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Map：接口，定义了map的基本操作
AbstractMap：抽象类，提供了Map的基本实现
/*https://blog.csdn.net/chenXingXu/article/details/79432585*/
/*http://www.cnblogs.com/skywang12345/p/3310835.html*/
/*https://blog.csdn.net/juewang_love/article/details/52674915*/
public class HashMap extends AbstractMap
implements Map, Cloneable, Serializable {
/*序列化ID*/
private static final long serialVersionUID = 362498820763181265L;
/*默认的初始容量*/
static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16
/*最大容量，如果指定的容量大于这个值，将会使用这个值进行替换，必须是小于2的30次方*/
static final int MAXIMUM_CAPACITY = 1 << 30;
/*默认的加载因子*/
static final float DEFAULT_LOAD_FACTOR = 0.75f;
/*阀值，当链表的长度大于这个值时，自动转换成红黑树*/
static final int TREEIFY_THRESHOLD = 8;
/*当红黑树的大小小于这个值的时候，自动转换成链表*/
static final int UNTREEIFY_THRESHOLD = 6;
/*
https://www.imooc.com/article/24532?block_id=tuijian_wz
这个字段决定了当hash表的至少大小为多少时，链表才能进行树化。这个设计时合理的，
因为当hash表的大小很小时，这时候表所需的空间还不多，可以牺牲空间减少时间，
所以这个情况下 当存储的节点过多时，最好的办法是调整表的大小，使其增大，
而不是将链表树化。
**/
static final int MIN_TREEIFY_CAPACITY = 64;
/*链表元素的基本节点*/
static class Node implements Map.Entry {
final int hash; // 哈希值，HashMap根据该值确定记录的位置
final K key;
V value;
Node next;// 链表下一个节点
Node(int hash, K key, V value, Node next) {
this.hash = hash;
this.key = key;
this.value = value;
this.next = next;
}
public final K getKey() { return key; }
public final V getValue() { return value; }
public final String toString() { return key + "=" + value; }
/*获取key和value的哈希值取 ^ */
public final int hashCode() {
return Objects.hashCode(key) ^ Objects.hashCode(value);
}
/*设置新的值*/
public final V setValue(V newValue) {
V oldValue = value;
value = newValue;
return oldValue;//返回旧的值
}
/*重写equals方法*/
public final boolean equals(Object o) {
if (o == this)
return true;
if (o instanceof Map.Entry) {
Map.Entry e = (Map.Entry)o;
/*当key和value都相等时，就相等*/
if (Objects.equals(key, e.getKey()) &&
Objects.equals(value, e.getValue()))
return true;
}
return false;
}
}
/* ---------------- Static utilities -------------- */
/*https://blog.csdn.net/qazwyc/article/details/76686915*/
/*使key的hashcode()高16位不变，低16位与高16位异或*/
static final int hash(Object key) {
int h;
return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
}
/*如果x是一个实现了comparable接口则返回x的class对象，反之返回null*/
static Class comparableClassFor(Object x) {
if (x instanceof Comparable) {/*如果实现Comparable接口*/
Class c; Type[] ts, as; Type t; ParameterizedType p;
if ((c = x.getClass()) == String.class) // bypass checks
return c;
if ((ts = c.getGenericInterfaces()) != null) {
for (int i = 0; i < ts.length; ++i) {
/*判断结果类似于String类型的接口实现*/
/*https://blog.csdn.net/qpzkobe/article/details/79533237*/
//getRawType()返回一个type类型代表的类或借口，如Collection会返回Collection
//getActualTypeArguments 返回一个type[] 如Collection会返回String
if (((t = ts[i]) instanceof ParameterizedType) &&
((p = (ParameterizedType)t).getRawType() ==
Comparable.class) &&
(as = p.getActualTypeArguments()) != null &&
as.length == 1 && as[0] == c) // type arg is c
return c;/*返回Collection的E类型*/
}
}
}
return null;
}
/*如果x所属的类是kc，返回k.compareTo(x)的比较结果
* 如果x为空，或者其所属的类不是kc，返回0*/
@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
static int compareComparables(Class kc, Object k, Object x) {
/*https://www.cnblogs.com/zjfjava/p/5996666.html*/
/* ||的优先级大于？ */
return (x == null || x.getClass() != kc ? 0 :
((Comparable)k).compareTo(x));
}
/*返回最近的不小于输入参数的2的整数次幂*/
/*https://blog.csdn.net/qazwyc/article/details/76686915*/
static final int tableSizeFor(int cap) {
/*cap-1再赋值给n的目的是令找到的目标值大于或等于原值。
如果cap本身是2的幂，如8（1000(2)），不对它减1而直接操作，将得到16*/
int n = cap - 1;
n |= n >>> 1;
n |= n >>> 2;
n |= n >>> 4;
n |= n >>> 8;
n |= n >>> 16;
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
}
/* ---------------- Fields -------------- */
// 存储元素的数组，总是2的幂
transient Node[] table;
//缓存的entryset()
transient Set> entrySet;
/*包含的键值对数*/
transient int size;
/*修改次数*/
transient int modCount;
/* 临界值 当实际大小(容量*填充因子)超过临界值时，会进行扩容，默认12*/
int threshold;
/*加载因子*/
final float loadFactor;
/* ---------------- Public operations -------------- */
/*构造函数，指定初始容量，指定加载因子*/
public HashMap(int initialCapacity, float loadFactor) {
if (initialCapacity < 0)
throw new IllegalArgumentException("Illegal initial capacity: " +
initialCapacity);
if (initialCapacity > MAXIMUM_CAPACITY)
initialCapacity = MAXIMUM_CAPACITY;
if (loadFactor <= 0 || Float.isNaN(loadFactor))/*加载因子必须大于0.0*/
throw new IllegalArgumentException("Illegal load factor: " +
loadFactor);
this.loadFactor = loadFactor;
this.threshold = tableSizeFor(initialCapacity);
}
/*构造方法，指定容量*/
public HashMap(int initialCapacity) {
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
/*默认构造函数*/
public HashMap() {
this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
}
/*构造函数，指定初始化map*/
public HashMap(Map m) {
this.loadFactor = DEFAULT_LOAD_FACTOR;
putMapEntries(m, false);
}
/*evict是false时，表示初始化*/
final void putMapEntries(Map m, boolean evict) {
int s = m.size();
if (s > 0) {
if (table == null) { // pre-size/*未初始化*/
float ft = ((float)s / loadFactor) + 1.0F;/*计算所需容量*/
int t = ((ft < (float)MAXIMUM_CAPACITY) ?
(int)ft : MAXIMUM_CAPACITY);
if (t > threshold)
threshold = tableSizeFor(t);/*计算table大小，即table的最大容量*/
}
else if (s > threshold)
resize();/*如果table容量不够，就进行扩容*/
for (Map.Entry e : m.entrySet()) {
K key = e.getKey();
V value = e.getValue();
/*添加元素*/
putVal(hash(key), key, value, false, evict);
}
}
}
/*获取map数*/
public int size() {
return size;
}
/*判断是否为空*/
public boolean isEmpty() {
return size == 0;
}
/*获取指定key，对应的value*/
public V get(Object key) {
Node e;
return (e = getNode(hash(key), key)) == null ? null : e.value;
}
/*根据hash，key获取对应的Node*/
final Node getNode(int hash, Object key) {
Node[] tab; Node first, e; int n; K k;
if ((tab = table) != null && (n = tab.length) > 0 &&
(first = tab[(n - 1) & hash]) != null) {
if (first.hash == hash && // always check first node
((k = first.key) == key || (key != null && key.equals(k))))/*判断是否是第一个*/
return first;
if ((e = first.next) != null) {/*进入链表*/
if (first instanceof TreeNode)/*如果是红黑树结构*/
return ((TreeNode)first).getTreeNode(hash, key);
do {/*如果是链表结构*/
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k))))
return e;
} while ((e = e.next) != null);
}
}
return null;
}
/*判断是否包含指定key*/
public boolean containsKey(Object key) {
return getNode(hash(key), key) != null;
}
/*添加数据*/
public V put(K key, V value) {
return putVal(hash(key), key, value, false, true);
}
/*用来添加元素*/
final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
boolean evict) {
Node[] tab; Node p; int n, i;
if ((tab = table) == null || (n = tab.length) == 0)/*如果table未初始化*/
n = (tab = resize()).length;
/*需判断是否存在Hash冲突：*/
if ((p = tab[i = (n - 1) & hash]) == null)/*计算table中的位置*/
tab[i] = newNode(hash, key, value, null);/*若不存在（即当前table[i] == null），则直接在该数组位置新建节点，插入完毕*/
else {/*代表存在Hash冲突，即当前存储位置已存在节点，则依次往下判断*/
Node e; K k;
if (p.hash == hash &&
((k = p.key) == key || (key != null && key.equals(k))))/*判断当前位置是否是同一个元素*/
e = p;
else if (p instanceof TreeNode)/*是否需要插入tree*/
e = ((TreeNode)p).putTreeVal(this, tab, hash, key, value);
else {/*插入链表 */
for (int binCount = 0; ; ++binCount) {
if ((e = p.next) == null) {
/*表示已到表尾也没有找到key值相同节点，则新建节点 链表尾插入节点*/
p.next = newNode(hash, key, value, null);
if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st
/* 插入节点后，若链表节点>数阈值，则将链表转换为红黑树*/
treeifyBin(tab, hash);
break;
}
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k))))/*判断当前位置是否是同一个元素*/
break;
p = e;
}
}
/*发现key已存在，直接用新value 覆盖 旧value & 返回旧value*/
if (e != null) { // existing mapping for key
V oldValue = e.value;
if (!onlyIfAbsent || oldValue == null)
e.value = value;
afterNodeAccess(e);/*更新旧的值，没有实现*/
return oldValue;
}
}
++modCount;/*更新修改次数*/
if (++size > threshold)
resize();
afterNodeInsertion(evict);/*插入新的值，没有实现*/
return null;
}
/*初始化哈希表 ，当前数组容量过小，需扩容*/
final Node[] resize() {
Node[] oldTab = table;
int oldCap = (oldTab == null) ? 0 : oldTab.length;
int oldThr = threshold;
int newCap, newThr = 0;
if (oldCap > 0) {/*扩容*/
if (oldCap >= MAXIMUM_CAPACITY) {/*如果容量大于最大容量*/
threshold = Integer.MAX_VALUE;/*设置为最大的容量*/
return oldTab;
}
else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&/*扩容2倍*/
oldCap >= DEFAULT_INITIAL_CAPACITY)
newThr = oldThr << 1; // double threshold /*临界值2倍*/
}
else if (oldThr > 0) // initial capacity was placed in threshold
/*如果原来没有保存数据*/
newCap = oldThr;
else { // zero initial threshold signifies using defaults
/*如果没有初始化*/
newCap = DEFAULT_INITIAL_CAPACITY;
newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY);
}
if (newThr == 0) {/*重新设置临界值*/
float ft = (float)newCap * loadFactor;
/* && 的优先级大于？ */
newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
(int)ft : Integer.MAX_VALUE);
}
threshold = newThr;
@SuppressWarnings({"rawtypes","unchecked"})
Node[] newTab = (Node[])new Node[newCap];/*初始化table*/
table = newTab;
if (oldTab != null) {
for (int j = 0; j < oldCap; ++j) {/*把老table保存的数据保存到新创建的table*/
Node e;
if ((e = oldTab[j]) != null) {/*遍历table*/
oldTab[j] = null;
if (e.next == null)/*没有链表，没有红黑树*/
newTab[e.hash & (newCap - 1)] = e;
else if (e instanceof TreeNode)/*红黑树*/
((TreeNode)e).split(this, newTab, j, oldCap);
else { // preserve order/*链表*/
Node loHead = null, loTail = null;
Node hiHead = null, hiTail = null;
Node next;
do {
next = e.next;
if ((e.hash & oldCap) == 0) {
if (loTail == null)
loHead = e;
else
loTail.next = e;
loTail = e;
}
else {
if (hiTail == null)
hiHead = e;
else
hiTail.next = e;
hiTail = e;
}
} while ((e = next) != null);
if (loTail != null) {
loTail.next = null;
newTab[j] = loHead;
}
if (hiTail != null) {
hiTail.next = null;
newTab[j + oldCap] = hiHead;
}
}
}
}
}
return newTab;/*返回新的table*/
}
/*https://blog.csdn.net/Super_Me_Jason/article/details/79729153*/
/*
链表长度超过TREEIFY_THRESHOLD(默认为8)时,会调用本方法,
本方法会判断HashMap的长度,如果小于MIN_TREEIFY_CAPACITY(默认为64),
则进行扩容,否则将链表转换为TreeNode链,最后调用treeify方法生成红黑树
*/
final void treeifyBin(Node[] tab, int hash) {
int n, index; Node e;
if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)/*如果table的length小于64*/
resize();/*对table扩容*/
else if ((e = tab[index = (n - 1) & hash]) != null) {
TreeNode hd = null, tl = null;
do {
TreeNode p = replacementTreeNode(e, null);/*把链表结点转换成树节点*/
if (tl == null)
hd = p;
else {/*还是搞成链表*/
p.prev = tl;
tl.next = p;
}
tl = p;
} while ((e = e.next) != null);
if ((tab[index] = hd) != null)
hd.treeify(tab);/*将table[index]变成二叉树*/
}
}
/*将m中的元素全部添加*/
public void putAll(Map m) {
putMapEntries(m, true);
}
/*根据key删除元素*/
public V remove(Object key) {
Node e;
return (e = removeNode(hash(key), key, null, false, true)) == null ?
null : e.value;
}
/*删除元素*/
final Node removeNode(int hash, Object key, Object value,
boolean matchValue, boolean movable) {
Node[] tab; Node p; int n, index;
if ((tab = table) != null && (n = tab.length) > 0 &&
(p = tab[index = (n - 1) & hash]) != null) {
Node node = null, e; K k; V v;
if (p.hash == hash &&
((k = p.key) == key || (key != null && key.equals(k))))/*table中删除*/
node = p;
else if ((e = p.next) != null) {
if (p instanceof TreeNode)/*树中删除*/
node = ((TreeNode)p).getTreeNode(hash, key);
else {
do {/*链表中删除*/
if (e.hash == hash &&
((k = e.key) == key ||
(key != null && key.equals(k)))) {
node = e;
break;
}
p = e;
} while ((e = e.next) != null);
}
}
if (node != null && (!matchValue || (v = node.value) == value ||
(value != null && value.equals(v)))) {
if (node instanceof TreeNode)/*书中删除*/
((TreeNode)node).removeTreeNode(this, tab, movable);
else if (node == p)
tab[index] = node.next;/*table删除*/
else
p.next = node.next;/*链表中删除*/
++modCount;
--size;
afterNodeRemoval(node);
return node;
}
}
return null;
}
/*清除map*/
public void clear() {
Node[] tab;
modCount++;
if ((tab = table) != null && size > 0) {
size = 0;
for (int i = 0; i < tab.length; ++i)
tab[i] = null;
}
}
/*判断是否包含value*/
public boolean containsValue(Object value) {
Node[] tab; V v;
if ((tab = table) != null && size > 0) {
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next) {
if ((v = e.value) == value ||
(value != null && value.equals(v)))
return true;
}
}
}
return false;
}
/*获取KeySpliterator，没有重复*/
public Set keySet() {
Set ks = keySet;
if (ks == null) {
ks = new KeySet();
keySet = ks;
}
return ks;
}
/*keySet*/
final class KeySet extends AbstractSet {
public final int size() { return size; }
public final void clear() { HashMap.this.clear(); }
public final Iterator iterator() { return new KeyIterator(); }
public final boolean contains(Object o) { return containsKey(o); }
public final boolean remove(Object key) {
return removeNode(hash(key), key, null, false, true) != null;
}
public final Spliterator spliterator() {
return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0);
}
public final void forEach(Consumer action) {
Node[] tab;
if (action == null)
throw new NullPointerException();
if (size > 0 && (tab = table) != null) {
int mc = modCount;
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next)
action.accept(e.key);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
}
/*获取ValueSpliterator，可能会有重复*/
public Collection values() {
Collection vs = values;
if (vs == null) {
vs = new Values();
values = vs;
}
return vs;
}
/*values*/
final class Values extends AbstractCollection {
public final int size() { return size; }
public final void clear() { HashMap.this.clear(); }
public final Iterator iterator() { return new ValueIterator(); }
public final boolean contains(Object o) { return containsValue(o); }
public final Spliterator spliterator() {
return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
}
public final void forEach(Consumer action) {
Node[] tab;
if (action == null)
throw new NullPointerException();
if (size > 0 && (tab = table) != null) {
int mc = modCount;
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next)
action.accept(e.value);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
}
/*获取EntryIterator*/
public Set> entrySet() {
Set> es;
return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
}
/*EntrySet*/
final class EntrySet extends AbstractSet> {
public final int size() { return size; }
public final void clear() { HashMap.this.clear(); }
public final Iterator> iterator() {
return new EntryIterator();
}
public final boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry e = (Map.Entry) o;
Object key = e.getKey();
Node candidate = getNode(hash(key), key);
return candidate != null && candidate.equals(e);
}
public final boolean remove(Object o) {
if (o instanceof Map.Entry) {
Map.Entry e = (Map.Entry) o;
Object key = e.getKey();
Object value = e.getValue();
return removeNode(hash(key), key, value, true, true) != null;
}
return false;
}
public final Spliterator> spliterator() {
return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
}
public final void forEach(Consumer> action) {
Node[] tab;
if (action == null)
throw new NullPointerException();
if (size > 0 && (tab = table) != null) {
int mc = modCount;
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next)
action.accept(e);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
}
// Overrides of JDK8 Map extension methods
/*如果没有就去默认值*/
@Override
public V getOrDefault(Object key, V defaultValue) {
Node e;
return (e = getNode(hash(key), key)) == null ? defaultValue : e.value;
}
/*如果没有添加*/
@Override
public V putIfAbsent(K key, V value) {
return putVal(hash(key), key, value, true, true);
}
/*删除指定的元素*/
@Override
public boolean remove(Object key, Object value) {
return removeNode(hash(key), key, value, true, true) != null;
}
/*替换指定的value*/
@Override
public boolean replace(K key, V oldValue, V newValue) {
Node e; V v;
if ((e = getNode(hash(key), key)) != null &&
((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) {
e.value = newValue;
afterNodeAccess(e);
return true;
}
return false;
}
/*替换value*/
@Override
public V replace(K key, V value) {
Node e;
if ((e = getNode(hash(key), key)) != null) {
V oldValue = e.value;
e.value = value;
afterNodeAccess(e);
return oldValue;
}
return null;
}
/*http://developer.51cto.com/art/201404/435216.htm*/
/*
* Map接口的实现类如HashMap,ConcurrentHashMap,HashTable等继承了此方法，
* 通过此方法可以构建JAVA本地缓存，降低程序的计算量，程序的复杂度，使代码简洁，易懂。
* */
@Override
public V computeIfAbsent(K key,
Function mappingFunction) {
if (mappingFunction == null)
throw new NullPointerException();
int hash = hash(key);
Node[] tab; Node first; int n, i;
int binCount = 0;
TreeNode t = null;
Node old = null;
if (size > threshold || (tab = table) == null ||
(n = tab.length) == 0)
n = (tab = resize()).length;
if ((first = tab[i = (n - 1) & hash]) != null) {
if (first instanceof TreeNode)
old = (t = (TreeNode)first).getTreeNode(hash, key);
else {
Node e = first; K k;
do {
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k)))) {
old = e;
break;
}
++binCount;
} while ((e = e.next) != null);
}
V oldValue;
if (old != null && (oldValue = old.value) != null) {
afterNodeAccess(old);
return oldValue;
}
}
V v = mappingFunction.apply(key);
if (v == null) {
return null;
} else if (old != null) {
old.value = v;
afterNodeAccess(old);
return v;
}
else if (t != null)
t.putTreeVal(this, tab, hash, key, v);
else {
tab[i] = newNode(hash, key, v, first);
if (binCount >= TREEIFY_THRESHOLD - 1)
treeifyBin(tab, hash);
}
++modCount;
++size;
afterNodeInsertion(true);
return v;
}
public V computeIfPresent(K key,
BiFunction remappingFunction) {
if (remappingFunction == null)
throw new NullPointerException();
Node e; V oldValue;
int hash = hash(key);
if ((e = getNode(hash, key)) != null &&
(oldValue = e.value) != null) {
V v = remappingFunction.apply(key, oldValue);
if (v != null) {
e.value = v;
afterNodeAccess(e);
return v;
}
else
removeNode(hash, key, null, false, true);
}
return null;
}
@Override
public V compute(K key,
BiFunction remappingFunction) {
if (remappingFunction == null)
throw new NullPointerException();
int hash = hash(key);
Node[] tab; Node first; int n, i;
int binCount = 0;
TreeNode t = null;
Node old = null;
if (size > threshold || (tab = table) == null ||
(n = tab.length) == 0)
n = (tab = resize()).length;
if ((first = tab[i = (n - 1) & hash]) != null) {
if (first instanceof TreeNode)
old = (t = (TreeNode)first).getTreeNode(hash, key);
else {
Node e = first; K k;
do {
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k)))) {
old = e;
break;
}
++binCount;
} while ((e = e.next) != null);
}
}
V oldValue = (old == null) ? null : old.value;
V v = remappingFunction.apply(key, oldValue);
if (old != null) {
if (v != null) {
old.value = v;
afterNodeAccess(old);
}
else
removeNode(hash, key, null, false, true);
}
else if (v != null) {
if (t != null)
t.putTreeVal(this, tab, hash, key, v);
else {
tab[i] = newNode(hash, key, v, first);
if (binCount >= TREEIFY_THRESHOLD - 1)
treeifyBin(tab, hash);
}
++modCount;
++size;
afterNodeInsertion(true);
}
return v;
}
@Override
public V merge(K key, V value,
BiFunction remappingFunction) {
if (value == null)
throw new NullPointerException();
if (remappingFunction == null)
throw new NullPointerException();
int hash = hash(key);
Node[] tab; Node first; int n, i;
int binCount = 0;
TreeNode t = null;
Node old = null;
if (size > threshold || (tab = table) == null ||
(n = tab.length) == 0)
n = (tab = resize()).length;
if ((first = tab[i = (n - 1) & hash]) != null) {
if (first instanceof TreeNode)
old = (t = (TreeNode)first).getTreeNode(hash, key);
else {
Node e = first; K k;
do {
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k)))) {
old = e;
break;
}
++binCount;
} while ((e = e.next) != null);
}
}
if (old != null) {
V v;
if (old.value != null)
v = remappingFunction.apply(old.value, value);
else
v = value;
if (v != null) {
old.value = v;
afterNodeAccess(old);
}
else
removeNode(hash, key, null, false, true);
return v;
}
if (value != null) {
if (t != null)
t.putTreeVal(this, tab, hash, key, value);
else {
tab[i] = newNode(hash, key, value, first);
if (binCount >= TREEIFY_THRESHOLD - 1)
treeifyBin(tab, hash);
}
++modCount;
++size;
afterNodeInsertion(true);
}
return value;
}
@Override
public void forEach(BiConsumer action) {
Node[] tab;
if (action == null)
throw new NullPointerException();
if (size > 0 && (tab = table) != null) {
int mc = modCount;
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next)
action.accept(e.key, e.value);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
@Override
public void replaceAll(BiFunction function) {
Node[] tab;
if (function == null)
throw new NullPointerException();
if (size > 0 && (tab = table) != null) {
int mc = modCount;
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next) {
e.value = function.apply(e.key, e.value);
}
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
/* ------------------------------------------------------------ */
// Cloning and serialization
/*重写clone*/
/*https://blog.csdn.net/wangbiao007/article/details/52625099*/
@SuppressWarnings("unchecked")
@Override
public Object clone() {
HashMap result;
try {
result = (HashMap)super.clone();
} catch (CloneNotSupportedException e) {
// this shouldn't happen, since we are Cloneable
throw new InternalError(e);
}
result.reinitialize();
result.putMapEntries(this, false);
return result;
}
// These methods are also used when serializing HashSets
/*负载因子*/
final float loadFactor() { return loadFactor; }
/*容量*/
final int capacity() {
return (table != null) ? table.length :
(threshold > 0) ? threshold :
DEFAULT_INITIAL_CAPACITY;
}
/*重写序列化方法*/
private void writeObject(java.io.ObjectOutputStream s)
throws IOException {
int buckets = capacity();
// Write out the threshold, loadfactor, and any hidden stuff
s.defaultWriteObject();
s.writeInt(buckets);
s.writeInt(size);
internalWriteEntries(s);
}
/*反序列化方法*/
private void readObject(java.io.ObjectInputStream s)
throws IOException, ClassNotFoundException {
// Read in the threshold (ignored), loadfactor, and any hidden stuff
s.defaultReadObject();
reinitialize();
if (loadFactor <= 0 || Float.isNaN(loadFactor))
throw new InvalidObjectException("Illegal load factor: " +
loadFactor);
s.readInt(); // Read and ignore number of buckets
int mappings = s.readInt(); // Read number of mappings (size)
if (mappings < 0)
throw new InvalidObjectException("Illegal mappings count: " +
mappings);
else if (mappings > 0) { // (if zero, use defaults)
// Size the table using given load factor only if within
// range of 0.25...4.0
float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
float fc = (float)mappings / lf + 1.0f;
int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
DEFAULT_INITIAL_CAPACITY :
(fc >= MAXIMUM_CAPACITY) ?
MAXIMUM_CAPACITY :
tableSizeFor((int)fc));
float ft = (float)cap * lf;
threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
(int)ft : Integer.MAX_VALUE);
@SuppressWarnings({"rawtypes","unchecked"})
Node[] tab = (Node[])new Node[cap];
table = tab;
// Read the keys and values, and put the mappings in the HashMap
for (int i = 0; i < mappings; i++) {
@SuppressWarnings("unchecked")
K key = (K) s.readObject();
@SuppressWarnings("unchecked")
V value = (V) s.readObject();
putVal(hash(key), key, value, false, false);
}
}
}
/* ------------------------------------------------------------ */
// iterators
/*迭代器*/
abstract class HashIterator {
Node next; // next entry to return
Node current; // current entry
int expectedModCount; // for fast-fail
int index; // current slot
HashIterator() {
expectedModCount = modCount;
Node[] t = table;
current = next = null;
index = 0;
if (t != null && size > 0) { // advance to first entry
do {} while (index < t.length && (next = t[index++]) == null);
}
}
public final boolean hasNext() {
return next != null;
}
final Node nextNode() {
Node[] t;
Node e = next;
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
if (e == null)
throw new NoSuchElementException();
if ((next = (current = e).next) == null && (t = table) != null) {
do {} while (index < t.length && (next = t[index++]) == null);
}
return e;
}
public final void remove() {
Node p = current;
if (p == null)
throw new IllegalStateException();
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
current = null;
K key = p.key;
removeNode(hash(key), key, null, false, false);
expectedModCount = modCount;
}
}
/*key迭代器*/
final class KeyIterator extends HashIterator
implements Iterator {
public final K next() { return nextNode().key; }
}
/*value迭代器*/
final class ValueIterator extends HashIterator
implements Iterator {
public final V next() { return nextNode().value; }
}
/*entry迭代器*/
final class EntryIterator extends HashIterator
implements Iterator> {
public final Map.Entry next() { return nextNode(); }
}
/* ------------------------------------------------------------ */
// spliterators
/*分段迭代器*/
static class HashMapSpliterator {
final HashMap map;
Node current; // current node
int index; // current index, modified on advance/split
int fence; // one past last index
int est; // size estimate
int expectedModCount; // for comodification checks
HashMapSpliterator(HashMap m, int origin,
int fence, int est,
int expectedModCount) {
this.map = m;
this.index = origin;
this.fence = fence;
this.est = est;
this.expectedModCount = expectedModCount;
}
final int getFence() { // initialize fence and size on first use
int hi;
if ((hi = fence) < 0) {
HashMap m = map;
est = m.size;
expectedModCount = m.modCount;
Node[] tab = m.table;
hi = fence = (tab == null) ? 0 : tab.length;
}
return hi;
}
public final long estimateSize() {
getFence(); // force init
return (long) est;
}
}
static final class KeySpliterator
extends HashMapSpliterator
implements Spliterator {
KeySpliterator(HashMap m, int origin, int fence, int est,
int expectedModCount) {
super(m, origin, fence, est, expectedModCount);
}
public KeySpliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid || current != null) ? null :
new KeySpliterator<>(map, lo, index = mid, est >>>= 1,
expectedModCount);
}
public void forEachRemaining(Consumer action) {
int i, hi, mc;
if (action == null)
throw new NullPointerException();
HashMap m = map;
Node[] tab = m.table;
if ((hi = fence) < 0) {
mc = expectedModCount = m.modCount;
hi = fence = (tab == null) ? 0 : tab.length;
}
else
mc = expectedModCount;
if (tab != null && tab.length >= hi &&
(i = index) >= 0 && (i < (index = hi) || current != null)) {
Node p = current;
current = null;
do {
if (p == null)
p = tab[i++];
else {
action.accept(p.key);
p = p.next;
}
} while (p != null || i < hi);
if (m.modCount != mc)
throw new ConcurrentModificationException();
}
}
public boolean tryAdvance(Consumer action) {
int hi;
if (action == null)
throw new NullPointerException();
Node[] tab = map.table;
if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
while (current != null || index < hi) {
if (current == null)
current = tab[index++];
else {
K k = current.key;
current = current.next;
action.accept(k);
if (map.modCount != expectedModCount)
throw new ConcurrentModificationException();
return true;
}
}
}
return false;
}
public int characteristics() {
return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
Spliterator.DISTINCT;
}
}
static final class ValueSpliterator
extends HashMapSpliterator
implements Spliterator {
ValueSpliterator(HashMap m, int origin, int fence, int est,
int expectedModCount) {
super(m, origin, fence, est, expectedModCount);
}
public ValueSpliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid || current != null) ? null :
new ValueSpliterator<>(map, lo, index = mid, est >>>= 1,
expectedModCount);
}
public void forEachRemaining(Consumer action) {
int i, hi, mc;
if (action == null)
throw new NullPointerException();
HashMap m = map;
Node[] tab = m.table;
if ((hi = fence) < 0) {
mc = expectedModCount = m.modCount;
hi = fence = (tab == null) ? 0 : tab.length;
}
else
mc = expectedModCount;
if (tab != null && tab.length >= hi &&
(i = index) >= 0 && (i < (index = hi) || current != null)) {
Node p = current;
current = null;
do {
if (p == null)
p = tab[i++];
else {
action.accept(p.value);
p = p.next;
}
} while (p != null || i < hi);
if (m.modCount != mc)
throw new ConcurrentModificationException();
}
}
public boolean tryAdvance(Consumer action) {
int hi;
if (action == null)
throw new NullPointerException();
Node[] tab = map.table;
if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
while (current != null || index < hi) {
if (current == null)
current = tab[index++];
else {
V v = current.value;
current = current.next;
action.accept(v);
if (map.modCount != expectedModCount)
throw new ConcurrentModificationException();
return true;
}
}
}
return false;
}
public int characteristics() {
return (fence < 0 || est == map.size ? Spliterator.SIZED : 0);
}
}
static final class EntrySpliterator
extends HashMapSpliterator
implements Spliterator> {
EntrySpliterator(HashMap m, int origin, int fence, int est,
int expectedModCount) {
super(m, origin, fence, est, expectedModCount);
}
public EntrySpliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid || current != null) ? null :
new EntrySpliterator<>(map, lo, index = mid, est >>>= 1,
expectedModCount);
}
public void forEachRemaining(Consumer> action) {
int i, hi, mc;
if (action == null)
throw new NullPointerException();
HashMap m = map;
Node[] tab = m.table;
if ((hi = fence) < 0) {
mc = expectedModCount = m.modCount;
hi = fence = (tab == null) ? 0 : tab.length;
}
else
mc = expectedModCount;
if (tab != null && tab.length >= hi &&
(i = index) >= 0 && (i < (index = hi) || current != null)) {
Node p = current;
current = null;
do {
if (p == null)
p = tab[i++];
else {
action.accept(p);
p = p.next;
}
} while (p != null || i < hi);
if (m.modCount != mc)
throw new ConcurrentModificationException();
}
}
public boolean tryAdvance(Consumer> action) {
int hi;
if (action == null)
throw new NullPointerException();
Node[] tab = map.table;
if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
while (current != null || index < hi) {
if (current == null)
current = tab[index++];
else {
Node e = current;
current = current.next;
action.accept(e);
if (map.modCount != expectedModCount)
throw new ConcurrentModificationException();
return true;
}
}
}
return false;
}
public int characteristics() {
return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
Spliterator.DISTINCT;
}
}
/* ------------------------------------------------------------ */
// LinkedHashMap support
/*
* The following package-protected methods are designed to be
* overridden by LinkedHashMap, but not by any other subclass.
* Nearly all other internal methods are also package-protected
* but are declared final, so can be used by LinkedHashMap, view
* classes, and HashSet.
*/
// Create a regular (non-tree) node
/*创建新的Node节点*/
Node newNode(int hash, K key, V value, Node next) {
return new Node<>(hash, key, value, next);
}
// For conversion from TreeNodes to plain nodes
Node replacementNode(Node p, Node next) {
return new Node<>(p.hash, p.key, p.value, next);
}
// Create a tree bin node
/*创建一个TreeNode*/
TreeNode newTreeNode(int hash, K key, V value, Node next) {
return new TreeNode<>(hash, key, value, next);
}
// For treeifyBin
TreeNode replacementTreeNode(Node p, Node next) {
return new TreeNode<>(p.hash, p.key, p.value, next);
}
/*重置*/
void reinitialize() {
table = null;
entrySet = null;
keySet = null;
values = null;
modCount = 0;
threshold = 0;
size = 0;
}
// Callbacks to allow LinkedHashMap post-actions
void afterNodeAccess(Node p) { }
void afterNodeInsertion(boolean evict) { }
void afterNodeRemoval(Node p) { }
// Called only from writeObject, to ensure compatible ordering.
void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
Node[] tab;
if (size > 0 && (tab = table) != null) {
for (int i = 0; i < tab.length; ++i) {
for (Node e = tab[i]; e != null; e = e.next) {
s.writeObject(e.key);
s.writeObject(e.value);
}
}
}
}
/* ------------------------------------------------------------ */
// Tree bins
/*二叉树节点*/
static final class TreeNode extends LinkedHashMap.Entry {
TreeNode parent; // red-black tree links
TreeNode left;
TreeNode right;
TreeNode prev; // needed to unlink next upon deletion
boolean red;
TreeNode(int hash, K key, V val, Node next) {
super(hash, key, val, next);
}
final TreeNode root() {
for (TreeNode r = this, p;;) {
if ((p = r.parent) == null)
return r;
r = p;
}
}
/*https://blog.csdn.net/weixin_42340670/article/details/80555860*/
/*这个方法里做的事情，就是保证树的根节点一定也要成为链表的首节点*/
static void moveRootToFront(Node[] tab, TreeNode root) {
int n;
if (root != null && tab != null && (n = tab.length) > 0) {
int index = (n - 1) & root.hash;
TreeNode first = (TreeNode)tab[index];
if (root != first) {/*如果table中的节点，和根节点不同*/
Node rn;
tab[index] = root;
/*树的结构不变，改变链表的结构，TreeNode既是一个红黑树结构，也是一个双链表结构*/
TreeNode rp = root.prev;
if ((rn = root.next) != null)
((TreeNode)rn).prev = rp;
if (rp != null)
rp.next = rn;
if (first != null)
first.prev = root;
root.next = first;
root.prev = null;
}
/*
* 这一步是防御性的编程
* 校验TreeNode对象是否满足红黑树和双链表的特性
* 如果这个方法校验不通过：可能是因为用户编程失误，破坏了结构（例如：并发场景下）；
* 也可能是TreeNode的实现有问题（这个是理论上的以防万一）；
*/
assert checkInvariants(root);
}
}
/*查找指定元素*/
final TreeNode find(int h, Object k, Class kc) {
TreeNode p = this;
do {
int ph, dir; K pk;
TreeNode pl = p.left, pr = p.right, q;
if ((ph = p.hash) > h)
p = pl;
else if (ph < h)
p = pr;
else if ((pk = p.key) == k || (k != null && k.equals(pk)))
return p;
else if (pl == null)
p = pr;
else if (pr == null)
p = pl;
else if ((kc != null ||
(kc = comparableClassFor(k)) != null) &&
(dir = compareComparables(kc, k, pk)) != 0)
p = (dir < 0) ? pl : pr;
else if ((q = pr.find(h, k, kc)) != null)
return q;
else
p = pl;
} while (p != null);
return null;
}
final TreeNode getTreeNode(int h, Object k) {
return ((parent != null) ? root() : this).find(h, k, null);
}
/*
* 用这个方法来比较两个对象，返回值要么大于0，要么小于0，不会为0
* 也就是说这一步一定能确定要插入的节点要么是树的左节点，要么是右节点，不然就无法继续满足二叉树结构了
*
* 先比较两个对象的类名，类名是字符串对象，就按字符串的比较规则
* 如果两个对象是同一个类型，那么调用本地方法为两个对象生成hashCode值，再进行比较，hashCode相等的话返回-1
*/
static int tieBreakOrder(Object a, Object b) {
int d;
if (a == null || b == null ||
(d = a.getClass().getName().
compareTo(b.getClass().getName())) == 0)
d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
-1 : 1);
return d;
}
/*实现该对象打头的链表转换为树结构*/
/*https://blog.csdn.net/weixin_42340670/article/details/80531795*/
final void treeify(Node[] tab) {
TreeNode root = null;/*定义树的根节点*/
for (TreeNode x = this, next; x != null; x = next) {/*遍历链表*/
next = (TreeNode)x.next;/*下一个节点*/
x.left = x.right = null;
if (root == null) {/*如果是第一个元素，初始化根节点*/
x.parent = null;
x.red = false;
root = x;
}
else {
K k = x.key;
int h = x.hash;
Class kc = null;
for (TreeNode p = root;;) {
int dir, ph;// dir 标识方向（左右）、ph标识当前树节点的hash值
K pk = p.key;
if ((ph = p.hash) > h)// 如果当前树节点hash值 大于 当前链表节点的hash值
dir = -1;
else if (ph < h)// 右侧
dir = 1;
/*
如果两个节点的key的hash值相等，那么还要通过其他方式再进行比较
如果当前链表节点的key实现了comparable接口，并且当前树节点和链表节点是相同Class的实例，那么通过comparable的方式再比较两者。
如果还是相等，最后再通过tieBreakOrder比较一次
*/
else if ((kc == null &&
(kc = comparableClassFor(k)) == null) ||
(dir = compareComparables(kc, k, pk)) == 0)/*相等，无法比较*/
dir = tieBreakOrder(k, pk);/*确定左右树*/
TreeNode xp = p;
/*
* 如果dir 小于等于0 ： 当前链表节点一定放置在当前树节点的左侧，
* 但不一定是该树节点的左孩子，也可能是左孩子的右孩子 或者 更深层次的节点。
* 如果dir 大于0 ： 当前链表节点一定放置在当前树节点的右侧，
* 但不一定是该树节点的右孩子，也可能是右孩子的左孩子 或者 更深层次的节点。
* 如果当前树节点不是叶子节点，那么最终会以当前树节点的左孩子或者右孩子 为 起始节点
* 再从GOTO1 处开始 重新寻找自己（当前链表节点）的位置
* 如果当前树节点就是叶子节点，那么根据dir的值，就可以把当前链表节点挂载到当前树节点的左或者右侧了。
* 挂载之后，还需要重新把树进行平衡。平衡之后，就可以针对下一个链表节点进行处理了。
*/
if ((p = (dir <= 0) ? p.left : p.right) == null) {
x.parent = xp;
if (dir <= 0)
xp.left = x;/*作为左孩子*/
else
xp.right = x;/*作为又孩子*/
root = balanceInsertion(root, x);/*重新平衡*/
break;
}
}
}
}
// 把所有的链表节点都遍历完之后，最终构造出来的树可能经历多个平衡操作，
// 根节点目前到底是链表的哪一个节点是不确定的
// 因为我们要基于树来做查找，所以就应该把 tab[N] 得到的对象一定根节点对象，
// 而目前只是链表的第一个节点对象，所以要做相应的处理。
moveRootToFront(tab, root);
}
/* 将二叉树转为链表*/
final Node untreeify(HashMap map) {
Node hd = null, tl = null;
for (Node q = this; q != null; q = q.next) {
Node p = map.replacementNode(q, null);
if (tl == null)
hd = p;
else
tl.next = p;
tl = p;
}
return hd;
}
/*树添加元素*/
final TreeNode putTreeVal(HashMap map, Node[] tab,
int h, K k, V v) {
Class kc = null;
boolean searched = false;
TreeNode root = (parent != null) ? root() : this;
for (TreeNode p = root;;) {
int dir, ph; K pk;
if ((ph = p.hash) > h)
dir = -1;
else if (ph < h)
dir = 1;
else if ((pk = p.key) == k || (k != null && k.equals(pk)))
return p;
else if ((kc == null &&
(kc = comparableClassFor(k)) == null) ||
(dir = compareComparables(kc, k, pk)) == 0) {
if (!searched) {
TreeNode q, ch;
searched = true;
if (((ch = p.left) != null &&
(q = ch.find(h, k, kc)) != null) ||
((ch = p.right) != null &&
(q = ch.find(h, k, kc)) != null))
return q;
}
dir = tieBreakOrder(k, pk);
}
TreeNode xp = p;
if ((p = (dir <= 0) ? p.left : p.right) == null) {
Node xpn = xp.next;
TreeNode x = map.newTreeNode(h, k, v, xpn);
if (dir <= 0)
xp.left = x;
else
xp.right = x;
xp.next = x;
x.parent = x.prev = xp;
if (xpn != null)
((TreeNode)xpn).prev = x;
moveRootToFront(tab, balanceInsertion(root, x));
return null;
}
}
}
/*树删除元素*/
final void removeTreeNode(HashMap map, Node[] tab,
boolean movable) {
int n;
if (tab == null || (n = tab.length) == 0)
return;
int index = (n - 1) & hash;
TreeNode first = (TreeNode)tab[index], root = first, rl;
TreeNode succ = (TreeNode)next, pred = prev;
if (pred == null)
tab[index] = first = succ;
else
pred.next = succ;
if (succ != null)
succ.prev = pred;
if (first == null)
return;
if (root.parent != null)
root = root.root();
if (root == null || root.right == null ||
(rl = root.left) == null || rl.left == null) {
tab[index] = first.untreeify(map); // too small
return;
}
TreeNode p = this, pl = left, pr = right, replacement;
if (pl != null && pr != null) {
TreeNode s = pr, sl;
while ((sl = s.left) != null) // find successor
s = sl;
boolean c = s.red; s.red = p.red; p.red = c; // swap colors
TreeNode sr = s.right;
TreeNode pp = p.parent;
if (s == pr) { // p was s's direct parent
p.parent = s;
s.right = p;
}
else {
TreeNode sp = s.parent;
if ((p.parent = sp) != null) {
if (s == sp.left)
sp.left = p;
else
sp.right = p;
}
if ((s.right = pr) != null)
pr.parent = s;
}
p.left = null;
if ((p.right = sr) != null)
sr.parent = p;
if ((s.left = pl) != null)
pl.parent = s;
if ((s.parent = pp) == null)
root = s;
else if (p == pp.left)
pp.left = s;
else
pp.right = s;
if (sr != null)
replacement = sr;
else
replacement = p;
}
else if (pl != null)
replacement = pl;
else if (pr != null)
replacement = pr;
else
replacement = p;
if (replacement != p) {
TreeNode pp = replacement.parent = p.parent;
if (pp == null)
root = replacement;
else if (p == pp.left)
pp.left = replacement;
else
pp.right = replacement;
p.left = p.right = p.parent = null;
}
TreeNode r = p.red ? root : balanceDeletion(root, replacement);
if (replacement == p) { // detach
TreeNode pp = p.parent;
p.parent = null;
if (pp != null) {
if (p == pp.left)
pp.left = null;
else if (p == pp.right)
pp.right = null;
}
}
if (movable)
moveRootToFront(tab, r);
}
/*判断table的指定位置用链表还是用红黑树*/
final void split(HashMap map, Node[] tab, int index, int bit) {
TreeNode b = this;/*tabel的第j个元素*/
// Relink into lo and hi lists, preserving order
TreeNode loHead = null, loTail = null;
TreeNode hiHead = null, hiTail = null;
int lc = 0, hc = 0;
for (TreeNode e = b, next; e != null; e = next) {
next = (TreeNode)e.next;
e.next = null;
/*https://www.zhihu.com/question/20733617*/
if ((e.hash & bit) == 0) {/*同一个table下标*//*链表名，和技术器不同*/
/*换成链表*/
if ((e.prev = loTail) == null)
loHead = e;
else
loTail.next = e;
loTail = e;
++lc;
}
else {
if ((e.prev = hiTail) == null)
hiHead = e;
else
hiTail.next = e;
hiTail = e;
++hc;
}
}
/* ------------------------------------------------------------ */
// Red-black tree methods, all adapted from CLR
static TreeNode rotateLeft(TreeNode root,
TreeNode p) {
TreeNode r, pp, rl;
if (p != null && (r = p.right) != null) {
if ((rl = p.right = r.left) != null)
rl.parent = p;
if ((pp = r.parent = p.parent) == null)
(root = r).red = false;
else if (pp.left == p)
pp.left = r;
else
pp.right = r;
r.left = p;
p.parent = r;
}
return root;
}
static TreeNode rotateRight(TreeNode root,
TreeNode p) {
TreeNode l, pp, lr;
if (p != null && (l = p.left) != null) {
if ((lr = p.left = l.right) != null)
lr.parent = p;
if ((pp = l.parent = p.parent) == null)
(root = l).red = false;
else if (pp.right == p)
pp.right = l;
else
pp.left = l;
l.right = p;
p.parent = l;
}
return root;
}
static TreeNode balanceInsertion(TreeNode root,
TreeNode x) {
x.red = true;
for (TreeNode xp, xpp, xppl, xppr;;) {
if ((xp = x.parent) == null) {
x.red = false;
return x;
}
else if (!xp.red || (xpp = xp.parent) == null)
return root;
if (xp == (xppl = xpp.left)) {
if ((xppr = xpp.right) != null && xppr.red) {
xppr.red = false;
xp.red = false;
xpp.red = true;
x = xpp;
}
else {
if (x == xp.right) {
root = rotateLeft(root, x = xp);
xpp = (xp = x.parent) == null ? null : xp.parent;
}
if (xp != null) {
xp.red = false;
if (xpp != null) {
xpp.red = true;
root = rotateRight(root, xpp);
}
}
}
}
else {
if (xppl != null && xppl.red) {
xppl.red = false;
xp.red = false;
xpp.red = true;
x = xpp;
}
else {
if (x == xp.left) {
root = rotateRight(root, x = xp);
xpp = (xp = x.parent) == null ? null : xp.parent;
}
if (xp != null) {
xp.red = false;
if (xpp != null) {
xpp.red = true;
root = rotateLeft(root, xpp);
}
}
}
}
}
}
static TreeNode balanceDeletion(TreeNode root,
TreeNode x) {
for (TreeNode xp, xpl, xpr;;) {
if (x == null || x == root)
return root;
else if ((xp = x.parent) == null) {
x.red = false;
return x;
}
else if (x.red) {
x.red = false;
return root;
}
else if ((xpl = xp.left) == x) {
if ((xpr = xp.right) != null && xpr.red) {
xpr.red = false;
xp.red = true;
root = rotateLeft(root, xp);
xpr = (xp = x.parent) == null ? null : xp.right;
}
if (xpr == null)
x = xp;
else {
TreeNode sl = xpr.left, sr = xpr.right;
if ((sr == null || !sr.red) &&
(sl == null || !sl.red)) {
xpr.red = true;
x = xp;
}
else {
if (sr == null || !sr.red) {
if (sl != null)
sl.red = false;
xpr.red = true;
root = rotateRight(root, xpr);
xpr = (xp = x.parent) == null ?
null : xp.right;
}
if (xpr != null) {
xpr.red = (xp == null) ? false : xp.red;
if ((sr = xpr.right) != null)
sr.red = false;
}
if (xp != null) {
xp.red = false;
root = rotateLeft(root, xp);
}
x = root;
}
}
}
else { // symmetric
if (xpl != null && xpl.red) {
xpl.red = false;
xp.red = true;
root = rotateRight(root, xp);
xpl = (xp = x.parent) == null ? null : xp.left;
}
if (xpl == null)
x = xp;
else {
TreeNode sl = xpl.left, sr = xpl.right;
if ((sl == null || !sl.red) &&
(sr == null || !sr.red)) {
xpl.red = true;
x = xp;
}
else {
if (sl == null || !sl.red) {
if (sr != null)
sr.red = false;
xpl.red = true;
root = rotateLeft(root, xpl);
xpl = (xp = x.parent) == null ?
null : xp.left;
}
if (xpl != null) {
xpl.red = (xp == null) ? false : xp.red;
if ((sl = xpl.left) != null)
sl.red = false;
}
if (xp != null) {
xp.red = false;
root = rotateRight(root, xp);
}
x = root;
}
}
}
}
}
/*检查是否符合红黑树*/
static boolean checkInvariants(TreeNode t) {
TreeNode tp = t.parent, tl = t.left, tr = t.right,
tb = t.prev, tn = (TreeNode)t.next;
if (tb != null && tb.next != t)
return false;
if (tn != null && tn.prev != t)
return false;
if (tp != null && t != tp.left && t != tp.right)
return false;
if (tl != null && (tl.parent != t || tl.hash > t.hash))
return false;
if (tr != null && (tr.parent != t || tr.hash < t.hash))
return false;
if (t.red && tl != null && tl.red && tr != null && tr.red)
return false;
if (tl != null && !checkInvariants(tl))
return false;
if (tr != null && !checkInvariants(tr))
return false;
return true;
}
}
}