Motivation
JavaPatterns is the project in which I practice, and demonstrate, software design patterns, as implemented in Java.
It presently contains implementations of the following patterns:
Behavioral
Strategy
The interface Algorithm with the execute() method is concretely implemented by the SearchAlgorithm and
TranslationAlgorithm classes. The Developer object takes an Algorithm in its constructor, on which it then
invokes the execute() method without needing to know the type of algorithm it is executing.
The DeveloperTest class ensures the instantiation and types occur as expected.
Creational
Abstract Factory
The interface Developer defines a generic type of developer object, which is then implemented by the concrete
CSharpDeveloper and JavaDeveloper classes.
The interface DeveloperFactory defines a factory object returning a Developer. It is implemented concretely
by the CSharpDeveloperFactory and JavaDeveloperFactory classes, which return the concrete CSharpDeveloper
and JavaDeveloper objects, respectively, as Developers.
The DeveloperFactoryTest class tests that both JavaDeveloperFactory and CSharpDeveloperFactory return valid
DeveloperFactory objects, and that the newDeveloper() method, declared in the DeveloperFactory interface,
returns valid Developers.
Factory Method
The interface Developer defines a generic type of developer object, which is then implemented by the concrete
ConcreteDeveloper class.
The JavaDeveloper and SQLDeveloper classes both extend ConcreteDeveloper and are the specific types internally
used by the factory.
The DeveloperFactory, with a private constructor to prevent instantiation, contains two methods to return instances
of Developers, newJavaDeveloper() and newSQLDeveloper(). These methods return instances of the above two internal
classes, respectively, but do so as ConcreteDevelopers to hide implementation details from consumers of the factory.
The DeveloperFactoryTest class tests the two factory methods by consuming the API through the Developer interface
and ensuring that the resulting object is not null.
Structural
Adapter
The CoffeeCup object contains a drink() method which returns a Coffee object.
The Freezer method expects a CoffeeCup object for its freeze() method, which returns a boolean (true).
The CoffeeCupAdapterImpl class implements the CoffeeCupAdapter interface, which declares a freezeCup() method.
This method takes a CoffeeCup object, on which it calls drink() to obtain a Coffee object. It passes the
Coffee object into a new Freezer that it instantiates. Finally, it returns the value of calling the Freezer's
freeze() method on the Coffee object it obtained.
The CoffeeCupAdapterImplTest class tests that these classes return valid values, and that the adapter's boolean
return value matches the value obtained by performing the adapter pattern manually (i.e., calling drink() and
instantiating and using an outside Freezer).