1.5.1 Defining Classes to Represent Compound Data

In Section 1.2, we introduced a class definition for department directory entries and briefly explained its various parts. We will now review the syntactic structure and semantic behavior of classes in more detail.

Recall that a directory entry is a object with the following fields and methods:

Fields:
    String name;
    String address;
    String phone;
	
Methods:
    String getName();
    String getAddress();
    String getPhone();

In Java, we can express the data definition by the class

class Entry {
  /* fields */
  String name;	
  String address;
  String phone;

  /* accessors */
  String getName() { return this.name; }
  String getAddress() { return this.address; }
  String getPhone() { return this.phone; }
}

But this class definition is not complete because it does not define a suitable constructor for creating and initializing objects of this form.