"Advanced" Java Practice

Java has many advanced features that may take some effort to understand how to use properly (or even well :) but that require very little syntax. In most cases, they may not impact your design dramatically, but they can make your code much cleaner and understanding them well can help you think about design more deeply.

Here are ones we have discussed in class

• Reflection
• Lambdas

To work on this exercise, fork the original project lab_advanced into your own repository so you can edit, commit, and push your group's own changes.

Work in pairs to implement the changes described below to example code we have discussed this semester. Create a commit for each step below as your programming pair completes it.

Bins

• Change the fitDisksAndPrint() method so that it takes an third parameter of type Consumer<List<Integer>> whose instances transform a list in some way (e.g., sort, shuffle, or reverse). Within the fitDisksAndPrint() method, you should simply call the parameter's accept() method with the correct value. Within the main() method, change the calls to the fitDisksAndPrint() method to provide this third parameter using Lambdas rather than writing out the complete code to declare and instantiate class instances that implement Consumer<List<Integer>>.
  

Roulette

• Create a Factory class that manages returning Bet subclasses. Initially, use an array (or perhaps List<Bet>) of hard coded subclasses. The Factory should also handle printing out the menu of choices rather than the Game class doing that.
  
• Change the Factory class to use reflection instead of hardcoding the creation of the Bet subclasses. Initially, hardcode the strings in your collection instead of Bet subclass instances. Note, you will either need to add a default constructor to each Bet subclass or create some logic to provide the description and odds for each subclass. Your implementation does not really matter for this step because the focus here is on understanding reflection, the next step will provide a more general solution.
  
• Create a properties file that maps the complete Bet subclass name to its odds and description (on one line separated by a comma for easy parsing). Read this property file to determine which subclasses your factory should create so that nothing is hardcoded in your Factory class.

Browser

• Change the makeButton() method so that it that takes a String parameter instead of a Lambda and uses reflection to convert that to a method. Change the call to setOnAction() to call invoke() on the Method object created using the given string.
• Change the makeButton() method so that it that only takes one String parameter (i.e., no extra parameter telling it what action to perform). Instead create another properties file that maps the button's key name (the same one used in the original properties file) to the name of the method to invoke when it is pressed. After loading the both properties files, you should be able to use the one given string to look up both the text for the button to display (in the original resource file) and the action for the button to perform (in the new resource file). Again, this reduces the assumptions and what is hardcoded in your program.

Your Projects

If you have completed all of the practice steps, try updating some of your own code with some of these features (such as, enumerated types in Game or Cell Society, lambdas in Cell Society or SLogo, reflection in any program).

Submission

At the end of class, use Gitlab's Merge Request to submit your pair's refactored code to the lab's organization repository. Make sure the NetIDs of everyone in the group are in the title of your Merge Request.