WrClasses-WE3-P1

Section 9.7 WrClasses-WE3-P1

Subgoals for Writing a Class.

Pick a name for the class, is usually a noun
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Differentiate class-level static vs. instance/object-level variables
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Differentiate class-level static vs. instance/object behaviors/methods
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Define instance variables (that you want to be interrelated)
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1. Name
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2. Data Type
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3. private
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Define class variables static as needed
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1. Name
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2. Data Type
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3. public / private / final
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Create constructor (behavior) that creates initial state of object
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1. Overloaded constructor (with as many parameters)
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2. public
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3. Same name as class
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4. No return type
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5. Default - no parameters
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6. Logic - initialize all variables
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7. Repeat as needed, adding parameters
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Create 1 accessor and 1 mutator behaviors per attribute
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1. Accessors
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  1. Name is get_<attr_name>
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  2. Public
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  3. Return type same data type as attribute
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  4. No parameters
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  5. Logic - return value
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2. Mutators
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  1. Name is set_<attr_name>
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  2. Public
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  3. Return type is void
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  4. Parameter is same data type as attribute
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  5. Logic validates input parameter and sets attribute value
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Write toString method
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1. public
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2. Returns String
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3. No parameters
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4. Logic - convert needed attributes to a format that can be printed
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Write equals method
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1. public
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2. Returns boolean
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3. Parameter - instance of the class
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4. Logic - compare attributes for equity
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Create additional methods as needed
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Subsection 9.7.1 Classes-WE3-P1

Consider the SongType class you began in an earlier exercise, as illustrated in the following UML diagram.

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Fill in the blanks for the following code:

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public class SongType {
   //attributes declared here
   //...

   //getters/accessors
   public ___A___ getTitle () {
      ___B___ ___C___;
   }
   ___D___ String ___E___ () {
      ___F___ artist;
   }
   public ___G___ getLength () {
      ___H___ ___I___;
   }

   //setters/mutators
   public ___J___ setTitle (String n) {
      title = ___K___;
   }
   ___L___ void setArtist (___M___ n) {
      artist = ___N___;
   }
   public ___O___ setLength (___P___ n) {
      if (n > 0)
         ___Q___ = n;
   }
}