/*
Author  : Michael Robinson
Program : IteratorsAddNextRemove.java
Purpose : How to create a Java ArrayList using Iterators.
          Shows how to add elements to an ArrayList
          How to use itr.hasNext(), itr.next(), itr.remove() 
          How to get and print data items using for loops.
       
Updated : July 2nd, 2099
*/
    

import java.util.ArrayList;
import java.util.Iterator;


public class IteratorsAddNextRemove
{
    public static String label =
                  "------------------------------------------";
        
    public static void alphaArrayList()
    {

        System.out.println( label );
        System.out.println( " Processing ArrayList of String" +
                            " data type " );
        System.out.println( "           using ITERATORS        " );                  
        System.out.println( label );
        System.out.println( " Creating ArrayList..." );

        //create an ArrayList object
        ArrayList<String> arrayList = new ArrayList<String>();

        
        System.out.println( " Adding data elements to the" +
                            " ArrayList..." );

        //Add and displaying elements to ArrayList using:
        arrayList.add( "a" );
        System.out.println( " arrayList.add( \"a\" )" ); 
        arrayList.add( "b" );
        System.out.println( " arrayList.add( \"b\" )" );         
        arrayList.add( "c" );
        System.out.println( " arrayList.add( \"c\" )" );         
        arrayList.add( "d" );
        System.out.println( " arrayList.add( \"d\" )" );         
        arrayList.add( "e" );
        System.out.println( " arrayList.add( \"e\" )" );         
        arrayList.add( "f" );
        System.out.println( " arrayList.add( \"f\" )" );         
     
        System.out.println( "\n Getting data elements from the" +
                            " ArrayList" );
        System.out.println( " Iterating through ArrayList " +
                            " elements..." );

        //This is a loop type class which allows to loop thru 
        //the ArrayList
        Iterator<String> itr = arrayList.iterator();

        //use hasNext() and next() methods of Iterator to 
        //iterate through the ArrayLis
        while( itr.hasNext() )
        {
           System.out.print( " " + itr.next() );
           
        }//end while( itr.hasNext() )
        
        //now remove elements !!! always remove from the highest 
        //to the lowest location
        System.out.println( "\n\n Removing data elements from " +
                            "the ArrayList on index 3 = "
 +
                            arrayList.get(3) +
              "\n                                          and" +
                            " index 1 = " +
 arrayList.get(1) );
        
        arrayList.remove(3);
        arrayList.remove(1);

        System.out.println();
        System.out.println( " Getting data elements from the " +
                            "  ArrayList after removing" );
        System.out.println( " Iterating through ArrayList " +
                            " elements..." );

        //reset iterator to beginning of ArrayList
  
        itr = arrayList.iterator(); 
        
        //use hasNext() and next() methods of Iterator to iterate 
        //through the ArrayLis
        while( itr.hasNext() )
        {
           System.out.print( " " + itr.next() );
           
        }//end while( itr.hasNext() )

        System.out.println( "\n\n" );
      
    }//end public static void alphaArrayList()

    
    public static void numericArrayList()
    {
        System.out.println( label );
         
        System.out.println( " Processing ArrayList of Integer " +
                            " data type" );
        System.out.println( "           using ITERATORS" );
        System.out.println( label );
        
        
        System.out.println( " Creating ArrayList..." );
        //create an ArrayList object
        ArrayList<Integer> arrayList = new ArrayList<Integer>();
     
        System.out.println( " Adding data elements to the" +
                            " ArrayList..." );        
        //Add elements to Arraylist using
        arrayList.add( 1100 );
        System.out.println( " arrayList.add( \"1100\" )" ); 
        arrayList.add( 2100 );
        System.out.println( " arrayList.add( \"2100\" )" );         
        arrayList.add( 3100 );
        System.out.println( " arrayList.add( \"3100\" )" );         
        arrayList.add( 4100 );
        System.out.println( " arrayList.add( \"4100\" )" );         
        arrayList.add( 5100 );
        System.out.println( " arrayList.add( \"5100\" )" );         
        arrayList.add( 6100 );
        System.out.println( " arrayList.add( \"6100\" )" );         
     
        System.out.println( "\n Getting data elements in the" + 
                            "ArrayList" );
        System.out.println( " Iterating through ArrayList" +
                            " elements..." );

        //This is a loop type class which allows to loop 
        //thru the ArrayList
        Iterator<Integer> itr = arrayList.iterator();

        //use hasNext() and next() methods of Iterator to 
        //iterate through the ArrayLis
        while( itr.hasNext() )
        {
           System.out.print( " " + itr.next());
           
        }//end while( itr.hasNext() )
         
        System.out.println( "\n\n Removing data elements from " +
                            "the ArrayList on index 3 = "
 +
                             arrayList.get(3) + 
"\n" +
                   "                                          " +
                            " and index 1 = " + arrayList.get(1) );

        //now remove some !!! always remove from the height to 
        //the lowest
        arrayList.remove(3);
        arrayList.remove(1);

        System.out.println( "\n Getting data elements from the " +
                            "ArrayList after removing" );
        System.out.println( " Iterating through ArrayList" +
                            " elements..." );

        //reset iterator to beginning of ArrayList
        itr = arrayList.iterator(); 
        
        //use hasNext() and next() methods of Iterator to iterate
        //through the ArrayList
        while( itr.hasNext() )
        {
           System.out.print( " " + itr.next() );
           
        }//end while( itr.hasNext() )
        
        System.out.println();
        
    }//end public static void numericArrayList()
    
    
    public static void addNextRemoveIterator()
    {
        System.out.println( label );
        
        System.out.println( " Processing ArrayList of String data" +
                            " type " );
        System.out.println( "           using ITERATORS" );        
            
        System.out.println( label );
      
        System.out.println( " Creating ArrayList..." );

        //create an ArrayList object
        ArrayList<String> arrayList = new ArrayList<String>();

        System.out.println( " Adding data elements to the" +
                            " ArrayList..." );
        //Add elements to Arraylist using
        arrayList.add( "A" );
        System.out.println( " arrayList.add( \"A\" )" );
      
        arrayList.add( "B" );
        System.out.println( " arrayList.add( \"B\" )" );
        arrayList.add( "C" );
        System.out.println( " arrayList.add( \"C\" )" );
        arrayList.add( "D" );
        System.out.println( " arrayList.add( \"D\" )" );
        arrayList.add( "E" );
        System.out.println( " arrayList.add( \"E\" )" );
        arrayList.add( "F" );
        System.out.println( " arrayList.add( \"F\" )" );
     
        System.out.println( "\n Getting data elements from the" +    
                            "ArrayList" );
        System.out.println( " Iterating through ArrayList " +
                            " elements..." );

        //This is a loop type class which allows to loop thru 
        //the ArrayList
        Iterator<String> itr = arrayList.iterator();

        String temp = "";
        //use hasNext() and next() methods of Iterator to iterate 
        //through the ArrayLis
        while( itr.hasNext() )
        {
            if( itr.hasNext() )
            {
                System.out.println( "\n\n itr.hasNext() = " +
                                    itr.hasNext() );
                temp = itr.next();
                System.out.println( " itr.next() = " + temp );
                System.out.println( " removing =   " + temp );                
                itr.remove();                
            }
            else
            {
                System.out.println( "\n The Arraylist is empty" +  
                                    "itr.hasNext() = [" +
                                     itr.hasNext() + "]" );
            }//end if( itr.hasNext() )

        }//end while( itr.hasNext() )
        
        if( itr.hasNext() )
        {
            System.out.println( "\n itr.hasNext() = " + 
                                 itr.hasNext() );
        }
        else
        {
            System.out.println( "\n itr.hasNext() = [" +
                                 itr.hasNext() + "]" );
            System.out.println( " The Arraylist is empty" +
                                " itr.hasNext() = [" + 
                                  itr.hasNext() + "]" );
        }//end if( itr.hasNext() )

        System.out.println();
        System.out.println( " Getting data elements from the " +   
                            " ArrayList after removing" );
        System.out.println( " Iterating through ArrayList " +
                            " elements" );

        //reset iterator to beginning of ArrayList
        itr = arrayList.iterator(); 
        
        System.out.print( " [" );
        //use hasNext() and next() methods of Iterator to iterate
        //through the ArrayLis

        while( itr.hasNext() )
        {
           System.out.print( " " + itr.next() );
           
        }//end while( itr.hasNext() )

        System.out.print( "]\n\n" );
      
    }//end public static void addNextRemoveIterator()


    public static void main(String[] args) 
    {
        alphaArrayList();
        numericArrayList();
        addNextRemoveIterator();
        
    }//end public static void main(String[] args) 
    
}//end public class IteratorsAddNextRemove