Java源码阅读之HashMap
Summary：
- public class HashMap
- 桶数：预计元素个数的75%-150%；桶数设为一个素数，以防集聚,因为素数的分布似乎毫无规律, 总的来看很稀疏,偶尔有集聚现象；标准库桶数为2的幂，默认16
- 填装因子：决定何时对散列表进行再散列；默认使用双倍的桶数自动进行再散列，标准库默认使用0.75；
- 每个列表称为一个桶，列表Node数组实现；而对于桶中的元素可能是链表结构也可能是红黑树结构，根据桶中拥有的元素不同而定
Fields：
属于类的域
// aka 16；默认容量大小；容量必须是2的幂，
// why? 因为每个元素应该放置到哪个桶由hash(key)&n-1决定的；
//如果n是2的幂，那么n-1必然是一串11111..111；这样我们利用&运算就达到了取余的效果；这样效率是很高的
static final int DEFAULT_INITIAL_CAPACITY = 1 << 4;
//Node数组的最大容量int是32位的，最高位是符号位，所以得到了下面的最大值
static final int MAXIMUM_CAPACITY = 1 << 30;
//填装因子
static final float DEFAULT_LOAD_FACTOR = 0.75f;
//当桶中数据大于该值，则需要考虑将该桶中的元素转换成TreeNode
static final int TREEIFY_THRESHOLD = 8;
//当红黑树中的元素小于该值时，则将红黑树中的数据转换成普通链表形式存储，TreeNode的split中会用到
static final int UNTREEIFY_THRESHOLD = 6;
//将桶中的数据转换为TreeNode的时候，node数组所要求的最小的长度值
//MIN_TREEIFY_CAPACITY不应该小于4 * TREEIFY_THRESHOLD；为何是4倍暂时没想明白？
static final int MIN_TREEIFY_CAPACITY = 64;属于对象的域
//HashMap对象维护的Node数组
transient Node[] table;
transient Set> entrySet;//在entrySet方法中会用到
transient int size; //当前存储数据大小,而非node数组的长度
transient int modCount; //修改次数 在迭代器中会被使用
int threshold; //桶数的警戒值=桶的最大值*loadFactor
final float loadFactor; //填装因子 Constructor：
//默认初始容量16，载入因子0.75
public HashMap() {
this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
}
//初始容量initialCapacity，使用方法tableSizeFor进行设置，载入因子loadFactor
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);//tableSizeFor是确保了容量是2的幂，猜测数据结构跟树有关
}tableSizeFor()
//将cap自动地转换为不大于n的一个最近的2的幂
static final int tableSizeFor(int cap) {
int n = cap - 1;
n |= n >>> 1;
n |= n >>> 2;
n |= n >>> 4;
n |= n >>> 8; //到这里整数的高八位或者第八位应该全为1，或者全为0
n |= n >>> 16;
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
}size():
public int size() {
return size;
}isEmpty():
public boolean isEmpty() {
return size == 0;
}hash():
//获取当前对象key的hash值
//返回的值受对象的hashCode()方法影响
static final int hash(Object key) {
int h;
return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
}put(K key,V value):
public V put(K key, V value) {
return putVal(hash(key), key, value, false, true);
}putVal():
//内部调用的方法有：
//afterNodeInsertion(evict);插入的数据是所在桶的第一个数据（当前类不实现）
//afterNodeAccess(e);对新插入点进行访问过后（当前类不实现）
//resize();当前HashMap对象的数据大于threshold，或第一次初始化Node[] table的时候
//treeifyBin();插入的桶是普通Node，且插入后的元素大于成树的最小门限，即TREEIFY_THRESHOLD
//TreeNode.putTreeVal();插入的桶是TreeNode的时候
final V putVal(int hash, K key, V value, boolean onlyIfAbsent,boolean evict) {
Node[] tab;
Node p;
int n, i;
//n存储tab的大小，等于桶数
if ((tab = table) == null || (n = tab.length) == 0)
n = (tab = resize()).length;
//桶数-1&key的hash值就是对应的散列值，数组的下标；下标结果不会大于n-1
if ((p = tab[i = (n - 1) & hash]) == null)
tab[i] = newNode(hash, key, value, null);//桶中还未存入数据，则直接创建一个Node即可
//当前桶中已经存有数据了
else {
Node e;
K k;
//p指向当前的桶
if (p.hash == hash &&
((k = p.key) == key || (key != null && key.equals(k))))
e = p;
else if (p instanceof TreeNode)
e = ((TreeNode)p).putTreeVal(this, tab, hash, key, value); //节点是TreeNode类型，则调用该类型的方法存入数据
else {
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
treeifyBin(tab, hash); //参数为对象的node数组和插入数据的hash值
break;
}//end of if
if (e.hash == hash &&
((k = e.key) == key || (key != null && key.equals(k))))
break;
p = e;
}//end of for；
}//end of else(inner)
//上面运行的结果就是e指向的Node其key等于要插入的数据的key
if (e != null) { // existing mapping for key 更新旧值
V oldValue = e.value;
if (!onlyIfAbsent || oldValue == null) //如果onlyIfAbsent是true则不更新旧值，默认是false
e.value = value;
afterNodeAccess(e);
return oldValue;
}//end of if
}end of else(outside)
++modCount;
if (++size > threshold)
resize();//如果当前存储数据大于大于门限值，需要扩容
afterNodeInsertion(evict);
return null;
}
回调方法：
// Callbacks to allow LinkedHashMap post-actions
void afterNodeAccess(Node p) { }
void afterNodeInsertion(boolean evict) { }
void afterNodeRemoval(Node p) { }
扩容：resize()
//Initializes or doubles table size
//对原来的node数组进行扩容
//新建的node数组其大小等于原数组大小的两倍，相应的门限也变成原来的两倍；
//oldnode[j]中的数据会被分到newnode[j]或者newnode[j+oldnode.length]中根据数据的hash值具体确定
final Node[] resize() {
Node[] oldTab = table;
int oldCap = (oldTab == null) ? 0 : oldTab.length; //原表的桶数
int oldThr = threshold; //原表的桶数的警戒值，这里自然是小于桶数的
int newCap, newThr = 0;
if (oldCap > 0) {
if (oldCap >= MAXIMUM_CAPACITY) {
threshold = Integer.MAX_VALUE;
return oldTab;
}//对于这种情况已经无能为力，只能扩大下桶的警戒值
else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
oldCap >= DEFAULT_INITIAL_CAPACITY)
newThr = oldThr << 1; // double threshold
}//end of if
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);
}//end of else
//上面的代码对newCap和newThr进行了初始化；大多数情况是将原桶数和原桶的门限扩大两倍
if (newThr == 0) {
float ft = (float)newCap * loadFactor;
newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
(int)ft : Integer.MAX_VALUE);
}//end of if
threshold = newThr;//更新对象中的threshold域
@SuppressWarnings({"rawtypes","unchecked"})
Node[] newTab = (Node[])new Node[newCap]; //创建一个新的大小为newCap的Node数组
table = newTab; //更新当前对象中的table域
if (oldTab != null) {
for (int j = 0; j < oldCap; ++j) {
Node 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)e).split(this, newTab, j, oldCap);// 调用TreeNode.split方法进行对原桶中的数据进行分离
else { // preserve order
Node loHead = null, loTail = null;
Node hiHead = null, hiTail = null;
Node next;
do {
next = e.next;
if ((e.hash & oldCap) == 0) {
//以前的索引是hash跟oldCap-1相与；这一次则是与oldCap相与
if (loTail == null)
loHead = e;
else
loTail.next = e;
loTail = e;
}//落在0~oldCap-1之间的数
else {
if (hiTail == null)
hiHead = e;
else
hiTail.next = e;
hiTail = e;
}//落在oldCap~newCap-1之间的数
} while ((e = next) != null);
if (loTail != null) {
loTail.next = null;
newTab[j] = loHead;
}
if (hiTail != null) {
hiTail.next = null;
newTab[j + oldCap] = hiHead;
}
}//end of else
}end of if ((e = oldTab[j]) != null)
}end of for
}end of if (oldTab != null) 如果oldTab为null证明是第一次调用resize()只要创建一个Node数组即可
return newTab;
} treeifyBin():
final void treeifyBin(Node[] tab, int hash) {
int n, index;
Node e;
if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)//如果当前的node数组的长度小于MIN_TREEIFY_CAPACITY
resize();
else if ((e = tab[index = (n - 1) & hash]) != null) {
TreeNode hd = null, tl = null;
do {
TreeNode p = replacementTreeNode(e, null);
if (tl == null)
hd = p;
else {
p.prev = tl;
tl.next = p;
}
tl = p;
} while ((e = e.next) != null);
if ((tab[index] = hd) != null)
hd.treeify(tab);
}
} TreeNode replacementTreeNode(Node p, Node next) {
return new TreeNode<>(p.hash, p.key, p.value, next);
} get(Object key):
public boolean containsKey(Object key) {
return getNode(hash(key), key) != null;
}
public V get(Object key) {
Node e;
return (e = getNode(hash(key), key)) == null ? null : e.value;
}
//first = tab[(n-1)&hash]???
//TreeNode????
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 && ((k = first.key) == key || (key != null && key.equals(k))))
return first;
if ((e = first.next) != null) {
if (first instanceof TreeNode)
return ((TreeNode)first).getTreeNode(hash, key); //桶中的元素如果红黑树，则利用红黑树的方式查找
do {
if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k)))) //如果桶中的元素只是普通的链表，则从头往后一个一个的进行查找，最坏O(n)
return e;
} while ((e = e.next) != null);
}
}
return null;
} remove():
public V remove(Object key) {
Node e;
return (e = removeNode(hash(key), key, null, false, true)) == null ?
null : e.value;
}
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))))
node = p;
else if ((e = p.next) != null) {
if (p instanceof TreeNode)
node = ((TreeNode)p).getTreeNode(hash, key);
else {
do {
if (e.hash == hash &&
((k = e.key) == key ||
(key != null && key.equals(k)))) {
node = e;
break;
}
p = e;
} while ((e = e.next) != null);
}//end of else
}end of else if
//上面的代码用于寻找要删除的Node由node指向；操作与get(Object key)类似
if (node != null && (!matchValue || (v = node.value) == value ||
(value != null && value.equals(v)))) {
if (node instanceof TreeNode)
((TreeNode)node).removeTreeNode(this, tab, movable);
else if (node == p)
tab[index] = node.next;
else
p.next = node.next;
++modCount;
--size;
afterNodeRemoval(node);
return node;
}//end of if(inner)
}//end of if(outer)
return null;
} clear():
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;
}
} containsValue():
//这里没有将节点分为TreeNode还是普通Node；
//全部看成普通Node；从第一个桶的第一个元素一路next去比较；
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;
}
newNode():
Node newNode(int hash, K key, V value, Node next) {
return new Node<>(hash, key, value, next);
}
newTreeNode():
TreeNode newTreeNode(int hash, K key, V value, Node next) {
return new TreeNode<>(hash, key, value, next);
} 内部类Node
static class Node implements Map.Entry {
final int hash;
final K key;
V value;
Node next;
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; }
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;
}
}
内部类TreeNode
//注意LinkedHashMap.Entry extends HashMap.Node;TreeNode是Node的子类
//红黑树节点
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);
}
/**
* Returns root of tree containing this node.
*/
final TreeNode root() {
for (TreeNode 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 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) {
Node rn;
tab[index] = root;
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;
}
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.
*/
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;
}
/**
* Calls find for root node.
*/
final TreeNode 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.
*/
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
*/
final void treeify(Node[] tab) {
TreeNode root = null;
for (TreeNode x = this, next; x != null; x = next) {
next = (TreeNode)x.next;
x.left = x.right = null;
if (root == null) {
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;
K pk = p.key;
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)
dir = tieBreakOrder(k, pk);
TreeNode 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;
}//end of if
}//end of for
}'//end of else
}end of for
moveRootToFront(tab, root);
}
/**
* Returns a list of non-TreeNodes replacing those linked from
* this node.
*/
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;
}
/**
* Tree version of putVal.
*/
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 || (pk != 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;
}
}
}
/**
* 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).
*/
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);
}
/**
* 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 map, Node[] tab, int index, int bit) {
TreeNode b = this;
// 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;
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
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;
}
}
}
}
}
/**
* Recursive invariant check
*/
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;
}
}