1	// Example 4.3 ArrayListDemo.java
     2	//
     3	//
     4	// Copyright 2003 Bill Campbell and Ethan Bolker
     5	
     6	// Tell the java compiler that the ArrayList class is in
     7	// the java.util part of the library.
     8	
     9	import java.util.ArrayList; 
    10	
    11	//  Exercise the most important parts of the ArrayList API.
    12	//
    13	// %> java ArrayListDemo
    14	// Create a list containing three SimpleObjects.
    15	// 0    zero
    16	// 1    one
    17	// 2    two
    18	// Replace the object at position 0.
    19	// Put a new object at 2 and push the rest along.
    20	// Print out the list again.
    21	// 0    new zero
    22	// 1    one
    23	// 2    one point five
    24	// 3    two
    25	
    26	public class ArrayListDemo 
    27	{
    28	    public static void main( String[] args ) 
    29	    {
    30	        System.out.println("Create a list containing three SimpleObjects.");
    31	
    32	        // Create a new, empty ArrayList 
    33	        // with the ArrayList constructor.
    34	        ArrayList myList = new ArrayList();
    35	
    36	        // Put three things on it with the add()
    37	        // method - each add appends to the list.
    38	        myList.add(new SimpleObject("zero"));
    39	        myList.add(new SimpleObject("one"));
    40	        myList.add(new SimpleObject("two"));
    41	
    42	        // Print the list with a for loop.
    43	        // size() method tells how long the list is.
    44	        // get(int index) method retrieves value stored at position index
    45	        // The (SimpleObject) cast tells Java what type of thing you got
    46	        for (int i = 0; i < myList.size() ; i++ ) {
    47	            SimpleObject foo = (SimpleObject)myList.get(i); 
    48	            System.out.println(i + "\t" + foo.name);
    49	        }
    50	
    51	        // set(int index) method changes value stored at position index
    52	        System.out.println("Replace the object at position 0.");
    53	        myList.set(0, new SimpleObject("new zero"));
    54	
    55	        System.out.println("Put a new object at 2 and push the rest along.");
    56	        myList.add(2, new SimpleObject("one point five"));
    57	
    58	        System.out.println("Print out the list again.");
    59	        for (int i = 0; i < myList.size() ; i++ ) {
    60	            SimpleObject foo = (SimpleObject)myList.get(i); // note cast!
    61	            System.out.println(i + "\t" + foo.name);
    62	        }
    63	    }
    64	
    65	    // This really simple class exists only to provide 
    66	    // things to put in the ArrayList.
    67	    //
    68	    // It's an inner class, declared inside the ArrayListDemo 
    69	    // class, which is its scope.
    70	    //
    71	    // Since it's visible only here, we are using a public
    72	    // name field rather than a private field and a public
    73	    // getName() 
    74	
    75	    private static class SimpleObject {
    76	    
    77	        public String name;
    78	        
    79	        public SimpleObject( String name ) {
    80	            this.name = name;
    81	        }
    82	    } // end of body of inner class SimpleObject
    83	
    84	} // end of body of ArrayList Demo