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