Iterator update

Iterator update

Author: nlharri

javacollectionsframeworkexamples/JavaCollectionsFrameworkExamples.java

@@ -3,14 +3,19 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Queue;
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.ListIterator;
+
 
 /**
  *
@@ -25,6 +30,8 @@ public static void main(String[] args) {
         ArrayListVsLinkedList();
         HashMapLinkedHashMapTreeMapTest();
         SetsTest();
+        QueueTest();
+        IteratorTest();
     }
 
     private static final void ArrayListVsLinkedList() {
@@ -183,4 +190,71 @@ private static void SetsTest() {
         System.out.println("-------------------------------------------");
 
     }
+    
+    private static void QueueTest() {
+        Queue<Integer> arrayBlockingQueue = new ArrayBlockingQueue<Integer>(3);
+        try {
+            arrayBlockingQueue.add(10);
+            arrayBlockingQueue.add(20);
+            arrayBlockingQueue.add(30);
+        } catch (IllegalStateException e) {
+            e.printStackTrace();
+        }
+        
+        System.out.println(arrayBlockingQueue);
+        Integer val = arrayBlockingQueue.remove();
+        System.out.println(val);
+        System.out.println(arrayBlockingQueue);
+        val = arrayBlockingQueue.remove();
+        System.out.println(val);
+        System.out.println(arrayBlockingQueue);
+        val = arrayBlockingQueue.remove();
+        System.out.println(val);
+    }
+
+    private static void IteratorTest() {
+        LinkedList<String> animals = new LinkedList<String>();
+        animals.add("fox");
+        animals.add("meerkat");
+        animals.add("guinea pig");
+        animals.add("rabbit");
+        animals.add("turtle");
+        
+        System.out.println("\"Old\", classical way of iteration, removing \"guinea pig\":");
+        System.out.println("-------------------------------------------");
+        Iterator<String> it = animals.iterator();
+        while (it.hasNext()) {
+            String animal = it.next();
+            System.out.println(animal);
+            if (animal.equals("guinea pig")) {
+                it.remove();
+            }
+        }
+        System.out.println("-------------------------------------------");
+        System.out.println("Modern way of iteration (>=Java5) - cannot remove element during iteration:");
+        System.out.println("(animals.remove() would throw an exception)");
+        System.out.println("-------------------------------------------");
+        for (String animal : animals)  {
+            System.out.println(animal);
+        }
+        System.out.println("-------------------------------------------");
+        System.out.println("Adding items to a list during iteration: ListIterator");
+        System.out.println("-------------------------------------------");
+        ListIterator<String> lit = animals.listIterator();
+        while (lit.hasNext()) {
+            String animal = lit.next();
+            System.out.println(animal);
+            if (animal.equals("turtle")) {
+                lit.add("giraffe");
+            }
+        }
+        System.out.println("-------------------------------------------");
+        System.out.println("After adding \"giraffe\"");
+        System.out.println("-------------------------------------------");
+        lit = animals.listIterator();
+        while (lit.hasNext()) {
+            System.out.println(lit.next());
+        }
+        System.out.println("-------------------------------------------");
+    }
 }