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();
	}
}