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cs2381: Design Recipe

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Design Recipe for a static method #

To design a static method, follow this design recipe:

  • Javadoc
    • Purpose statement
    • @param lines
    • @return line
  • Stub method
    • static, Name, return type, argument names with types
  • Tests
    • Based on the problem statement, write one or more tests
  • Standard pattern
    • Which argument are you primarily operating on?
    • Based on the type of the primary argument to the method, what’s the normal thing you do with one of those?
  • Write the function body
  • More tests

Design Recipe for an instance method #

To design an instance method, follow this design recipe:

  • Javadoc
    • Purpose statement
    • @param lines
    • @return line
  • Stub method
    • not static, Name, return type, argument names with types
  • Tests
    • Based on the problem statement, write one or more tests
  • Standard pattern
    • Rather than find a primary argument, you’ve got to consider the arguments to the method and the fields of the class.
    • Which thing are you operating on, and how do you normally operate on that type of thing?
  • Write the function body
  • More tests

Design Recipe for a Record #

A Record is a composite data type with a selection of fields and maybe some methods.

Follow this design recipe:

  • Stub record
    • Name, field names with type
  • Javadoc
    • Purpose statement for the record.
    • @author line
    • @param lines for each field
  • Methods
    • For each method, follow the design recipe for a method.

Design Recipe for a Class #

  • Class name
  • Javadoc
    • Think: Is this class to organize data or logic?
      • Normally shouldn’t do both.
      • Static methods hint at a logic class.
      • Non-static fields hint at a data class.
      • If data class, should this be a record?
    • Purpose statement for the record.
    • @author line
  • Methods
    • For each method, follow the design recipe for a method.
    • If data class, consider:
      • Constructor(s)
      • Standard methods: equals, hashCode, toString, getters/setters, etc
      • Should this be immutable (all fields final)?

Design Recipe for an Interface #

  • Interface name
  • Javadoc
    • Purpose statement
    • @author
  • Methods
    • Since these are stub methods, they only need:
      • Stub, with no body
      • Javadoc
  • Note: Methods that implement interface methods should say @Override, which means they don’t need their own Javadoc.

Design Recipe for a Program #

A Java program is a collection of Classes, Records, and Interfaces.

If you design all the pieces, you’ve designed the program.

If you don’t know where to start, you know you need a main class (with a static main method), so start there. As you discover more pieces you need, design those too. Repeat until done.