对象的插入排序

/*
 * objectSort.java
 * demonstrate sorting objects (use insertion sort)
 */
public class Person {
    private String firstname;
    private String lastname;
    private int age;
    
    // constructor
    public Person(String lastname, String firstname, int age) {
        this.lastname = lastname;
        this.firstname = firstname;
        this.age = age;
    }
    
    // get lastname
    public String getLast() {
        return lastname;
    }
    
    // display
    public void displayPerson() {
        System.out.print(" Lastname:" + lastname);
        System.out.print(" Firstname:" + firstname);
        System.out.print(" Age:" + age);
    }
}
//end class Person
// ---------------------------
public class ArrayInOb {
    private Person[] a;
    private int nElems;
    
    // constructor
    public ArrayInOb(int max) {
        a = new Person[max];
        nElems = 0;
    }
    
    // put element to array
    public void insert(String lastname, String firstname, int age) {
        a[nElems] = new Person(lastname, firstname, age);
        nElems++;
    }
    
    // display
    public void display() {
        for (int j = 0; j < nElems; j++) {
            a[j].displayPerson();
            System.out.println("");
        }
    }
    
    // insert sort
    public void insertSort() {
        int in, out;
        
        for (out = 1; out < nElems; out++) {
            Person temp = a[out];
            in = out;
            
            int compare = a[in-1].getLast().compareTo(temp.getLast());
            while (in > 0 && compare > 0) {
                // shift item to right
                a[in] = a[in-1];
                // go left one position
                --in;           
            }
            // insert marked item
            a[in] = temp;
        }
    }
}
// end class ArrayInOb
// ---------------------------
public class ObjectSortApp {
    
    public static void main(String[] args) {
        int maxSize = 100;
        ArrayInOb arr;
        arr = new ArrayInOb(maxSize);
        
        // put elements into array
        arr.insert("Evans", "Zatty", 24);
        arr.insert("Bvans", "Aatty", 21);
        arr.insert("Avans", "Yatty", 5);
        arr.insert("Tvans", "Xatty", 99);
        
        System.out.println("Before Sorting:");
        arr.display();
        
        System.out.println("After Sorting:");
        arr.insertSort();
        arr.display();
    }
}