ArrayListCollection.java

// Fig. 7.24: ArrayListCollection.java
// Generic ArrayList collection demonstration.
import java.util.ArrayList;

public class ArrayListCollection
{
   public static void main(String[] args)
   {
      // create a new ArrayList of Strings with an initial capacity of 10
      ArrayList<String> items = new ArrayList<String>(); 

      items.add("red"); // append an item to the list          
      items.add(0, "yellow"); // insert "yellow" at index 0

      // header
      System.out.print(
         "Display list contents with counter-controlled loop:"); 

      // display the colors in the list
      for (int i = 0; i < items.size(); i++)
         System.out.printf(" %s", items.get(i));

      // display colors using enhanced for in the display method
      display(items,
         "%nDisplay list contents with enhanced for statement:");

      items.add("green"); // add "green" to the end of the list
      items.add("yellow"); // add "yellow" to the end of the list      
      display(items, "List with two new elements:"); 

      items.remove("yellow"); // remove the first "yellow"
      display(items, "Remove first instance of yellow:"); 

      items.remove(1); // remove item at index 1
      display(items, "Remove second list element (green):"); 

      // check if a value is in the List
      System.out.printf("\"red\" is %sin the list%n",
         items.contains("red") ? "": "not ");

      // display number of elements in the List
      System.out.printf("Size: %s%n", items.size());
   } 

   // display the ArrayList's elements on the console
   public static void display(ArrayList<String> items, String header)
   {
      System.out.print(header); // display header

      // display each element in items
      for (String item : items)
         System.out.printf(" %s", item);

      System.out.println();
   } 
} // end class ArrayListCollection