Desktop-as-a-Service Designed for Any Cloud ? Nutanix Frame

Bruce Eckel's Thinking in Java Contents | Prev | Next

  1. Create a new class called Gerbil with an int gerbilNumber that’s initialized in the constructor (similar to the Mouse example in this chapter). Give it a method called hop( ) that prints out which gerbil number this is and that it’s hopping. Create a Vector and add a bunch of Gerbil objects to the Vector. Now use the elementAt( ) method to move through the Vector and call hop( ) for each Gerbil.
  2. Modify Exercise 1 so you use an Enumeration to move through the Vector while calling hop( ).
  3. In AssocArray.java, change the example so it uses a Hashtable instead of an AssocArray.
  4. Take the Gerbil class in Exercise 1 and put it into a Hashtable instead, associating the name of the Gerbil as a String (the key) for each Gerbil (the value) you put in the table. Get an Enumeration for the keys( ) and use it to move through the Hashtable, looking up the Gerbil for each key and printing out the key and telling the gerbil to hop( ).
  5. Change Exercise 1 in Chapter 7 to use a Vector to hold the Rodents and an Enumeration to move through the sequence of Rodents. Remember that a Vector holds only Objects so you must use a cast (i.e.: RTTI) when accessing individual Rodents.
  6. (Intermediate) In Chapter 7, locate the GreenhouseControls.java example, which consists of three files. In Controller.java, the class EventSet is just a collection. Change the code to use a Stack instead of an EventSet. This will require more than just replacing EventSet with Stack; you’ll also need to use an Enumeration to cycle through the set of events. You’ll probably find it easier if at times you treat the collection as a Stack and at other times as a Vector.
  7. (Challenging). Find the source code for Vector in the Java source code library that comes with all Java distributions. Copy this code and make a special version called intVector that holds only ints. Consider what it would take to make a special version of Vector for all the primitive types. Now consider what happens if you want to make a linked list class that works with all the primitive types. If parameterized types are ever implemented in Java, they will provide a way to do this work for you automatically (as well as many other benefits).
  8. e


  • There are no comments yet. Be the first to comment!

  • You must have javascript enabled in order to post comments.

Leave a Comment
  • Your email address will not be published. All fields are required.

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date