完成LRU算法及修改arrayList小bug

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/ArrayList.java

@@ -4,6 +4,7 @@
 
 /**
  * Created by john on 2017/3/8.
+ *
  * @// TODO: 2017/4/1  实现Iterator 接口
  */
 
@@ -23,7 +24,7 @@ public ArrayList() {
     /**
      * Constructs an list with the specified initial capacity.
      *
-     * @param initialCapacity
+     * @param initialCapacity capacity of arrayList.
      * @throws IllegalArgumentException if the specified initial capacity
      *                                  is negative or zero
      */
@@ -70,7 +71,7 @@ public void add(E element) {
      * @throws IndexOutOfBoundsException {@inheritDoc}
      */
     public void add(int index, E element) {
-        rangeCheckForAdd(index);
+        rangeCheck(index);
         ensureCapacityInternal(size + 1);
         System.arraycopy(elementData, index, elementData, index + 1,
                 size - index);
@@ -85,10 +86,10 @@ public void add(int index, E element) {
      *
      * @param index the index of the element to be removed
      * @return the element that was removed from the list
-     * @throws IndexOutOfBoundsException {@inheritDoc}
+     * @throws IndexOutOfBoundsException {@inheritDoc} index out of B
      */
     public E remove(int index) {
-        rangeCheckForAdd(index);
+        rangeCheck(index);
         Object oldValue = elementData[index];
         int numMoved = size() - index - 1;
         if (numMoved > 0) {
@@ -167,14 +168,6 @@ public Object[] toArray() {
         return Arrays.copyOf(elementData, size());
     }
 
-    /**
-     * A version of rangeCheck used by add and addAll.
-     */
-    private void rangeCheckForAdd(int index) {
-        if (index > size() - 1 || index < 0) {
-            throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
-        }
-    }
 
     /**
      * Constructs an IndexOutOfBoundsException detail message.
@@ -192,7 +185,7 @@ private String outOfBoundsMsg(int index) {
      * which throws an ArrayIndexOutOfBoundsException if index is negative.
      */
     private void rangeCheck(int index) {
-        if (index >= size()) {
+        if (index < 0 || index >= size()) {
             throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
         }
     }

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/Stack.java

@@ -1,5 +1,7 @@
 package com.johnChnia.coding2017.basic;
 
+import com.johnChnia.coding2017.basic.linklist.LinkedList;
+
 import java.util.EmptyStackException;
 
 /**

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/linklist/LRUPageFrame.java

@@ -0,0 +1,128 @@
+package com.johnChnia.coding2017.basic.linklist;
+
+/**
+ * Created by john on 2017/4/6.
+ */
+public class LRUPageFrame {
+
+    private static class Node {
+
+        Node prev;
+        Node next;
+        int pageNum;
+
+        Node() {
+        }
+    }
+
+    private int capacity;
+
+
+    private Node first;// 链表头
+    private Node last;// 链表尾
+
+
+    public LRUPageFrame(int capacity) {
+
+        this.capacity = capacity;
+
+    }
+
+    /**
+     * 获取缓存中的对象
+     *
+     * @param pageNum 对象值
+     */
+    public void access(int pageNum) {
+        if (first == null) {
+            Node node = createNode(pageNum);
+            first = last = node;
+            capacity--;
+        } else if (getNode(pageNum) == null) {
+            if (capacity == 0) {
+                Node lastNode = first;
+                while (lastNode.next != null) {
+                    lastNode = lastNode.next;
+                }
+                lastNode.prev.next = null;
+                last = lastNode.prev;
+                delete(lastNode);
+                capacity++;
+            }
+            Node node = createNode(pageNum);
+            node.next = first;
+            node.prev = null;
+            first.prev = node;
+            first = node;
+            capacity--;
+
+        } else {
+            if (first.pageNum != pageNum) {
+                Node node = getNode(pageNum);
+                if (node.next != null) {
+                    node.prev.next = node.next;
+                    node.next.prev = node.prev;
+                } else {
+                    node.prev.next = null;
+                    last = node.prev;
+                }
+                node.next = first;
+                node.prev = null;
+                first.prev = node;
+                first = node;
+            }
+        }
+
+    }
+
+    /**
+     * 删除节点
+     */
+    private void delete(Node node) {
+        node.pageNum = 0;
+        node.next = null;
+        node.prev = null;
+    }
+
+    /**
+     * @param pageNum 页号
+     * @return 节点
+     */
+    private Node createNode(int pageNum) {
+        Node node = new Node();
+        node.pageNum = pageNum;
+        node.next = null;
+        node.prev = null;
+        return node;
+    }
+
+
+    /**
+     * @param pageNum 页号
+     * @return 如果LRUPageFrame包含该pageNum就返回该节点，否则返回null
+     */
+    private Node getNode(int pageNum) {
+        for (Node node = first; node != null; node = node.next) {
+            if (node.pageNum == pageNum) {
+                return node;
+            }
+        }
+        return null;
+    }
+
+
+    public String toString() {
+        StringBuilder buffer = new StringBuilder();
+        Node node = first;
+        while (node != null) {
+            buffer.append(node.pageNum);
+
+            node = node.next;
+            if (node != null) {
+                buffer.append(",");
+            }
+        }
+        return buffer.toString();
+    }
+
+}

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/linklist/LRUPageFrameTest.java

@@ -0,0 +1,30 @@
+package com.johnChnia.coding2017.basic.linklist;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+
+public class LRUPageFrameTest {
+
+    @Test
+    public void testAccess() {
+        LRUPageFrame frame = new LRUPageFrame(3);
+        frame.access(7);
+        frame.access(0);
+        frame.access(1);
+        Assert.assertEquals("1,0,7", frame.toString());
+        frame.access(2);
+        Assert.assertEquals("2,1,0", frame.toString());
+        frame.access(0);
+        Assert.assertEquals("0,2,1", frame.toString());
+        frame.access(0);
+        Assert.assertEquals("0,2,1", frame.toString());
+        frame.access(3);
+        Assert.assertEquals("3,0,2", frame.toString());
+        frame.access(0);
+        Assert.assertEquals("0,3,2", frame.toString());
+        frame.access(4);
+        Assert.assertEquals("4,0,3", frame.toString());
+    }
+
+}

group24/315863321/src/main/java/com/johnChnia/coding2017/basic/LinkedList.java → group24/315863321/src/main/java/com/johnChnia/coding2017/basic/linklist/LinkedList.java

@@ -1,4 +1,6 @@
-package com.johnChnia.coding2017.basic;
+package com.johnChnia.coding2017.basic.linklist;
+
+import com.johnChnia.coding2017.basic.List;
 
 import java.util.NoSuchElementException;
 
@@ -345,7 +347,7 @@ public int[] getElements(LinkedList list) {
                 valueNode = valueNode.next;
                 indexOfArray++;
             } else {
-                mapNode = mapNode.next;
+                valueNode = valueNode.next;
             }
             indexOfList++;
         }

group24/315863321/src/test/java/com/johnChnia/coding2017/basic/ArrayListTest.java

@@ -54,7 +54,6 @@ public void testRemoveElementByIndex() {
             arrayList4.add(i);
         }
         Object removed = arrayList4.remove(4);
-        System.out.println(arrayList4);
         assertThat(removed, equalTo(4));
         assertThat(arrayList4.size(), equalTo(5));
     }

group24/315863321/src/test/java/com/johnChnia/coding2017/basic/LinkedListTest.java

@@ -2,7 +2,7 @@
 
 import org.junit.Before;
 import org.junit.Test;
-
+import com.johnChnia.coding2017.basic.linklist.LinkedList;
 import java.util.Arrays;
 
 import static org.hamcrest.CoreMatchers.containsString;