|
|||
|
|
public static void main(String[] args) {
|
|||
|
|
Book novel = new Book(true);
|
|||
|
|
// Proper cleanup:
|
|||
|
|
novel.checkIn();
|
|||
|
|
// Drop the reference, forget to clean up:
|
|||
|
|
new Book(true);
|
|||
|
|
// Force garbage collection & finalization:
|
|||
|
|
System.gc();
|
|||
|
|
new Sleep(1); // Delay
|
|||
|
|
}
|
|||
|
|
} /* Output:
|
|||
|
|
Error: checked out
|
|||
|
|
*///:~
|