/*
    *  Licensed to the Apache Software Foundation (ASF) under one
    *  or more contributor license agreements.  See the NOTICE file
    *  distributed with this work for additional information
    *  regarding copyright ownership.  The ASF licenses this file
    *  to you under the Apache License, Version 2.0 (the
    *  "License"); you may not use this file except in compliance
    *  with the License.  You may obtain a copy of the License at
    *  
   *    http://www.apache.org/licenses/LICENSE-2.0
   *  
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License. 
   *  
   */
  package org.apache.mina.util;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import java.util.Iterator;
  
  import org.junit.Before;
  import org.junit.Test;
  
  /**
   * Tests {@link org.apache.mina.util.CircularQueue}
   * 
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public class CircularQueueTest {
      private volatile int pushCount;
      private volatile int popCount;
  
      @Before
      public void setUp() {
          pushCount = 0;
          popCount = 0;
      }
  
      @Test
      public void testRotation() {
          CircularQueue<Integer> q = new CircularQueue<Integer>(); // DEFAULT_CAPACITY = 4
          testRotation0(q);
      }
  
      @Test
      public void testExpandingRotation() {
          CircularQueue<Integer> q = new CircularQueue<Integer>(); // DEFAULT_CAPACITY = 4
          for (int i = 0; i < 10; i++) {
              testRotation0(q);
  
              // make expansion happen
              int oldCapacity = q.capacity();
              for (int j = q.capacity(); j >= 0; j--) {
                  q.offer(new Integer(++pushCount));
              }
  
              assertTrue(q.capacity() > oldCapacity);
              testRotation0(q);
          }
      }
  
      private void testRotation0(CircularQueue<Integer> q) {
          for (int i = 0; i < q.capacity() * 7 / 4; i++) {
              q.offer(new Integer(++pushCount));
              assertEquals(++popCount, q.poll().intValue());
          }
      }
  
      @Test
      public void testRandomAddOnQueue() {
          CircularQueue<Integer> q = new CircularQueue<Integer>();
          // Create a queue with 5 elements and capacity 8;
          for (int i = 0; i < 5; i++) {
              q.offer(new Integer(i));
          }
  
          q.add(0, new Integer(100));
          q.add(3, new Integer(200));
          q.add(7, new Integer(300));
  
          Iterator<Integer> i = q.iterator();
          assertEquals(8, q.size());
          assertEquals(new Integer(100), i.next());
          assertEquals(new Integer(0), i.next());
          assertEquals(new Integer(1), i.next());
          assertEquals(new Integer(200), i.next());
          assertEquals(new Integer(2), i.next());
          assertEquals(new Integer(3), i.next());
          assertEquals(new Integer(4), i.next());
          assertEquals(new Integer(300), i.next());
  
          try {
             i.next();
             fail();
         } catch (Exception e) {
             // an exception signifies a successfull test case
             assertTrue(true);            
         }
     }
 
     @Test
     public void testRandomAddOnRotatedQueue() {
         CircularQueue<Integer> q = getRotatedQueue();
 
         q.add(0, new Integer(100)); // addFirst
         q.add(2, new Integer(200));
         q.add(4, new Integer(300));
         q.add(10, new Integer(400));
         q.add(12, new Integer(500)); // addLast
 
         Iterator<Integer> i = q.iterator();
         assertEquals(13, q.size());
         assertEquals(new Integer(100), i.next());
         assertEquals(new Integer(0), i.next());
         assertEquals(new Integer(200), i.next());
         assertEquals(new Integer(1), i.next());
         assertEquals(new Integer(300), i.next());
         assertEquals(new Integer(2), i.next());
         assertEquals(new Integer(3), i.next());
         assertEquals(new Integer(4), i.next());
         assertEquals(new Integer(5), i.next());
         assertEquals(new Integer(6), i.next());
         assertEquals(new Integer(400), i.next());
         assertEquals(new Integer(7), i.next());
         assertEquals(new Integer(500), i.next());
 
         try {
             i.next();
             fail();
         } catch (Exception e) {
             // an exception signifies a successfull test case
             assertTrue(true);
         }
     }
 
     @Test
     public void testRandomRemoveOnQueue() {
         CircularQueue<Integer> q = new CircularQueue<Integer>();
 
         // Create a queue with 5 elements and capacity 8;
         for (int i = 0; i < 5; i++) {
             q.offer(new Integer(i));
         }
 
         q.remove(0);
         q.remove(2);
         q.remove(2);
 
         Iterator<Integer> i = q.iterator();
         assertEquals(2, q.size());
         assertEquals(new Integer(1), i.next());
         assertEquals(new Integer(2), i.next());
 
         try {
             i.next();
             fail();
         } catch (Exception e) {
             // an exception signifies a successfull test case
             assertTrue(true);
         }
     }
 
     @Test
     public void testRandomRemoveOnRotatedQueue() {
         CircularQueue<Integer> q = getRotatedQueue();
 
         q.remove(0); // removeFirst
         q.remove(2); // removeLast in the first half
         q.remove(2); // removeFirst in the first half
         q.remove(4); // removeLast
 
         Iterator<Integer> i = q.iterator();
         assertEquals(4, q.size());
         assertEquals(new Integer(1), i.next());
         assertEquals(new Integer(2), i.next());
         assertEquals(new Integer(5), i.next());
         assertEquals(new Integer(6), i.next());
 
         try {
             i.next();
             fail();
         } catch (Exception e) {
             // an exception signifies a successfull test case
             assertTrue(true);            
         }
     }
     
     @Test
     public void testExpandAndShrink() throws Exception {
         CircularQueue<Integer> q = new CircularQueue<Integer>();
         for (int i = 0; i < 1024; i ++) {
             q.offer(i);
         }
         
         assertEquals(1024, q.capacity());
         
         for (int i = 0; i < 512; i ++) {
             q.offer(i);
             q.poll();
         }
         
         assertEquals(2048, q.capacity());
         
         for (int i = 0; i < 1024; i ++) { 
             q.poll();
         }
         
         assertEquals(4, q.capacity());
     }
 
     private CircularQueue<Integer> getRotatedQueue() {
         CircularQueue<Integer> q = new CircularQueue<Integer>();
 
         // Ensure capacity: 16
         for (int i = 0; i < 16; i++) {
             q.offer(new Integer(-1));
         }
         q.clear();
 
         // Rotate it
         for (int i = 0; i < 12; i++) {
             q.offer(new Integer(-1));
             q.poll();
         }
 
         // Now push items
         for (int i = 0; i < 8; i++) {
             q.offer(new Integer(i));
         }
 
         return q;
     }
 }