Map.java

public interface Map<K, V> {
    int size();
    boolean isEmpty();
    void clear();
    V put(K key, V value);
    V get(K key);
    V remove(K key);
    boolean containsKey(K key);
    boolean containsValue(V value);
    void traversal(Visitor<K, V> visitor);
    
    public static abstract class Visitor<K, V> {
        boolean stop;
        public abstract boolean visit(K key, V value);
    }
}

HashMap.java

@SuppressWarnings({"unchecked", "rawtypes"})
public class HashMap<K, V> implements Map<K, V> {
    private static final boolean RED = false;
    private static final boolean BLACK = true;
    private int size;
    private Node<K, V>[] table;
    private static final int DEFAULT_CAPACITY = 1 << 4;
    private static final float DEFAULT_LOAD_FACTOR = 0.75f;
    
    public HashMap() {
        table = new Node[DEFAULT_CAPACITY];
    }

    @Override
    public int size() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    @Override
    public void clear() {
        if (size == 0) return;
        size = 0;
        for (int i = 0; i < table.length; i++) {
            table[i] = null;
        }
    }

    @Override
    public V put(K key, V value) {
        resize();
        
        int index = index(key);
        // 取出index位置的红黑树根节点
        Node<K, V> root = table[index];
        if (root == null) {
            root = createNode(key, value, null);
            table[index] = root;
            size++;
            fixAfterPut(root);
            return null;
        }
        
        // 添加新的节点到红黑树上面
        Node<K, V> parent = root;
        Node<K, V> node = root;
        int cmp = 0;
        K k1 = key;
        int h1 = hash(k1);
        Node<K, V> result = null;
        boolean searched = false; // 是否已经搜索过这个key
        do {
            parent = node;
            K k2 = node.key;
            int h2 = node.hash;
            if (h1 > h2) {
                cmp = 1;
            } else if (h1 < h2) {
                cmp = -1;
            } else if (Objects.equals(k1, k2)) {
                cmp = 0;
            } else if (k1 != null && k2 != null 
                    && k1 instanceof Comparable
                    && k1.getClass() == k2.getClass()
                    && (cmp = ((Comparable)k1).compareTo(k2)) != 0) {
            } else if (searched) { // 已经扫描了
                cmp = System.identityHashCode(k1) - System.identityHashCode(k2);
            } else { // searched == false; 还没有扫描，然后再根据内存地址大小决定左右
                if ((node.left != null && (result = node(node.left, k1)) != null)
                        || (node.right != null && (result = node(node.right, k1)) != null)) {
                    // 已经存在这个key
                    node = result;
                    cmp = 0;
                } else { // 不存在这个key
                    searched = true;
                    cmp = System.identityHashCode(k1) - System.identityHashCode(k2);
                }
            }
            
            if (cmp > 0) {
                node = node.right;
            } else if (cmp < 0) {
                node = node.left;
            } else { // 相等
                V oldValue = node.value;
                node.key = key;
                node.value = value;
                node.hash = h1;
                return oldValue;
            }
        } while (node != null);

        // 看看插入到父节点的哪个位置
        Node<K, V> newNode = createNode(key, value, parent);
        if (cmp > 0) {
            parent.right = newNode;
        } else {
            parent.left = newNode;
        }
        size++;
        
        // 新添加节点之后的处理
        fixAfterPut(newNode);
        return null;
    }

    @Override
    public V get(K key) {
        Node<K, V> node = node(key);
        return node != null ? node.value : null;
    }

    @Override
    public V remove(K key) {
        return remove(node(key));
    }

    @Override
    public boolean containsKey(K key) {
        return node(key) != null;
    }

    @Override
    public boolean containsValue(V value) {
        if (size == 0) return false;
        Queue<Node<K, V>> queue = new LinkedList<>();
        for (int i = 0; i < table.length; i++) {
            if (table[i] == null) continue;
            
            queue.offer(table[i]);
            while (!queue.isEmpty()) {
                Node<K, V> node = queue.poll();
                if (Objects.equals(value, node.value)) return true;
                
                if (node.left != null) {
                    queue.offer(node.left);
                }
                if (node.right != null) {
                    queue.offer(node.right);
                }
            }
        }
        return false;
    }

    @Override
    public void traversal(Visitor<K, V> visitor) {
        if (size == 0 || visitor == null) return;
        
        Queue<Node<K, V>> queue = new LinkedList<>();
        for (int i = 0; i < table.length; i++) {
            if (table[i] == null) continue;
            
            queue.offer(table[i]);
            while (!queue.isEmpty()) {
                Node<K, V> node = queue.poll();
                if (visitor.visit(node.key, node.value)) return;
                
                if (node.left != null) {
                    queue.offer(node.left);
                }
                if (node.right != null) {
                    queue.offer(node.right);
                }
            }
        }
    }
    
    public void print() {
        if (size == 0) return;
        for (int i = 0; i < table.length; i++) {
            final Node<K, V> root = table[i];
            System.out.println("【index = " + i + "】");
            BinaryTrees.println(new BinaryTreeInfo() {
                @Override
                public Object string(Object node) {
                    return node;
                }
                
                @Override
                public Object root() {
                    return root;
                }
                
                @Override
                public Object right(Object node) {
                    return ((Node<K, V>)node).right;
                }
                
                @Override
                public Object left(Object node) {
                    return ((Node<K, V>)node).left;
                }
            });
            System.out.println("---------------------------------------------------");
        }
    }
    
    protected Node<K, V> createNode(K key, V value, Node<K, V> parent) {
        return new Node<>(key, value, parent);
    }
    
    protected void afterRemove(Node<K, V> willNode, Node<K, V> removedNode) { }
    
    private void resize() {
        // 装填因子 <= 0.75
        if (size / table.length <= DEFAULT_LOAD_FACTOR) return;
        
        Node<K, V>[] oldTable = table;
        table = new Node[oldTable.length << 1];

        Queue<Node<K, V>> queue = new LinkedList<>();
        for (int i = 0; i < oldTable.length; i++) {
            if (oldTable[i] == null) continue;
            
            queue.offer(oldTable[i]);
            while (!queue.isEmpty()) {
                Node<K, V> node = queue.poll();
                if (node.left != null) {
                    queue.offer(node.left);
                }
                if (node.right != null) {
                    queue.offer(node.right);
                }
                
                // 挪动代码得放到最后面
                moveNode(node);
            }
        }
    }
    
    private void moveNode(Node<K, V> newNode) {
        // 重置
        newNode.parent = null;
        newNode.left = null;
        newNode.right = null;
        newNode.color = RED;
        
        int index = index(newNode);
        // 取出index位置的红黑树根节点
        Node<K, V> root = table[index];
        if (root == null) {
            root = newNode;
            table[index] = root;
            fixAfterPut(root);
            return;
        }
        
        // 添加新的节点到红黑树上面
        Node<K, V> parent = root;
        Node<K, V> node = root;
        int cmp = 0;
        K k1 = newNode.key;
        int h1 = newNode.hash;
        do {
            parent = node;
            K k2 = node.key;
            int h2 = node.hash;
            if (h1 > h2) {
                cmp = 1;
            } else if (h1 < h2) {
                cmp = -1;
            } else if (k1 != null && k2 != null 
                    && k1 instanceof Comparable
                    && k1.getClass() == k2.getClass()
                    && (cmp = ((Comparable)k1).compareTo(k2)) != 0) {
            } else {
                cmp = System.identityHashCode(k1) - System.identityHashCode(k2);
            }
            
            if (cmp > 0) {
                node = node.right;
            } else if (cmp < 0) {
                node = node.left;
            }
        } while (node != null);

        // 看看插入到父节点的哪个位置
        newNode.parent = parent;
        if (cmp > 0) {
            parent.right = newNode;
        } else {
            parent.left = newNode;
        }
        
        // 新添加节点之后的处理
        fixAfterPut(newNode);
    }
    
    protected V remove(Node<K, V> node) {
        if (node == null) return null;
        
        Node<K, V> willNode = node;
        
        size--;
        
        V oldValue = node.value;
        
        if (node.hasTwoChildren()) { // 度为2的节点
            // 找到后继节点
            Node<K, V> s = successor(node);
            // 用后继节点的值覆盖度为2的节点的值
            node.key = s.key;
            node.value = s.value;
            node.hash = s.hash;
            // 删除后继节点
            node = s;
        }
        
        // 删除node节点（node的度必然是1或者0）
        Node<K, V> replacement = node.left != null ? node.left : node.right;
        int index = index(node);
        
        if (replacement != null) { // node是度为1的节点
            // 更改parent
            replacement.parent = node.parent;
            // 更改parent的left、right的指向
            if (node.parent == null) { // node是度为1的节点并且是根节点
                table[index] = replacement;
            } else if (node == node.parent.left) {
                node.parent.left = replacement;
            } else { // node == node.parent.right
                node.parent.right = replacement;
            }
            
            // 删除节点之后的处理
            fixAfterRemove(replacement);
        } else if (node.parent == null) { // node是叶子节点并且是根节点
            table[index] = null;
        } else { // node是叶子节点，但不是根节点
            if (node == node.parent.left) {
                node.parent.left = null;
            } else { // node == node.parent.right
                node.parent.right = null;
            }
            
            // 删除节点之后的处理
            fixAfterRemove(node);
        }
        
        // 交给子类去处理
        afterRemove(willNode, node);
        
        return oldValue;
    }
    
    private Node<K, V> successor(Node<K, V> node) {
        if (node == null) return null;
        
        // 前驱节点在左子树当中（right.left.left.left....）
        Node<K, V> p = node.right;
        if (p != null) {
            while (p.left != null) {
                p = p.left;
            }
            return p;
        }
        
        // 从父节点、祖父节点中寻找前驱节点
        while (node.parent != null && node == node.parent.right) {
            node = node.parent;
        }

        return node.parent;
    }
    
    private Node<K, V> node(K key) {
        Node<K, V> root = table[index(key)];
        return root == null ? null : node(root, key);
    }
    
    private Node<K, V> node(Node<K, V> node, K k1) {
        int h1 = hash(k1);
        // 存储查找结果
        Node<K, V> result = null;
        int cmp = 0;
        while (node != null) {
            K k2 = node.key;
            int h2 = node.hash;
            // 先比较哈希值
            if (h1 > h2) {
                node = node.right;
            } else if (h1 < h2) {
                node = node.left;
            } else if (Objects.equals(k1, k2)) {
                return node;
            } else if (k1 != null && k2 != null 
                    && k1 instanceof Comparable
                    && k1.getClass() == k2.getClass()
                    && (cmp = ((Comparable)k1).compareTo(k2)) != 0) {
                node = cmp > 0 ? node.right : node.left;
            } else if (node.right != null && (result = node(node.right, k1)) != null) { 
                return result;
            } else { // 只能往左边找
                node = node.left;
            }
        }
        return null;
    }
    
    /**
     * 根据key生成对应的索引（在桶数组中的位置）
     */
    private int index(K key) {
        return hash(key) & (table.length - 1);
    }
    
    private int hash(K key) {
        if (key == null) return 0;
        int hash = key.hashCode();
        return hash ^ (hash >>> 16);
    }
    
    private int index(Node<K, V> node) {
        return node.hash & (table.length - 1);
    }

    private void fixAfterRemove(Node<K, V> node) {
        // 如果删除的节点是红色
        // 或者 用以取代删除节点的子节点是红色
        if (isRed(node)) {
            black(node);
            return;
        }
        
        Node<K, V> parent = node.parent;
        if (parent == null) return;
        
        // 删除的是黑色叶子节点【下溢】
        // 判断被删除的node是左还是右
        boolean left = parent.left == null || node.isLeftChild();
        Node<K, V> sibling = left ? parent.right : parent.left;
        if (left) { // 被删除的节点在左边，兄弟节点在右边
            if (isRed(sibling)) { // 兄弟节点是红色
                black(sibling);
                red(parent);
                rotateLeft(parent);
                // 更换兄弟
                sibling = parent.right;
            }
            
            // 兄弟节点必然是黑色
            if (isBlack(sibling.left) && isBlack(sibling.right)) {
                // 兄弟节点没有1个红色子节点，父节点要向下跟兄弟节点合并
                boolean parentBlack = isBlack(parent);
                black(parent);
                red(sibling);
                if (parentBlack) {
                    fixAfterRemove(parent);
                }
            } else { // 兄弟节点至少有1个红色子节点，向兄弟节点借元素
                // 兄弟节点的左边是黑色，兄弟要先旋转
                if (isBlack(sibling.right)) {
                    rotateRight(sibling);
                    sibling = parent.right;
                }
                
                color(sibling, colorOf(parent));
                black(sibling.right);
                black(parent);
                rotateLeft(parent);
            }
        } else { // 被删除的节点在右边，兄弟节点在左边
            if (isRed(sibling)) { // 兄弟节点是红色
                black(sibling);
                red(parent);
                rotateRight(parent);
                // 更换兄弟
                sibling = parent.left;
            }
            
            // 兄弟节点必然是黑色
            if (isBlack(sibling.left) && isBlack(sibling.right)) {
                // 兄弟节点没有1个红色子节点，父节点要向下跟兄弟节点合并
                boolean parentBlack = isBlack(parent);
                black(parent);
                red(sibling);
                if (parentBlack) {
                    fixAfterRemove(parent);
                }
            } else { // 兄弟节点至少有1个红色子节点，向兄弟节点借元素
                // 兄弟节点的左边是黑色，兄弟要先旋转
                if (isBlack(sibling.left)) {
                    rotateLeft(sibling);
                    sibling = parent.left;
                }
                
                color(sibling, colorOf(parent));
                black(sibling.left);
                black(parent);
                rotateRight(parent);
            }
        }
    }

    private void fixAfterPut(Node<K, V> node) {
        Node<K, V> parent = node.parent;
        
        // 添加的是根节点 或者 上溢到达了根节点
        if (parent == null) {
            black(node);
            return;
        }
        
        // 如果父节点是黑色，直接返回
        if (isBlack(parent)) return;
        
        // 叔父节点
        Node<K, V> uncle = parent.sibling();
        // 祖父节点
        Node<K, V> grand = red(parent.parent);
        if (isRed(uncle)) { // 叔父节点是红色【B树节点上溢】
            black(parent);
            black(uncle);
            // 把祖父节点当做是新添加的节点
            fixAfterPut(grand);
            return;
        }
        
        // 叔父节点不是红色
        if (parent.isLeftChild()) { // L
            if (node.isLeftChild()) { // LL
                black(parent);
            } else { // LR
                black(node);
                rotateLeft(parent);
            }
            rotateRight(grand);
        } else { // R
            if (node.isLeftChild()) { // RL
                black(node);
                rotateRight(parent);
            } else { // RR
                black(parent);
            }
            rotateLeft(grand);
        }
    }
    
    private void rotateLeft(Node<K, V> grand) {
        Node<K, V> parent = grand.right;
        Node<K, V> child = parent.left;
        grand.right = child;
        parent.left = grand;
        afterRotate(grand, parent, child);
    }
    
    private void rotateRight(Node<K, V> grand) {
        Node<K, V> parent = grand.left;
        Node<K, V> child = parent.right;
        grand.left = child;
        parent.right = grand;
        afterRotate(grand, parent, child);
    }
    
    private void afterRotate(Node<K, V> grand, Node<K, V> parent, Node<K, V> child) {
        // 让parent称为子树的根节点
        parent.parent = grand.parent;
        if (grand.isLeftChild()) {
            grand.parent.left = parent;
        } else if (grand.isRightChild()) {
            grand.parent.right = parent;
        } else { // grand是root节点
            table[index(grand)] = parent;
        }
        
        // 更新child的parent
        if (child != null) {
            child.parent = grand;
        }
        
        // 更新grand的parent
        grand.parent = parent;
    }

    private Node<K, V> color(Node<K, V> node, boolean color) {
        if (node == null) return node;
        node.color = color;
        return node;
    }
    
    private Node<K, V> red(Node<K, V> node) {
        return color(node, RED);
    }
    
    private Node<K, V> black(Node<K, V> node) {
        return color(node, BLACK);
    }
    
    private boolean colorOf(Node<K, V> node) {
        return node == null ? BLACK : node.color;
    }
    
    private boolean isBlack(Node<K, V> node) {
        return colorOf(node) == BLACK;
    }
    
    private boolean isRed(Node<K, V> node) {
        return colorOf(node) == RED;
    }
    
    protected static class Node<K, V> {
        int hash;
        K key;
        V value;
        boolean color = RED;
        Node<K, V> left;
        Node<K, V> right;
        Node<K, V> parent;
        public Node(K key, V value, Node<K, V> parent) {
            this.key = key;
            int hash = key == null ? 0 : key.hashCode();
            this.hash = hash ^ (hash >>> 16);
            this.value = value;
            this.parent = parent;
        }
        
        public boolean hasTwoChildren() {
            return left != null && right != null;
        }
        
        public boolean isLeftChild() {
            return parent != null && this == parent.left;
        }
        
        public boolean isRightChild() {
            return parent != null && this == parent.right;
        }
        
        public Node<K, V> sibling() {
            if (isLeftChild()) {
                return parent.right;
            }
            
            if (isRightChild()) {
                return parent.left;
            }
            
            return null;
        }
        
        @Override
        public String toString() {
            return "Node_" + key + "_" + value;
        }
    }
}

LinkedHashMap.java

@SuppressWarnings({ "rawtypes", "unchecked" })
public class LinkedHashMap<K, V> extends HashMap<K, V> {
    private LinkedNode<K, V> first;
    private LinkedNode<K, V> last;
    
    @Override
    public void clear() {
        super.clear();
        first = null;
        last = null;
    }
    
    @Override
    public boolean containsValue(V value) {
        LinkedNode<K, V> node = first;
        while (node != null) {
            if (Objects.equals(value, node.value)) return true;
            node = node.next;
        }
        return false;
    }
    
    @Override
    public void traversal(Visitor<K, V> visitor) {
        if (visitor == null) return;
        LinkedNode<K, V> node = first;
        while (node != null) {
            if (visitor.visit(node.key, node.value)) return;
            node = node.next;
        }
    }
    
    @Override
    protected void afterRemove(Node<K, V> willNode, Node<K, V> removedNode) {
        LinkedNode<K, V> node1 = (LinkedNode<K, V>) willNode;
        LinkedNode<K, V> node2 = (LinkedNode<K, V>) removedNode;
        
        if (node1 != node2) {
            // 交换linkedWillNode和linkedRemovedNode在链表中的位置
            // 交换prev
            LinkedNode<K, V> tmp = node1.prev;
            node1.prev = node2.prev;
            node2.prev = tmp;
            if (node1.prev == null) {
                first = node1;
            } else {
                node1.prev.next = node1;
            }
            if (node2.prev == null) {
                first = node2;
            } else {
                node2.prev.next = node2;
            }
            
            // 交换next
            tmp = node1.next;
            node1.next = node2.next;
            node2.next = tmp;
            if (node1.next == null) {
                last = node1;
            } else {
                node1.next.prev = node1;
            }
            if (node2.next == null) {
                last = node2;
            } else {
                node2.next.prev = node2;
            }
        }
        
        LinkedNode<K, V> prev = node2.prev;
        LinkedNode<K, V> next = node2.next;
        if (prev == null) {
            first = next;
        } else {
            prev.next = next;
        }
        
        if (next == null) {
            last = prev;
        } else {
            next.prev = prev;
        }
    }
    
    @Override
    protected Node<K, V> createNode(K key, V value, Node<K, V> parent) {
        LinkedNode node = new LinkedNode(key, value, parent);
        if (first == null) {
            first = last = node;
        } else {
            last.next = node;
            node.prev = last;
            last = node;
        }
        return node;
    }
    
    private static class LinkedNode<K, V> extends Node<K, V> {
        LinkedNode<K, V> prev;
        LinkedNode<K, V> next;
        public LinkedNode(K key, V value, Node<K, V> parent) {
            super(key, value, parent);
        }
    }
}