/**
 * Zoo.java
 *
 * A short java example, showing :
 *    - objects, their fields (i.e. data), constructors, and methods
 *    - object inheritence ("extends" in java)
 *    - "generics" notation (i.e. Vector<Animal>)
 *    - "static" method (i.e. Zoo.main() class); *not* invoked on instance
 *    - main() is required entry for application executable class
 *    - import of a java language library
 *    - iterator looping syntax, i.e. "for (Vector i: myVector){ foo(i) }"
 *
 * Some awkward bits :
 *    - can't use standard container (Vector) without import
 *    - not easy to make "woof woof woof"
 *    - not easy to instantiate objects dynamically (i.e. from list)
 *    - can't use [0] subscripts on Vector 
 *    - ... but built-in arrays with have fixed lengths.
 *
 * Using it :
 *    $ javac Zoo.java
 *    $ java Zoo
 *    The animals in the zoo say
 *    meow
 *    meow
 *    woof
 *    woof woof woof 
 * 
 * Generating docs:
 *    $ mkdir docs
 *    $ javadoc *.java -d docs
 *    ... but this is only works if classes area declared public
 *    ... and that requires each class be in its own file ClassName.java
 *    ... (Oh Java.)
 *
 * Packaging the .class files (or .class and .java) files :
 *    $ jar cfe zoo.jar Zoo *.class (or *)
 *
 * @see http://cs.marlboro.edu/courses/spring2012/programming/code/java/jims_java_demo/README.txt
 * @author Jim Mahoney
 * @since 2012-04-06
 */

import java.util.Vector;

/**
 * an animal and its characteristic noise
 */
class Animal {

    String noise;             // instance data 

    Animal(){                 // instance constructor, sets data
        noise = "";
    }

    /**
     * @return what the animal says
     */
    public String says(){     // instance method, uses data
        return noise;
    }
}

class Cat extends Animal {    // class inheritence

    Cat(){
        noise = "meow";
    }
}

class Dog extends Animal {

    Dog(){
        noise = "woof";
    }

    Dog(int nWoofs){          // another constructor (different args)
        noise = "";
        for (int i = 0; i < nWoofs; i++){
            noise = noise + "woof ";
        }
    }
}

/**
 * a collection of animals with barnyard noise printing
 */
class Zoo {

    Vector<Animal> animals = new Vector<Animal>();  // java "generics" 

    void add(Animal who) {
            animals.add(who);
    }

    static void println(String message){
        System.out.println(message);
    }

    void printNoises(){
        println("The animals in the zoo say");
        for (Animal who : animals){
            println(who.says());
        }
    }

    public static void main(String[] args) {
        Zoo z = new Zoo();
        for (int i = 0; i < 2 ; i++){
            z.add(new Cat());
        }
        z.add(new Dog());
        z.add(new Dog(3));
        z.printNoises();
        println("");
        println("The first animal says '" + z.animals.get(0).says() + "'");
        println("The last says '" + z.animals.lastElement().says() + "'");
    }
}