frog.java

think in java TIJ-3rd-edition-code.zip

//: c07:Frog.java
// Testing finalize with inheritance.
import com.bruceeckel.simpletest.*;

class DoBaseFinalization {
  public static boolean flag = false;
}

class Characteristic {
  String s;
  Characteristic(String c) {
    s = c;
    System.out.println(
      "Creating Characteristic " + s);
  }
  protected void finalize() {
    System.out.println(
      "finalizing Characteristic " + s);
  }
}

class LivingCreature {
  Characteristic p =
    new Characteristic("is alive");
  LivingCreature() {
    System.out.println("LivingCreature()");
  }
  protected void finalize() throws Throwable {
    System.out.println(
      "LivingCreature finalize");
    // Call base-class version LAST!
    if(DoBaseFinalization.flag)
      super.finalize();
  }
}

class Animal extends LivingCreature {
  Characteristic p =
    new Characteristic("has heart");
  Animal() {
    System.out.println("Animal()");
  }
  protected void finalize() throws Throwable {
    System.out.println("Animal finalize");
    if(DoBaseFinalization.flag)
      super.finalize();
  }
}

class Amphibian extends Animal {
  Characteristic p =
    new Characteristic("can live in water");
  Amphibian() {
    System.out.println("Amphibian()");
  }
  protected void finalize() throws Throwable {
    System.out.println("Amphibian finalize");
    if(DoBaseFinalization.flag)
      super.finalize();
  }
}

public class Frog extends Amphibian {
  Frog() {
    System.out.println("Frog()");
  }
  protected void finalize() throws Throwable {
    System.out.println("Frog finalize");
    if(DoBaseFinalization.flag)
      super.finalize();
  }
  public static void main(String[] args) {
    SimpleTest monitor =
      new SimpleTest("Frog");
    if(args.length != 0 &&
       args[0].equals("finalize"))
       DoBaseFinalization.flag = true;
    else
      System.out.println("Not finalizing bases");
    new Frog(); // Instantly becomes garbage
    System.out.println("Bye!");
    // Force finalizers to be called:
    System.gc();
    try {
      Thread.currentThread().sleep(500);
    }
    catch(InterruptedException e) {}
    monitor.expectIgnoreOrder(new String[] {
      "Not finalizing bases",
      "Creating Characteristic is alive",
      "LivingCreature()",
      "Creating Characteristic has heart",
      "Animal()",
      "Creating Characteristic can live in water",
      "Amphibian()",
      "Frog()",
      "Bye!",
      "Frog finalize",
      "finalizing Characteristic is alive",
      "finalizing Characteristic has heart",
      "finalizing Characteristic can live in water"});
  }
} ///:~