ThisTest

// Fig. 8.4: ThisTest.java
// this used implicity and explicitly to refer to members of an object.

public class ThisTest
{
    public static void main( String[] args)
    {
        SimpleTime time = new SimpleTime( 15, 30, 19 );
        System.out.println( time.buildString() );
    } // end main
} // end class ThisTest

// class SimpleTime demonstrates the "this" reference
class SimpleTime
{
    private int hour; // 0-23
    private int minute; // 0-59
    private int second; // 0-59

    // if the constructor uses parameter names identical to
    // instance variable names the "this" refrence is
    // required to distinguish between the names
    public SimpleTime( int hour, int minute, int second )
    {
        this.hour = hour; // set "this" object's hour
        this.minute = minute; // set "this" object's minute
        this.second = second; // set "this" object's second
    } // end SimpleTIme constructor

    // use explicit and implicit "this" to call toUniversalString
    public String buildString()
    {
        return String.format( "%24s: %s\n%24s: %s",
            "this.toUniversalString()", this.toUniversalString(),
            "toUniversalString()", toUniversalString() );
    } // end method buildString

    // convert to String in universal-time format (HH:MM:SS)
    public String toUniversalString()
    {
        //"this is not required here to access instance variables,
        // becaus methos does not have local vairables with same
        // names as instance variables
        return String.format( "%02d:%02d:%02d",
            this.hour, this.minute, this.second );
    } // end method to Universal String
} // end class SimpleTime