本文适用于想要阅读HashMap源码的技术人员，如果只是想要简单了解一下HashMap内部结构的话，该文不适用。
本文的是在JDK7的HashMap的基础上写的注释，所以不懂的请先看JDK7的HashMap。
JDK8的HashMap主要难点在于红黑树，相比JDK7主要多了一个链表转树（树转链表）和红黑树平衡的逻辑。
（建议阅读源码时手头有一份《算法导论》，我的下载资源里有完整高清的pdf）
写的比较急，主要对put、remove、resize做了分析，大家要是看的有疑问的话请评论留言，
虽然很少上，但是看到了还是会给大家回复的。
共同进步。（2018-03-02）
package com.ticket.web.controller;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.Function;
/**
* Hash table based implementation of the Map interface. This
* implementation provides all of the optional map operations, and permits
* null values and the null key. (The HashMap
* class is roughly equivalent to Hashtable, except that it is
* unsynchronized and permits nulls.) This class makes no guarantees as to
* the order of the map; in particular, it does not guarantee that the order
* will remain constant over time.
*
* This implementation provides constant-time performance for the basic
* operations (get and put), assuming the hash function
* disperses the elements properly among the buckets. Iteration over
* collection views requires time proportional to the "capacity" of the
* HashMap instance (the number of buckets) plus its size (the number
* of key-value mappings). Thus, it's very important not to set the initial
* capacity too high (or the load factor too low) if iteration performance is
* important.
*
* An instance of HashMap has two parameters that affect its
* performance: initial capacity and load factor. The
* capacity is the number of buckets in the hash table, and the initial
* capacity is simply the capacity at the time the hash table is created. The
* load factor is a measure of how full the hash table is allowed to
* get before its capacity is automatically increased. When the number of
* entries in the hash table exceeds the product of the load factor and the
* current capacity, the hash table is rehashed (that is, internal data
* structures are rebuilt) so that the hash table has approximately twice the
* number of buckets.
*
* As a general rule, the default load factor (.75) offers a good
* tradeoff between time and space costs. Higher values decrease the
* space overhead but increase the lookup cost (reflected in most of
* the operations of the HashMap class, including
* get and put). The expected number of entries in
* the map and its load factor should be taken into account when
* setting its initial capacity, so as to minimize the number of
* rehash operations. If the initial capacity is greater than the
* maximum number of entries divided by the load factor, no rehash
* operations will ever occur.
*
* If many mappings are to be stored in a HashMap
* instance, creating it with a sufficiently large capacity will allow
* the mappings to be stored more efficiently than letting it perform
* automatic rehashing as needed to grow the table. Note that using
* many keys with the same {@code hashCode()} is a sure way to slow
* down performance of any hash table. To ameliorate impact, when keys
* are {@link Comparable}, this class may use comparison order among
* keys to help break ties.
*
*
Note that this implementation is not synchronized.
* If multiple threads access a hash map concurrently, and at least one of
* the threads modifies the map structurally, it must be
* synchronized externally. (A structural modification is any operation
* that adds or deletes one or more mappings; merely changing the value
* associated with a key that an instance already contains is not a
* structural modification.) This is typically accomplished by
* synchronizing on some object that naturally encapsulates the map.
*
* If no such object exists, the map should be "wrapped" using the
* {@link Collections#synchronizedMap Collections.synchronizedMap}
* method. This is best done at creation time, to prevent accidental
* unsynchronized access to the map:
* Map m = Collections.synchronizedMap(new HashMap(...));
*
* The iterators returned by all of this class's "collection view methods"
* are fail-fast: if the map is structurally modified at any time after
* the iterator is created, in any way except through the iterator's own
* remove method, the iterator will throw a
* {@link ConcurrentModificationException}. Thus, in the face of concurrent
* modification, the iterator fails quickly and cleanly, rather than risking
* arbitrary, non-deterministic behavior at an undetermined time in the
* future.
*
* Note that the fail-fast behavior of an iterator cannot be guaranteed
* as it is, generally speaking, impossible to make any hard guarantees in the
* presence of unsynchronized concurrent modification. Fail-fast iterators
* throw ConcurrentModificationException on a best-effort basis.
* Therefore, it would be wrong to write a program that depended on this
* exception for its correctness: the fail-fast behavior of iterators
* should be used only to detect bugs.
*
* This class is a member of the
* {@docRoot}/../technotes/guides/collections/index.html">
* Java Collections Framework.
*
* @param <
K>
the type of keys maintained by this map
* @param <
V>
the type of mapped values
*
* @see Object#hashCode()
* @see Collection
* @see Map
* @see TreeMap
* @see Hashtable
* @since 1.2
*/
public class HashMap
,V> extends AbstractMap,V>
implements Map,V>, Cloneable, Serializable {
private static final long serialVersionUID = 362498820763181265L;
/*
* Implementation notes.
*
* This map usually acts as a binned (bucketed) hash table, but
* when bins get too large, they are transformed into bins of
* TreeNodes, each structured similarly to those in
* java.util.TreeMap. Most methods try to use normal bins, but
* relay to TreeNode methods when applicable (simply by checking
* instanceof a node). Bins of TreeNodes may be traversed and
* used like any others, but additionally support faster lookup
* when overpopulated. However, since the vast majority of bins in
* normal use are not overpopulated, checking for existence of
* tree bins may be delayed in the course of table methods.
*
* Tree bins (i.e., bins whose elements are all TreeNodes) are
* ordered primarily by hashCode, but in the case of ties, if two
* elements are of the same "class C implements Comparable",
* type then their compareTo method is used for ordering. (We
* conservatively check generic types via reflection to validate
* this -- see method comparableClassFor). The added complexity
* of tree bins is worthwhile in providing worst-case O(log n)
* operations when keys either have distinct hashes or are
* orderable, Thus, performance degrades gracefully under
* accidental or malicious usages in which hashCode() methods
* return values that are poorly distributed, as well as those in
* which many keys share a hashCode, so long as they are also
* Comparable. (If neither of these apply, we may waste about a
* factor of two in time and space compared to taking no
* precautions. But the only known cases stem from poor user
* programming practices that are already so slow that this makes
* little difference.)
*
* Because TreeNodes are about twice the size of regular nodes, we
* use them only when bins contain enough nodes to warrant use
* (see TREEIFY_THRESHOLD). And when they become too small (due to
* removal or resizing) they are converted back to plain bins. In
* usages with well-distributed user hashCodes, tree bins are
* rarely used. Ideally, under random hashCodes, the frequency of
* nodes in bins follows a Poisson distribution
* (http://en.wikipedia.org/wiki/Poisson_distribution) with a
* parameter of about 0.5 on average for the default resizing
* threshold of 0.75, although with a large variance because of
* resizing granularity. Ignoring variance, the expected
* occurrences of list size k are (exp(-0.5) * pow(0.5, k) /
* factorial(k)). The first values are:
*
* 0: 0.60653066
* 1: 0.30326533
* 2: 0.07581633
* 3: 0.01263606
* 4: 0.00157952
* 5: 0.00015795
* 6: 0.00001316
* 7: 0.00000094
* 8: 0.00000006
* more: less than 1 in ten million
*
* The root of a tree bin is normally its first node. However,
* sometimes (currently only upon Iterator.remove), the root might
* be elsewhere, but can be recovered following parent links
* (method TreeNode.root()).
*
* All applicable internal methods accept a hash code as an
* argument (as normally supplied from a public method), allowing
* them to call each other without recomputing user hashCodes.
* Most internal methods also accept a "tab" argument, that is
* normally the current table, but may be a new or old one when
* resizing or converting.
*
* When bin lists are treeified, split, or untreeified, we keep
* them in the same relative access/traversal order (i.e., field
* Node.next) to better preserve locality, and to slightly
* simplify handling of splits and traversals that invoke
* iterator.remove. When using comparators on insertion, to keep a
* total ordering (or as close as is required here) across
* rebalancings, we compare classes and identityHashCodes as
* tie-breakers.
*
* The use and transitions among plain vs tree modes is
* complicated by the existence of subclass LinkedHashMap. See
* below for hook methods defined to be invoked upon insertion,
* removal and access that allow LinkedHashMap internals to
* otherwise remain independent of these mechanics. (This also
* requires that a map instance be passed to some utility methods
* that may create new nodes.)
*
* The concurrent-programming-like SSA-based coding style helps
* avoid aliasing errors amid all of the twisty pointer operations.
*/
/**
* The default initial capacity - MUST be a power of two.
*/
static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16
/**
* The maximum capacity, used if a higher value is implicitly specified
* by either of the constructors with arguments.
* MUST be a power of two <= 1<<30.
*/
static final int MAXIMUM_CAPACITY = 1 << 30;
/**
* The load factor used when none specified in constructor.
*/
static final float DEFAULT_LOAD_FACTOR = 0.75f;
/**
* The bin count threshold for using a tree rather than list for a
* bin. Bins are converted to trees when adding an element to a
* bin with at least this many nodes. The value must be greater
* than 2 and should be at least 8 to mesh with assumptions in
* tree removal about conversion back to plain bins upon
* shrinkage.
*/
static final int TREEIFY_THRESHOLD = 8;
/**
* The bin count threshold for untreeifying a (split) bin during a
* resize operation. Should be less than TREEIFY_THRESHOLD, and at
* most 6 to mesh with shrinkage detection under removal.
*/
static final int UNTREEIFY_THRESHOLD = 6;
/**
* The smallest table capacity for which bins may be treeified.
* (Otherwise the table is resized if too many nodes in a bin.)
* Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts
* between resizing and treeification thresholds.
*/
/**
* 如果table的容量少于64，那么即使冲突结点数达到TREEIFY_THRESHOLD后不会把该单链表调整成红黑数，而是将table扩容
*/
static final int MIN_TREEIFY_CAPACITY = 64;
/**
* Basic hash bin node, used for most entries. (See below for
* TreeNode subclass, and in LinkedHashMap for its Entry subclass.)
* 链表的节点
*/
static class Node,V> implements Map.Entry,V> {
final int hash;
final K key;
V value;
Node,V> next;
Node(int hash, K key, V value, Node,V> 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; }
public final int hashCode() {
return Objects.hashCode(key) ^ Objects.hashCode(value);
}
public final V setValue(V newValue) {
V oldValue = value;
value = newValue;
return oldValue;
}
public final boolean equals(Object o) {
if (o == this)
return true;
if (o instanceof Map.Entry) {
Map.Entry,?> e = (Map.Entry,?>)o;
if (Objects.equals(key, e.getKey()) &&
Objects.equals(value, e.getValue()))
return true;
}
return false;
}
}
/* ---------------- Static utilities -------------- */
/**
* Computes key.hashCode() and spreads (XORs) higher bits of hash
* to lower. Because the table uses power-of-two masking, sets of
* hashes that vary only in bits above the current mask will
* always collide. (Among known examples are sets of Float keys
* holding consecutive whole numbers in small tables.) So we
* apply a transform that spreads the impact of higher bits
* downward. There is a tradeoff between speed, utility, and
* quality of bit-spreading. Because many common sets of hashes
* are already reasonably distributed (so don't benefit from
* spreading), and because we use trees to handle large sets of
* collisions in bins, we just XOR some shifted bits in the
* cheapest possible way to reduce systematic lossage, as well as
* to incorporate impact of the highest bits that would otherwise
* never be used in index calculations because of table bounds.
*/
/**
* 计算hashCode的值，并且通过"异或"计算将高位的16位信息影响到到低位的16位里去。
*/
static final int hash(Object key) {
int h;
return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
}
/**
* Returns x's Class if it is of the form "class C implements
* Comparable", else null.
* 检查是否是可以比较的类型，比如String或实现了Comparable
*/
static Class comparableClassFor(Object x) {
if (x instanceof Comparable) {
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) {
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;
}
}
}
return null;
}
/**
* Returns k.compareTo(x) if x matches kc (k's screened comparable
* class), else 0.
*/
@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
static int compareComparables(Class kc, Object k, Object x) {
return (x == null || x.getClass() != kc ? 0 :
((Comparable)k).compareTo(x));
}
/**
* Returns a power of two size for the given target capacity.
* 这里通过位移的方式来计算大于cap的最小2倍数，位移数值为1，2，4，8，16的原因在于
* 1+2=3，1+2+4=7，这样就保证了之前位移过的位通过异或得到的全是1，所以可以直接跳过，
* 而不是采用位移1，2，3，4，5，6…16这样的方式
* 特意提醒一下：这里权限是default，所以是同包下才能调用，免的有时候突然忘了发现调用不了
*/
static final int tableSizeFor(int cap) {
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 -------------- */
/**
* The table, initialized on first use, and resized as
* necessary. When allocated, length is always a power of two.
* (We also tolerate length zero in some operations to allow
* bootstrapping mechanics that are currently not needed.)
*/
transient Node,V>[] table;
/**
* Holds cached entrySet(). Note that AbstractMap fields are used
* for keySet() and values().
*/
transient Set,V>> entrySet;
/**
* The number of key-value mappings contained in this map.
*/
transient int size;
/**
* The number of times this HashMap has been structurally modified
* Structural modifications are those that change the number of mappings in
* the HashMap or otherwise modify its internal structure (e.g.,
* rehash). This field is used to make iterators on Collection-views of
* the HashMap fail-fast. (See ConcurrentModificationException).
*/
transient int modCount;
/**
* The next size value at which to resize (capacity * load factor).
*
* @serial
*/
// (The javadoc description is true upon serialization.
// Additionally, if the table array has not been allocated, this
// field holds the initial array capacity, or zero signifying
// DEFAULT_INITIAL_CAPACITY.)
int threshold;
/**
* The load factor for the hash table.
*
* @serial
*/
final float loadFactor;
/* ---------------- Public operations -------------- */
/**
* Constructs an empty HashMap with the specified initial
* capacity and load factor.
*
* @param initialCapacity the initial capacity
* @param loadFactor the load factor
* @throws IllegalArgumentException if the initial capacity is negative
* or the load factor is nonpositive
*/
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))
throw new IllegalArgumentException("Illegal load factor: " +
loadFactor);
this.loadFactor = loadFactor;
this.threshold = tableSizeFor(initialCapacity);
}
/**
* Constructs an empty HashMap with the specified initial
* capacity and the default load factor (0.75).
*
* @param initialCapacity the initial capacity.
* @throws IllegalArgumentException if the initial capacity is negative.
*/
public HashMap(int initialCapacity) {
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
/**
* Constructs an empty HashMap with the default initial capacity
* (16) and the default load factor (0.75).
*/
public HashMap() {
this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
}
/**
* Constructs a new HashMap with the same mappings as the
* specified Map. The HashMap is created with
* default load factor (0.75) and an initial capacity sufficient to
* hold the mappings in the specified Map.
*
* @param m the map whose mappings are to be placed in this map
* @throws NullPointerException if the specified map is null
*/
public HashMap(Mapextends K, ? extends V> m) {
this.loadFactor = DEFAULT_LOAD_FACTOR;
putMapEntries(m, false);
}
/**
* Implements Map.putAll and Map constructor
*
* @param m the map
* @param evict false when initially constructing this map, else
* true (relayed to method afterNodeInsertion).
*/
final void putMapEntries(Mapextends K, ? extends V> m, boolean evict) {
int s = m.size();
if (s > 0) {
if (table == null) { // pre-size
float ft = ((float)s / loadFactor) + 1.0F;
int t = ((ft < (float)MAXIMUM_CAPACITY) ?
(int)ft : MAXIMUM_CAPACITY);
if (t > threshold)
threshold = tableSizeFor(t);
}
else if (s > threshold)
resize();
for (Map.Entryextends K, ? extends V> e : m.entrySet()) {
K key = e.getKey();
V value = e.getValue();
putVal(hash(key), key, value, false, evict);
}
}
}
/**
* Returns the number of key-value mappings in this map.
*
* @return the number of key-value mappings in this map
*/
public int size() {
return size;
}
/**
* Returns true if this map contains no key-value mappings.
*
* @return true if this map contains no key-value mappings
*/
public boolean isEmpty() {
return size == 0;
}
/**
* Returns the value to which the specified key is mapped,
* or {@code null} if this map contains no mapping for the key.
*
* More formally, if this map contains a mapping from a key
* {@code k} to a value {@code v} such that {@code (key==null ? k==null :
* key.equals(k))}, then this method returns {@code v}; otherwise
* it returns {@code null}. (There can be at most one such mapping.)
*
* A return value of {@code null} does not necessarily
* indicate that the map contains no mapping for the key; it's also
* possible that the map explicitly maps the key to {@code null}.
* The {@link #containsKey containsKey} operation may be used to
* distinguish these two cases.
*
* @see #put(Object, Object)
*/
public V get(Object key) {
Node,V> e;
return (e = getNode(hash(key), key)) == null ? null : e.value;
}
/**
* Implements Map.get and related methods
*
* @param hash hash for key
* @param key the key
* @return the node, or null if none
*
* tab[(n - 1) & hash]相当于jdk1.7中的indexFor()，
* 如果length为2的N次方，(n-1)&hash则相当于取模运算
*/
final Node,V> getNode(int hash, Object key) {
Node,V>[] tab; Node,V> 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))))
return first;
//如果链表上不止一个元素则先判断是否已经树化，
//否则遍历链表查找
if ((e = first.next) != null) {
if (first instanceof TreeNode)
return ((TreeNode,V>)first).getTreeNode(hash, key);
do {
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k))))
return e;
} while ((e = e.next) != null);
}
}
return null;
}
/**
* Returns true if this map contains a mapping for the
* specified key.
*
* @param key The key whose presence in this map is to be tested
* @return true if this map contains a mapping for the specified
* key.
*/
public boolean containsKey(Object key) {
return getNode(hash(key), key) != null;
}
/**
* Associates the specified value with the specified key in this map.
* If the map previously contained a mapping for the key, the old
* value is replaced.
*
* @param key key with which the specified value is to be associated
* @param value value to be associated with the specified key
* @return the previous value associated with key, or
* null if there was no mapping for key.
* (A null return can also indicate that the map
* previously associated null with key.)
*/
public V put(K key, V value) {
return putVal(hash(key), key, value, false, true);
}
/**
* Implements Map.put and related methods
*
* @param hash hash for key
* @param key the key
* @param value the value to put
* @param onlyIfAbsent if true, don't change existing value
* @param evict if false, the table is in creation mode.
* @return previous value, or null if none
*/
final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
boolean evict) {
Node,V>[] tab; Node,V> p; int n, i;
if ((tab = table) == null || (n = tab.length) == 0)
n = (tab = resize()).length;
//如果桶上这个位置还没有node，那么就直接指定
if ((p = tab[i = (n - 1) & hash]) == null)
tab[i] = newNode(hash, key, value, null);
else {
Node,V> e; K k;
//先检查这个桶的第一个位置（因为大部分桶都是没有冲突的）
if (p.hash == hash &&
((k = p.key) == key || (key != null && key.equals(k))))
e = p;
//如果桶的第一个位置不相等，再检查这个链表是不是树状结构
else if (p instanceof TreeNode)
e = ((TreeNode,V>)p).putTreeVal(this, tab, hash, key, value);
else {
//如果这个链表不是树状结构，那么循环链表，将元素放到该链表表尾
//（注意，JDK1.7的时候，元素被放在链表的表头，因为新元素被再次使用的概率更大），
// 或者链表中已经有该值，那么直接跳出
for (int binCount = 0; ; ++binCount) {
if ((e = p.next) == null) {
p.next = newNode(hash, key, value, null);
if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st
//转化成红黑树
treeifyBin(tab, hash);
break;
}
//如果链表中存在相同的值，则直接返回
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k))))
break;
p = e;
}
}
//如果有相同的key存在，那么就替换这个key的value
if (e != null) { // existing mapping for key
V oldValue = e.value;
if (!onlyIfAbsent || oldValue == null)
e.value = value;
//这里还是一个给子类重写的空函数（jdk1.7的时候这里是recordAccess()），
//比如在LinkedHashMap中，控制插入顺序和访问顺序
//因为HashMap在JDK1.8新增了Node，所以LinkedHashMap在这里也做了Node处理，
//即这里控制Node的插入顺序（afterNodeInsertion）和访问顺序（afterNodeAccess）
afterNodeAccess(e);
return oldValue;
}
}
++modCount;
if (++size > threshold)
resize();
afterNodeInsertion(evict);
return null;
}
/**
* Initializes or doubles table size. If null, allocates in
* accord with initial capacity target held in field threshold.
* Otherwise, because we are using power-of-two expansion, the
* elements from each bin must either stay at same index, or move
* with a power of two offset in the new table.
* 扩容时，每个值在table中都必须保持在原来的位置或者移动一个2倍数的偏移量
* @return the table
*/
final Node,V>[] resize() {
Node,V>[] oldTab = table;
int oldCap = (oldTab == null) ? 0 : oldTab.length;
int oldThr = threshold;
int newCap, newThr = 0;
if (oldCap > 0) {
if (oldCap >= MAXIMUM_CAPACITY) {
threshold = Integer.MAX_VALUE;
return oldTab;
//如果扩容一倍以后比最大容量还小，并且旧容量大于16，那么阈值也扩容一倍
//阈值 = 容量 * loadFactor
} else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
oldCap >= DEFAULT_INITIAL_CAPACITY)
newThr = oldThr << 1; // double threshold
}
else if (oldThr > 0) // initial capacity was placed in threshold
newCap = oldThr;
else { // zero initial threshold signifies using defaults
newCap = DEFAULT_INITIAL_CAPACITY;
newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY);
}
if (newThr == 0) {
float ft = (float)newCap * loadFactor;
newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
(int)ft : Integer.MAX_VALUE);
}
threshold = newThr;
@SuppressWarnings({"rawtypes","unchecked"})
Node,V>[] newTab = (Node,V>[])new Node[newCap];
table = newTab;
//上面确认扩容的大小与阈值，下面确定元素在新表中的位置
if (oldTab != null) {
for (int j = 0; j < oldCap; ++j) {
Node,V> e;
if ((e = oldTab[j]) != null) {
oldTab[j] = null;
if (e.next == null)
newTab[e.hash & (newCap - 1)] = e;
else if (e instanceof TreeNode)
((TreeNode,V>)e).split(this, newTab, j, oldCap);
else { // preserve order
//这里将扩容的table分为两份，旧的表和新的表,
Node,V> loHead = null, loTail = null;
Node,V> hiHead = null, hiTail = null;
Node,V> next;
do {
next = e.next;
//这里没用hash&(cap-1)，oldCap是2的倍数，所以二进制都是100000……
//这里hash&oldCap就只有两种值：1、0 2、oldCap
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;
}
/**
* Replaces all linked nodes in bin at index for given hash unless
* table is too small, in which case resizes instead.
*/
final void treeifyBin(Node,V>[] tab, int hash) {
int n, index; Node,V> e;
//数组长度如果小于转成红黑树的最小容量(即64)，则将数组大小扩容
if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)
resize();
//如果这个链表不为空
else if ((e = tab[index = (n - 1) & hash]) != null) {
//创建TreeNode组成的链表,hd即head
TreeNode,V> hd = null, tl = null;
// 遍历链表，将链表元素转化成TreeNode链
do {
// 调用replacementTreeNode构造TreeNode
TreeNode,V> p = replacementTreeNode(e, null);
// TreeNode链为空，将元素设置为hd的首个节点
if (tl == null)
hd = p;
else {
// TreeNode链不为空，向TreeNode链后面添加元素
p.prev = tl;
tl.next = p;
}
tl = p;
} while ((e = e.next) != null);
//对TreeNode链表树化
if ((tab[index] = hd) != null)
hd.treeify(tab);
}
}
/**
* Copies all of the mappings from the specified map to this map.
* These mappings will replace any mappings that this map had for
* any of the keys currently in the specified map.
*
* @param m mappings to be stored in this map
* @throws NullPointerException if the specified map is null
*/
public void putAll(Mapextends K, ? extends V> m) {
putMapEntries(m, true);
}
/**
* Removes the mapping for the specified key from this map if present.
*
* @param key key whose mapping is to be removed from the map
* @return the previous value associated with key, or
* null if there was no mapping for key.
* (A null return can also indicate that the map
* previously associated null with key.)
*/
public V remove(Object key) {
Node,V> e;
return (e = removeNode(hash(key), key, null, false, true)) == null ?
null : e.value;
}
/**
* Implements Map.remove and related methods
*
* @param hash hash for key
* @param key the key
* @param value the value to match if matchValue, else ignored
* @param matchValue if true only remove if value is equal
* @param movable if false do not move other nodes while removing
* @return the node, or null if none
*/
final Node,V> removeNode(int hash, Object key, Object value,
boolean matchValue, boolean movable) {
Node,V>[] tab; Node,V> p; int n, index;
//map不为空，且tab[index]不为空
if ((tab = table) != null && (n = tab.length) > 0 &&
(p = tab[index = (n - 1) & hash]) != null) {
Node,V> node = null, e; K k; V v;
//如果链表中第一个直接可以找到
if (p.hash == hash &&
((k = p.key) == key || (key != null && key.equals(k))))
node = p;
//如果有多个节点
else if ((e = p.next) != null) {
//如果是红黑树
if (p instanceof TreeNode)
node = ((TreeNode,V>)p).getTreeNode(hash, key);
else {
//如果是链表，就循环遍历查询
do {
if (e.hash == hash &&
((k = e.key) == key ||
(key != null && key.equals(k)))) {
node = e;
break;
}
p = e;
} while ((e = e.next) != null);
}
}
//如果存在这个节点
if (node != null && (!matchValue || (v = node.value) == value ||
(value != null && value.equals(v)))) {
//如果节点是树节点
if (node instanceof TreeNode)
((TreeNode,V>)node).removeTreeNode(this, tab, movable);
//如果节点是链表头
else if (node == p)
tab[index] = node.next;
//如果节点不是链表头
else
p.next = node.next;
++modCount;
--size;
//linkedHashMap的钩子
afterNodeRemoval(node);
return node;
}
}
return null;
}
/**
* Removes all of the mappings from this map.
* The map will be empty after this call returns.
*/
public void clear() {
Node,V>[] tab;
modCount++;
if ((tab = table) != null && size > 0) {
size = 0;
for (int i = 0; i < tab.length; ++i)
tab[i] = null;
}
}
/**
* Returns true if this map maps one or more keys to the
* specified value.
*
* @param value value whose presence in this map is to be tested
* @return true if this map maps one or more keys to the
* specified value
*/
public boolean containsValue(Object value) {
Node,V>[] tab; V v;
if ((tab = table) != null && size > 0) {
for (int i = 0; i < tab.length; ++i) {
for (Node,V> e = tab[i]; e != null; e = e.next) {
if ((v = e.value) == value ||
(value != null && value.equals(v)))
return true;
}
}
}
return false;
}
/**
* Returns a {@link Set} view of the keys contained in this map.
* The set is backed by the map, so changes to the map are
* reflected in the set, and vice-versa. If the map is modified
* while an iteration over the set is in progress (except through
* the iterator's own remove operation), the results of
* the iteration are undefined. The set supports element removal,
* which removes the corresponding mapping from the map, via the
* Iterator.remove, Set.remove,
* removeAll, retainAll, and clear
* operations. It does not support the add or addAll
* operations.
*
* @return a set view of the keys contained in this map
*/
public Set keySet() {
Set ks = keySet;
if (ks == null) {
ks = new KeySet();
keySet = ks;
}
return ks;
}
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(Consumersuper K> action) {
Node,V>[] 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,V> e = tab[i]; e != null; e = e.next)
action.accept(e.key);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
}
/**
* Returns a {@link Collection} view of the values contained in this map.
* The collection is backed by the map, so changes to the map are
* reflected in the collection, and vice-versa. If the map is
* modified while an iteration over the collection is in progress
* (except through the iterator's own remove operation),
* the results of the iteration are undefined. The collection
* supports element removal, which removes the corresponding
* mapping from the map, via the Iterator.remove,
* Collection.remove, removeAll,
* retainAll and clear operations. It does not
* support the add or addAll operations.
*
* @return a view of the values contained in this map
*/
public Collection values() {
Collection vs = values;
if (vs == null) {
vs = new Values();
values = vs;
}
return vs;
}
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(Consumersuper V> action) {
Node,V>[] 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,V> e = tab[i]; e != null; e = e.next)
action.accept(e.value);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
}
/**
* Returns a {@link Set} view of the mappings contained in this map.
* The set is backed by the map, so changes to the map are
* reflected in the set, and vice-versa. If the map is modified
* while an iteration over the set is in progress (except through
* the iterator's own remove operation, or through the
* setValue operation on a map entry returned by the
* iterator) the results of the iteration are undefined. The set
* supports element removal, which removes the corresponding
* mapping from the map, via the Iterator.remove,
* Set.remove, removeAll, retainAll and
* clear operations. It does not support the
* add or addAll operations.
*
* @return a set view of the mappings contained in this map
*/
public Set,V>> entrySet() {
Set,V>> es;
return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
}
final class EntrySet extends AbstractSet,V>> {
public final int size() { return size; }
public final void clear() { HashMap.this.clear(); }
public final Iterator,V>> 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,V> 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,V>> spliterator() {
return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
}
public final void forEach(Consumersuper Map.Entry,V>> action) {
Node,V>[] 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,V> e = tab[i]; e != null; e = e.next)
action.accept(e);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
}
// Overrides of JDK8 Map extension methods
@Override
public V getOrDefault(Object key, V defaultValue) {
Node,V> e;
return (e = getNode(hash(key), key)) == null ? defaultValue : e.value;
}
@Override
public V putIfAbsent(K key, V value) {
return putVal(hash(key), key, value, true, true);
}
@Override
public boolean remove(Object key, Object value) {
return removeNode(hash(key), key, value, true, true) != null;
}
@Override
public boolean replace(K key, V oldValue, V newValue) {
Node,V> 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;
}
@Override
public V replace(K key, V value) {
Node,V> e;
if ((e = getNode(hash(key), key)) != null) {
V oldValue = e.value;
e.value = value;
afterNodeAccess(e);
return oldValue;
}
return null;
}
@Override
public V computeIfAbsent(K key,
Functionsuper K, ? extends V> mappingFunction) {
if (mappingFunction == null)
throw new NullPointerException();
int hash = hash(key);
Node,V>[] tab; Node,V> first; int n, i;
int binCount = 0;
TreeNode,V> t = null;
Node,V> 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,V>)first).getTreeNode(hash, key);
else {
Node,V> 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,
BiFunctionsuper K, ? super V, ? extends V> remappingFunction) {
if (remappingFunction == null)
throw new NullPointerException();
Node,V> 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,
BiFunctionsuper K, ? super V, ? extends V> remappingFunction) {
if (remappingFunction == null)
throw new NullPointerException();
int hash = hash(key);
Node,V>[] tab; Node,V> first; int n, i;
int binCount = 0;
TreeNode,V> t = null;
Node,V> 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,V>)first).getTreeNode(hash, key);
else {
Node,V> 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,
BiFunctionsuper V, ? super V, ? extends V> remappingFunction) {
if (value == null)
throw new NullPointerException();
if (remappingFunction == null)
throw new NullPointerException();
int hash = hash(key);
Node,V>[] tab; Node,V> first; int n, i;
int binCount = 0;
TreeNode,V> t = null;
Node,V> 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,V>)first).getTreeNode(hash, key);
else {
Node,V> 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(BiConsumersuper K, ? super V> action) {
Node,V>[] 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,V> e = tab[i]; e != null; e = e.next)
action.accept(e.key, e.value);
}
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
@Override
public void replaceAll(BiFunctionsuper K, ? super V, ? extends V> function) {
Node,V>[] 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,V> 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
/**
* Returns a shallow copy of this HashMap instance: the keys and
* values themselves are not cloned.
*
* @return a shallow copy of this map
*/
@SuppressWarnings("unchecked")
@Override
public Object clone() {
HashMap,V> result;
try {
result = (HashMap,V>)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
final float loadFactor() { return loadFactor; }
final int capacity() {
return (table != null) ? table.length :
(threshold > 0) ? threshold :
DEFAULT_INITIAL_CAPACITY;
}
/**
* Save the state of the HashMap instance to a stream (i.e.,
* serialize it).
*
* @serialData The capacity of the HashMap (the length of the
* bucket array) is emitted (int), followed by the
* size (an int, the number of key-value
* mappings), followed by the key (Object) and value (Object)
* for each key-value mapping. The key-value mappings are
* emitted in no particular order.
*/
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);
}
/**
* Reconstitute the {@code HashMap} instance from a stream (i.e.,
* deserialize it).
*/
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,V>[] tab = (Node,V>[])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
abstract class HashIterator {
Node,V> next; // next entry to return
Node,V> current; // current entry
int expectedModCount; // for fast-fail
int index; // current slot
HashIterator() {
expectedModCount = modCount;
Node,V>[] 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,V> nextNode() {
Node,V>[] t;
Node,V> 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,V> 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;
}
}
final class KeyIterator extends HashIterator
implements Iterator {
public final K next() { return nextNode().key; }
}
final class ValueIterator extends HashIterator
implements Iterator {
public final V next() { return nextNode().value; }
}
final class EntryIterator extends HashIterator
implements Iterator,V>> {
public final Map.Entry,V> next() { return nextNode(); }
}
/* ------------------------------------------------------------ */
// spliterators
static class HashMapSpliterator,V> {
final HashMap,V> map;
Node,V> 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,V> 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,V> m = map;
est = m.size;
expectedModCount = m.modCount;
Node,V>[] 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,V>
extends HashMapSpliterator,V>
implements Spliterator {
KeySpliterator(HashMap,V> m, int origin, int fence, int est,
int expectedModCount) {
super(m, origin, fence, est, expectedModCount);
}
public KeySpliterator,V> 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(Consumersuper K> action) {
int i, hi, mc;
if (action == null)
throw new NullPointerException();
HashMap,V> m = map;
Node,V>[] 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,V> 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(Consumersuper K> action) {
int hi;
if (action == null)
throw new NullPointerException();
Node,V>[] 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,V>
extends HashMapSpliterator,V>
implements Spliterator {
ValueSpliterator(HashMap,V> m, int origin, int fence, int est,
int expectedModCount) {
super(m, origin, fence, est, expectedModCount);
}
public ValueSpliterator,V> 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(Consumersuper V> action) {
int i, hi, mc;
if (action == null)
throw new NullPointerException();
HashMap,V> m = map;
Node,V>[] 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,V> 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(Consumersuper V> action) {
int hi;
if (action == null)
throw new NullPointerException();
Node,V>[] 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,V>
extends HashMapSpliterator,V>
implements Spliterator,V>> {
EntrySpliterator(HashMap,V> m, int origin, int fence, int est,
int expectedModCount) {
super(m, origin, fence, est, expectedModCount);
}
public EntrySpliterator,V> 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(Consumersuper Map.Entry,V>> action) {
int i, hi, mc;
if (action == null)
throw new NullPointerException();
HashMap,V> m = map;
Node,V>[] 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,V> 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(Consumersuper Map.Entry,V>> action) {
int hi;
if (action == null)
throw new NullPointerException();
Node,V>[] 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,V> 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
Node,V> newNode(int hash, K key, V value, Node,V> next) {
return new Node<>(hash, key, value, next);
}
// For conversion from TreeNodes to plain nodes
Node,V> replacementNode(Node,V> p, Node,V> next) {
return new Node<>(p.hash, p.key, p.value, next);
}
// Create a tree bin node
TreeNode,V> newTreeNode(int hash, K key, V value, Node,V> next) {
return new TreeNode<>(hash, key, value, next);
}
// For treeifyBin
TreeNode,V> replacementTreeNode(Node,V> p, Node,V> next) {
return new TreeNode<>(p.hash, p.key, p.value, next);
}
/**
* Reset to initial default state. Called by clone and readObject.
*/
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,V> p) { }
void afterNodeInsertion(boolean evict) { }
void afterNodeRemoval(Node,V> p) { }
// Called only from writeObject, to ensure compatible ordering.
void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
Node,V>[] tab;
if (size > 0 && (tab = table) != null) {
for (int i = 0; i < tab.length; ++i) {
for (Node,V> e = tab[i]; e != null; e = e.next) {
s.writeObject(e.key);
s.writeObject(e.value);
}
}
}
}
/* ------------------------------------------------------------ */
// Tree bins
/**
* Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
* extends Node) so can be used as extension of either regular or
* linked node.
*/
static final class TreeNode,V> extends LinkedHashMap.Entry,V> {
TreeNode,V> parent; // red-black tree links
TreeNode,V> left;
TreeNode,V> right;
TreeNode,V> prev; // needed to unlink next upon deletion
boolean red;
TreeNode(int hash, K key, V val, Node,V> next) {
super(hash, key, val, next);
}
/**
* Returns root of tree containing this node.
*/
final TreeNode,V> root() {
for (TreeNode,V> r = this, p;;) {
if ((p = r.parent) == null)
return r;
r = p;
}
}
/**
* Ensures that the given root is the first node of its bin.
*/
static ,V> void moveRootToFront(Node,V>[] tab, TreeNode,V> root) {
int n;
if (root != null && tab != null && (n = tab.length) > 0) {
int index = (n - 1) & root.hash;
TreeNode,V> first = (TreeNode,V>)tab[index];
if (root != first) {
Node,V> rn;
tab[index] = root;
TreeNode,V> rp = root.prev;
if ((rn = root.next) != null)
((TreeNode,V>)rn).prev = rp;
if (rp != null)
rp.next = rn;
if (first != null)
first.prev = root;
root.next = first;
root.prev = null;
}
assert checkInvariants(root);
}
}
/**
* Finds the node starting at root p with the given hash and key.
* The kc argument caches comparableClassFor(key) upon first use
* comparing keys.
*/
/**
* 查询树节点，根据要查询的节点的hash值类判断大小，如果hash值大小一样就比较key值
* 如果该节点只有一个孩子或没有孩子了，就取最后这一个或返回null
*
* kc != null这里的条件，在该类中没有用到
*/
final TreeNode,V> find(int h, Object k, Class kc) {
TreeNode,V> p = this;
do {
int ph, dir; K pk;
TreeNode,V> 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;
}
/**
* Calls find for root node.
*/
final TreeNode,V> getTreeNode(int h, Object k) {
return ((parent != null) ? root() : this).find(h, k, null);
}
/**
* Tie-breaking utility for ordering insertions when equal
* hashCodes and non-comparable. We don't require a total
* order, just a consistent insertion rule to maintain
* equivalence across rebalancings. Tie-breaking further than
* necessary simplifies testing a bit.
* 不需要完全的排序，只要插入的规则保持一致
*/
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;
}
/**
* Forms tree of the nodes linked from this node.
* @return root of tree 入参是一个TreeNode链表
*/
final void treeify(Node,V>[] tab) {
TreeNode,V> root = null;
// 遍历TreeNode链,TreeNode next
for (TreeNode,V> x = this, next; x != null; x = next) {
//把x的下一个节点给了next后，再单独取出x
next = (TreeNode,V>)x.next;
x.left = x.right = null;
//先设置root节点，颜色为黑色
if (root == null) {
x.parent = null;
x.red = false;
root = x;
}
else {
K k = x.key;
int h = x.hash;
Class kc = null;
//一个节点从根节点往下查询，直到相应位置为null则插入
for (TreeNode,V> p = root;;) {
int dir, ph;
K pk = p.key;
//这里根据父节点hash值与节点hash值得比较来确定节点插入（排序）的位置
//dir <= 0 插入左边，否则右边
if ((ph = p.hash) > h)
dir = -1;
else if (ph < h)
dir = 1;
else if ((kc == null &&
(kc = comparableClassFor(k)) == null) ||
(dir = compareComparables(kc, k, pk)) == 0)
//如果hash冲突了，那么就根据一致性hash来比较（不需要完全的排序）
dir = tieBreakOrder(k, pk);
TreeNode,V> xp = p;
if ((p = (dir <= 0) ? p.left : p.right) == null) {
x.parent = xp;
if (dir <= 0)
xp.left = x;
else
xp.right = x;
root = balanceInsertion(root, x);
break;
}
}
}
}
moveRootToFront(tab, root);
}
/**
* Returns a list of non-TreeNodes replacing those linked from
* this node.
*/
final Node,V> untreeify(HashMap,V> map) {
Node,V> hd = null, tl = null;
for (Node,V> q = this; q != null; q = q.next) {
Node,V> p = map.replacementNode(q, null);
if (tl == null)
hd = p;
else
tl.next = p;
tl = p;
}
return hd;
}
/**
* Tree version of putVal.
*/
final TreeNode,V> putTreeVal(HashMap,V> map, Node,V>[] tab,
int h, K k, V v) {
Class kc = null;
boolean searched = false;
TreeNode,V> root = (parent != null) ? root() : this;
for (TreeNode,V> 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,V> 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,V> xp = p;
if ((p = (dir <= 0) ? p.left : p.right) == null) {
Node,V> xpn = xp.next;
TreeNode,V> 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,V>)xpn).prev = x;
moveRootToFront(tab, balanceInsertion(root, x));
return null;
}
}
}
/**
* Removes the given node, that must be present before this call.
* This is messier than typical red-black deletion code because we
* cannot swap the contents of an interior node with a leaf
* successor that is pinned by "next" pointers that are accessible
* independently during traversal. So instead we swap the tree
* linkages. If the current tree appears to have too few nodes,
* the bin is converted back to a plain bin. (The test triggers
* somewhere between 2 and 6 nodes, depending on tree structure).
*/
/**
* 因为在hashMap中叶子节点不是哨兵，而是单纯的null，所以必须判断null的情况，
* 因此代码比叶子节点是哨兵的情况更复杂。
* 如果树的节点过少，将被转换为链表。
*
* this.removeTreeNode即为在该map中删除这个this节点
*/
final void removeTreeNode(HashMap,V> map, Node,V>[] tab,
boolean movable) {
int n;
if (tab == null || (n = tab.length) == 0)
return;
int index = (n - 1) & hash;
//桶的第一个即为root节点
TreeNode,V> first = (TreeNode,V>)tab[index], root = first, rl;
//succ为后继，pred为前驱 （0，1，2，3，4中，1位2的前驱，3位2的后继）
//后继节点必然在右子树中，且没有左孩子
TreeNode,V> succ = (TreeNode,V>)next, pred = prev;
//如果这个节点没有前驱，那么删除这个节点以后，直接把后继设置为第一个节点
if (pred == null)
tab[index] = first = succ;
//如果前驱存在，那么这个前驱的后继就直接变为succ
else
pred.next = succ;
/**
* 到这里可以看到，这里都是在处理删除节点以后，前驱、后继的关联关系
*/
if (succ != null)
succ.prev = pred;
if (first == null)
return;
if (root.parent != null)
root = root.root();
/**
* 如果树太小的话，就转为链表
*/
if (root == null || root.right == null ||
(rl = root.left) == null || rl.left == null) {
tab[index] = first.untreeify(map); // too small
return;
}
TreeNode,V> p = this, pl = left, pr = right, replacement;
/**
* 处理两个孩子节点都不为空的情况
*/
if (pl != null && pr != null) {
TreeNode,V> s = pr, sl;
//查找后继节点（即s）
while ((sl = s.left) != null) // find successor
s = sl;
//交换颜色
boolean c = s.red; s.red = p.red; p.red = c; // swap colors
TreeNode,V> sr = s.right;
TreeNode,V> pp = p.parent;
//如果p是后继节点的父节点,那就直接交换
if (s == pr) { // p was s's direct parent
p.parent = s;
s.right = p;
//如果p不是后继节点的父节点,
}else {
TreeNode,V> sp = s.parent;
//先将s节点（即后驱节点）替换为p(要删除的节点)
if ((p.parent = sp) != null) {
if (s == sp.left)
sp.left = p;
else
sp.right = p;
}
//将p节点替换为s节点，即p与s互换
if ((s.right = pr) != null)
pr.parent = s;
}
p.left = null;
//s与p互换以后，将sr的父节点设置为p
if ((p.right = sr) != null)
sr.parent = p;
//s与p互换以后，将pl的父节点设置为s
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;
//因为s是后继节点，所以sl是空的
//如果sr不是空节点，那么就用sr替换
if (sr != null)
replacement = sr;
//如果sr是空节点，那么就用p替换
else
replacement = p;
}
//如果p只有一个孩子的情况
else if (pl != null)
replacement = pl;
else if (pr != null)
replacement = pr;
//p没有孩子的情况
else
replacement = p;
//如果replacement不是p,那么就用replacement来替换p
//在第一种情况中（两个孩子），即sr替换p
if (replacement != p) {
TreeNode,V> 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;
}
//上面到此为止是二叉树的删除节点逻辑（详见《算法导论》181页，图12-4）
//这里开始红黑树的平衡，如果删除的节点是黑色，那么会导致红黑树性质的破坏
/**
* 如果p是红色不会破坏红黑树性质的原因：
* 1、树中的黑高没有变化
* 2、不会存在红色节点相邻的情况
* 3、如果p是红色，就不会是根节点，所以根节点依旧是黑色
*/
TreeNode,V> r = p.red ? root : balanceDeletion(root, replacement);
if (replacement == p) { // detach
TreeNode,V> 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);
}
/**
* Splits nodes in a tree bin into lower and upper tree bins,
* or untreeifies if now too small. Called only from resize;
* see above discussion about split bits and indices.
*
* @param map the map
* @param tab the table for recording bin heads
* @param index the index of the table being split
* @param bit the bit of hash to split on
*/
final void split(HashMap,V> map, Node,V>[] tab, int index, int bit) {
TreeNode,V> b = this;
// Relink into lo and hi lists, preserving order
TreeNode,V> loHead = null, loTail = null;
TreeNode,V> hiHead = null, hiTail = null;
int lc = 0, hc = 0;
for (TreeNode,V> e = b, next; e != null; e = next) {
next = (TreeNode,V>)e.next;
e.next = null;
if ((e.hash & bit) == 0) {
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;
}
}
if (loHead != null) {
if (lc <= UNTREEIFY_THRESHOLD)
tab[index] = loHead.untreeify(map);
else {
tab[index] = loHead;
if (hiHead != null) // (else is already treeified)
loHead.treeify(tab);
}
}
if (hiHead != null) {
if (hc <= UNTREEIFY_THRESHOLD)
tab[index + bit] = hiHead.untreeify(map);
else {
tab[index + bit] = hiHead;
if (loHead != null)
hiHead.treeify(tab);
}
}
}
/* ------------------------------------------------------------ */
// Red-black tree methods, all adapted from CLR
/**
* 左旋，即变成左节点
* 设p的右子为pr
* 以p为左旋，则p变成pr的左子，
* 且pr的左子变为p的右子
*/
static ,V> TreeNode,V> rotateLeft(TreeNode,V> root,
TreeNode,V> p) {
TreeNode,V> 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;
}
/**
* 右旋，即变成右节点
* 设p的左子为pl
* 以p为右旋，则p变成pl的右子，
* 且pl的右子变为p的左子
*/
static ,V> TreeNode,V> rotateRight(TreeNode,V> root,
TreeNode,V> p) {
TreeNode,V> 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;
}
/**
* 在treeify()方法中用到这个方法，该方法主要是维持红黑树的性质
* @param root 根节点
* @param x 要插入的节点
*
* 插入节点后，红黑树的性质可能被破坏，此时需要“对节点重新着色并旋转”来保持红黑树的性质
* 插入会破坏的红黑树性质有：1、根节点是黑色的 2、如果一个节点是红色的，那么它的两个子节点是黑色的
* 即根节点可能被插入为红色，或者红色节点相邻
*/
static ,V> TreeNode,V> balanceInsertion(TreeNode,V> root,
TreeNode,V> x) {
//新增节点默认是红色
x.red = true;
/**
* 假设插入的节点为左左情况，破坏的性质是红节点相邻，那么一次循环解决
* 以后，可能又会出现红色节点相邻的情况，因此需要循环来解决整个高度上
* 可能出现的连锁反应
*/
//循环整棵树节点,xp是x的父节点，xpp是xp的父节点
for (TreeNode,V> xp, xpp, xppl, xppr;;) {
//x的父节点如果不存在，说明x将是root节点，为黑色
if ((xp = x.parent) == null) {
x.red = false;
return x;
// xp为黑色节点 或 xp为根节点
// 那就不需要维持平衡了，已经平衡了，所以直接返回
}else if (!xp.red || (xpp = xp.parent) == null)
return root;
/**
* 插入节点有4种情况，即左左，左右，右左，右右
* 其中左左和右右、左右和右左处理的方式相同
*/
//当x是在左树的时候可能会遇到的问题处理
if (xp == (xppl = xpp.left)) {
/**
* 注意，由上面判断可以知道，如果xp是黑色，那么就不需要维护了，所以到这里来的时候，xp都是红色
* 这说明x的红色与xp的红色破坏了红色不能相邻的性质
*/
/**
* 这里分两种情况：
* 1、叔节点(xp的兄弟节点)是红色
* 2、叔节点不是红色
*/
if ((xppr = xpp.right) != null && xppr.red) {
//xp和叔节点、xpp节点变色，下次循环从xpp开始
xppr.red = false;
xp.red = false;
xpp.red = true;
x = xpp;
}else {
/**
* 叔节点是黑色又是左右的情况，则左旋
*/
if (x == xp.right) {
//左旋和右旋的目的是更改节点的指针指向，使其符合红黑树性质（降低树的高度）
root = rotateLeft(root, x = xp);
xpp = (xp = x.parent) == null ? null : xp.parent;
}
//左旋以后，如果发现xpp还为空的话，就右旋
if (xp != null) {
xp.red = false;
if (xpp != null) {
xpp.red = true;
root = rotateRight(root, xpp);
}
}
}
//当x是在右树的时候可能会遇到的问题处理————与上诉操作相反就可以了
} 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);
}
}
}
}
}
}
/**
* 删除节点的时候平衡
*/
static ,V> TreeNode,V> balanceDeletion(TreeNode,V> root,
TreeNode,V> x) {
for (TreeNode,V> 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;
//如果x是左孩子
}else if ((xpl = xp.left) == x) {
/**
* 这是情况一：
* 如果兄弟节点是红色，那么兄弟节点和父节点颜色互换
* 并且对父节点进行左旋
*/
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;
}
/**
* 如果没走上面的if逻辑，直接xpr是空的，说明不存在兄弟节点，可以直接删除x，不会引起红黑树性质冲突。
* 如果经过了上面的if逻辑，此时的xpr是经过左旋来的（即以前是x的兄弟节点的右孩子，经过左旋以后成了x的兄弟）,
* xpr此时是空的，那直接删除x也没事。
* 可以看到，只要兄弟节点是空的，那直接删除x就没问题。
*/
if (xpr == null)
x = xp;
//如果x的兄弟节点是存在的
else {
TreeNode,V> sl = xpr.left, sr = xpr.right;
/**
* 这是情况二：
* 如果x的兄弟节点的孩子要么都不存在，要么都为黑色
* 那么直接把x的兄弟变为红色
*/
if ((sr == null || !sr.red) &&
(sl == null || !sl.red)) {
xpr.red = true;
x = xp;
}else {
/**
* 这是情况三：
* 如果在 “x的兄弟节点可能都存在（可能存在一个） 或 可能都为红色（可能一个为红)”的情况下:
* 如果sr为空，那么说明sl存在，那就把sl变黑
* 如果sr存在并且是黑色，那么如果sl也存在，那就把sl变黑
* 并对x的兄弟节点右旋
*/
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;
}
//走这里的逻辑的时候，建议直接采用《算法导论》中图13-7 (c)中变换后的模型来代入
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;
}
}
//如果是x是右孩子，相似的处理方式
} 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,V> 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;
}
}
}
}
}
/**
* Recursive invariant check
*/
static ,V> boolean checkInvariants(TreeNode,V> t) {
TreeNode,V> tp = t.parent, tl = t.left, tr = t.right,
tb = t.prev, tn = (TreeNode,V>)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;
}
}
}
