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git-svn-id: http://code.alibabatech.com/svn/druid/trunk@9 b9813039-fb51-4c41-a8b9-e21c2acb5095
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wenshao
2011-05-11 06:44:20 +00:00
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src/main/java/com/alibaba/druid/util/IntHashMap.java
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/*
* Copyright 2011 Alibaba Group.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.druid.util;
import java.io.IOException;
import java.io.Serializable;
import java.util.AbstractCollection;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
public class IntHashMap<V> implements Map<Integer,V>, Cloneable, Serializable {
/**
* The default initial capacity - MUST be a power of two.
*/
static final int DEFAULT_INITIAL_CAPACITY = 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 table, resized as necessary. Length MUST Always be a power of two.
*/
transient Entry<V>[] table;
/**
* The number of key-value mappings contained in this map.
*/
transient int size;
/**
* The next size value at which to resize (capacity * load factor).
* @serial
*/
int threshold;
/**
* The load factor for the hash table.
*
* @serial
*/
final float loadFactor;
/**
* 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 volatile int modCount;
transient volatile Set<Integer> keySet = null;
transient volatile Collection<V> values = null;
/**
* Constructs an empty <tt>HashMap</tt> 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
*/
@SuppressWarnings("unchecked")
public IntHashMap(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);
// Find a power of 2 >= initialCapacity
int capacity = 1;
while (capacity < initialCapacity)
capacity <<= 1;
this.loadFactor = loadFactor;
threshold = (int)(capacity * loadFactor);
table = new Entry[capacity];
init();
}
/**
* Constructs an empty <tt>HashMap</tt> 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 IntHashMap(int initialCapacity) {
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
/**
* Constructs an empty <tt>HashMap</tt> with the default initial capacity
* (16) and the default load factor (0.75).
*/
@SuppressWarnings("unchecked")
public IntHashMap() {
this.loadFactor = DEFAULT_LOAD_FACTOR;
threshold = (int)(DEFAULT_INITIAL_CAPACITY * DEFAULT_LOAD_FACTOR);
table = new Entry[DEFAULT_INITIAL_CAPACITY];
init();
}
/**
* Constructs a new <tt>HashMap</tt> with the same mappings as the
* specified <tt>Map</tt>. The <tt>HashMap</tt> is created with
* default load factor (0.75) and an initial capacity sufficient to
* hold the mappings in the specified <tt>Map</tt>.
*
* @param m the map whose mappings are to be placed in this map
* @throws NullPointerException if the specified map is null
*/
public IntHashMap(Map<? extends Integer, ? extends V> m) {
this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR);
putAllForCreate(m);
}
// internal utilities
/**
* Initialization hook for subclasses. This method is called
* in all constructors and pseudo-constructors (clone, readObject)
* after HashMap has been initialized but before any entries have
* been inserted. (In the absence of this method, readObject would
* require explicit knowledge of subclasses.)
*/
void init() {
}
/**
* Applies a supplemental hash function to a given hashCode, which
* defends against poor quality hash functions. This is critical
* because HashMap uses power-of-two length hash tables, that
* otherwise encounter collisions for hashCodes that do not differ
* in lower bits. Note: Null keys always map to hash 0, thus index 0.
*/
/**
* Returns index for hash code h.
*/
static int indexFor(int h, int length) {
return h & (length-1);
}
/**
* 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 <tt>true</tt> if this map contains no key-value mappings.
*
* @return <tt>true</tt> 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.
*
* <p>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.)
*
* <p>A return value of {@code null} does not <i>necessarily</i>
* 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) {
return get(((Integer) key).intValue());
}
public V get(int key) {
int hash = key;
for (Entry<V> e = table[indexFor(hash, table.length)];
e != null;
e = e.next) {
if (e.hash == hash && e.key == key)
return e.value;
}
return null;
}
/**
* Returns <tt>true</tt> if this map contains a mapping for the
* specified key.
*
* @param key The key whose presence in this map is to be tested
* @return <tt>true</tt> if this map contains a mapping for the specified
* key.
*/
public boolean containsKey(Object key) {
return containsKey(((Integer)key).intValue());
}
public boolean containsKey(int key) {
return getEntry(key) != null;
}
/**
* Returns the entry associated with the specified key in the
* HashMap. Returns null if the HashMap contains no mapping
* for the key.
*/
final Entry<V> getEntry(int key) {
int hash = key;
for (Entry<V> e = table[indexFor(hash, table.length)];
e != null;
e = e.next) {
if (e.hash == hash && key == e.key)
return e;
}
return 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 <tt>key</tt>, or
* <tt>null</tt> if there was no mapping for <tt>key</tt>.
* (A <tt>null</tt> return can also indicate that the map
* previously associated <tt>null</tt> with <tt>key</tt>.)
*/
public V put(Integer key, V value) {
return put(key.intValue(), value);
}
public V put(int key, V value) {
int hash = key;
int i = indexFor(hash, table.length);
for (Entry<V> e = table[i]; e != null; e = e.next) {
if (e.hash == hash && (e.key == key)) {
V oldValue = e.value;
e.value = value;
return oldValue;
}
}
modCount++;
addEntry(hash, key, value, i);
return null;
}
/**
* This method is used instead of put by constructors and
* pseudoconstructors (clone, readObject). It does not resize the table,
* check for comodification, etc. It calls createEntry rather than
* addEntry.
*/
private void putForCreate(int key, V value) {
int hash = key;
int i = indexFor(hash, table.length);
/**
* Look for preexisting entry for key. This will never happen for
* clone or deserialize. It will only happen for construction if the
* input Map is a sorted map whose ordering is inconsistent w/ equals.
*/
for (Entry<V> e = table[i]; e != null; e = e.next) {
if (e.hash == hash && key == e.key) {
e.value = value;
return;
}
}
createEntry(hash, key, value, i);
}
private void putAllForCreate(Map<? extends Integer, ? extends V> m) {
for (Iterator<? extends Map.Entry<? extends Integer, ? extends V>> i = m.entrySet().iterator(); i.hasNext(); ) {
Map.Entry<? extends Integer, ? extends V> e = i.next();
putForCreate(e.getKey(), e.getValue());
}
}
/**
* Rehashes the contents of this map into a new array with a
* larger capacity. This method is called automatically when the
* number of keys in this map reaches its threshold.
*
* If current capacity is MAXIMUM_CAPACITY, this method does not
* resize the map, but sets threshold to Integer.MAX_VALUE.
* This has the effect of preventing future calls.
*
* @param newCapacity the new capacity, MUST be a power of two;
* must be greater than current capacity unless current
* capacity is MAXIMUM_CAPACITY (in which case value
* is irrelevant).
*/
@SuppressWarnings("unchecked")
void resize(int newCapacity) {
Entry<V>[] oldTable = table;
int oldCapacity = oldTable.length;
if (oldCapacity == MAXIMUM_CAPACITY) {
threshold = Integer.MAX_VALUE;
return;
}
Entry<V>[] newTable = new Entry[newCapacity];
transfer(newTable);
table = newTable;
threshold = (int)(newCapacity * loadFactor);
}
/**
* Transfers all entries from current table to newTable.
*/
void transfer(Entry<V>[] newTable) {
Entry<V>[] src = table;
int newCapacity = newTable.length;
for (int j = 0; j < src.length; j++) {
Entry<V> e = src[j];
if (e != null) {
src[j] = null;
do {
Entry<V> next = e.next;
int i = indexFor(e.hash, newCapacity);
e.next = newTable[i];
newTable[i] = e;
e = next;
} while (e != null);
}
}
}
/**
* 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(Map<? extends Integer, ? extends V> m) {
int numKeysToBeAdded = m.size();
if (numKeysToBeAdded == 0)
return;
/*
* Expand the map if the map if the number of mappings to be added
* is greater than or equal to threshold. This is conservative; the
* obvious condition is (m.size() + size) >= threshold, but this
* condition could result in a map with twice the appropriate capacity,
* if the keys to be added overlap with the keys already in this map.
* By using the conservative calculation, we subject ourself
* to at most one extra resize.
*/
if (numKeysToBeAdded > threshold) {
int targetCapacity = (int)(numKeysToBeAdded / loadFactor + 1);
if (targetCapacity > MAXIMUM_CAPACITY)
targetCapacity = MAXIMUM_CAPACITY;
int newCapacity = table.length;
while (newCapacity < targetCapacity)
newCapacity <<= 1;
if (newCapacity > table.length)
resize(newCapacity);
}
for (Iterator<? extends Map.Entry<? extends Integer, ? extends V>> i = m.entrySet().iterator(); i.hasNext(); ) {
Map.Entry<? extends Integer, ? extends V> e = i.next();
put(e.getKey(), e.getValue());
}
}
/**
* 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 <tt>key</tt>, or
* <tt>null</tt> if there was no mapping for <tt>key</tt>.
* (A <tt>null</tt> return can also indicate that the map
* previously associated <tt>null</tt> with <tt>key</tt>.)
*/
public V remove(Object key) {
return remove(((Integer) key).intValue());
}
public V remove(int key) {
Entry<V> e = removeEntryForKey(key);
return (e == null ? null : e.value);
}
/**
* Removes and returns the entry associated with the specified key
* in the HashMap. Returns null if the HashMap contains no mapping
* for this key.
*/
final Entry<V> removeEntryForKey(int key) {
int hash = key;
int i = indexFor(hash, table.length);
Entry<V> prev = table[i];
Entry<V> e = prev;
while (e != null) {
Entry<V> next = e.next;
if (e.hash == hash && key == e.key) {
modCount++;
size--;
if (prev == e)
table[i] = next;
else
prev.next = next;
return e;
}
prev = e;
e = next;
}
return e;
}
/**
* Special version of remove for EntrySet.
*/
@SuppressWarnings("unchecked")
final Entry<V> removeMapping(Object o) {
if (!(o instanceof Map.Entry))
return null;
Map.Entry<Integer,V> entry = (Map.Entry<Integer,V>) o;
int key = ((Integer)entry.getKey()).intValue();
int hash = key;
int i = indexFor(hash, table.length);
Entry<V> prev = table[i];
Entry<V> e = prev;
while (e != null) {
Entry<V> next = e.next;
if (e.hash == hash && e.equals(entry)) {
modCount++;
size--;
if (prev == e)
table[i] = next;
else
prev.next = next;
return e;
}
prev = e;
e = next;
}
return e;
}
/**
* Removes all of the mappings from this map.
* The map will be empty after this call returns.
*/
public void clear() {
modCount++;
Entry<V>[] tab = table;
for (int i = 0; i < tab.length; i++)
tab[i] = null;
size = 0;
}
/**
* Returns <tt>true</tt> 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 <tt>true</tt> if this map maps one or more keys to the
* specified value
*/
public boolean containsValue(Object value) {
if (value == null)
return containsNullValue();
Entry<V>[] tab = table;
for (int i = 0; i < tab.length ; i++)
for (Entry<V> e = tab[i] ; e != null ; e = e.next)
if (value.equals(e.value))
return true;
return false;
}
/**
* Special-case code for containsValue with null argument
*/
private boolean containsNullValue() {
Entry<V>[] tab = table;
for (int i = 0; i < tab.length ; i++)
for (Entry<V> e = tab[i] ; e != null ; e = e.next)
if (e.value == null)
return true;
return false;
}
/**
* Returns a shallow copy of this <tt>HashMap</tt> instance: the keys and
* values themselves are not cloned.
*
* @return a shallow copy of this map
*/
@SuppressWarnings("unchecked")
public Object clone() {
IntHashMap<V> result = null;
try {
result = (IntHashMap<V>)super.clone();
} catch (CloneNotSupportedException e) {
// assert false;
}
result.table = new Entry[table.length];
result.entrySet = null;
result.modCount = 0;
result.size = 0;
result.init();
result.putAllForCreate(this);
return result;
}
static class Entry<V> implements Map.Entry<Integer,V> {
final int key;
V value;
Entry<V> next;
final int hash;
/**
* Creates new entry.
*/
Entry(int h, int k, V v, Entry<V> n) {
value = v;
next = n;
key = k;
hash = h;
}
public final Integer getKey() {
return key;
}
public final int getIntKey() {
return key;
}
public final V getValue() {
return value;
}
public final V setValue(V newValue) {
V oldValue = value;
value = newValue;
return oldValue;
}
@SuppressWarnings("rawtypes")
public final boolean equals(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry e = (Map.Entry)o;
Object k1 = getKey();
Object k2 = e.getKey();
if (k1 == k2 || (k1 != null && k1.equals(k2))) {
Object v1 = getValue();
Object v2 = e.getValue();
if (v1 == v2 || (v1 != null && v1.equals(v2)))
return true;
}
return false;
}
public final int hashCode() {
return hash;
}
public final String toString() {
return getKey() + "=" + getValue();
}
}
/**
* Adds a new entry with the specified key, value and hash code to
* the specified bucket. It is the responsibility of this
* method to resize the table if appropriate.
*
* Subclass overrides this to alter the behavior of put method.
*/
void addEntry(int hash, Integer key, V value, int bucketIndex) {
Entry<V> e = table[bucketIndex];
table[bucketIndex] = new Entry<V>(hash, key, value, e);
if (size++ >= threshold)
resize(2 * table.length);
}
/**
* Like addEntry except that this version is used when creating entries
* as part of Map construction or "pseudo-construction" (cloning,
* deserialization). This version needn't worry about resizing the table.
*
* Subclass overrides this to alter the behavior of HashMap(Map),
* clone, and readObject.
*/
void createEntry(int hash, int key, V value, int bucketIndex) {
Entry<V> e = table[bucketIndex];
table[bucketIndex] = new Entry<V>(hash, key, value, e);
size++;
}
private abstract class HashIterator<E> implements Iterator<E> {
Entry<V> next; // next entry to return
int expectedModCount; // For fast-fail
int index; // current slot
Entry<V> current; // current entry
HashIterator() {
expectedModCount = modCount;
if (size > 0) { // advance to first entry
Entry<V>[] t = table;
while (index < t.length && (next = t[index++]) == null)
;
}
}
public final boolean hasNext() {
return next != null;
}
final Entry<V> nextEntry() {
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
Entry<V> e = next;
if (e == null)
throw new NoSuchElementException();
if ((next = e.next) == null) {
Entry<V>[] t = table;
while (index < t.length && (next = t[index++]) == null)
;
}
current = e;
return e;
}
public void remove() {
if (current == null)
throw new IllegalStateException();
if (modCount != expectedModCount)
throw new ConcurrentModificationException();
int k = current.key;
current = null;
IntHashMap.this.removeEntryForKey(k);
expectedModCount = modCount;
}
}
private final class ValueIterator extends HashIterator<V> {
public V next() {
return nextEntry().value;
}
}
private final class KeyIterator extends HashIterator<Integer> {
public Integer next() {
return nextEntry().getKey();
}
}
private final class EntryIterator extends HashIterator<Map.Entry<Integer,V>> {
public Map.Entry<Integer,V> next() {
return nextEntry();
}
}
// Subclass overrides these to alter behavior of views' iterator() method
Iterator<Integer> newKeyIterator() {
return new KeyIterator();
}
Iterator<V> newValueIterator() {
return new ValueIterator();
}
Iterator<Map.Entry<Integer,V>> newEntryIterator() {
return new EntryIterator();
}
// Views
private transient Set<Map.Entry<Integer,V>> entrySet = null;
/**
* 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 <tt>remove</tt> operation), the results of
* the iteration are undefined. The set supports element removal,
* which removes the corresponding mapping from the map, via the
* <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
* operations. It does not support the <tt>add</tt> or <tt>addAll</tt>
* operations.
*/
public Set<Integer> keySet() {
Set<Integer> ks = keySet;
return (ks != null ? ks : (keySet = new KeySet()));
}
private final class KeySet extends AbstractSet<Integer> {
public Iterator<Integer> iterator() {
return newKeyIterator();
}
public int size() {
return size;
}
public boolean contains(Object o) {
return containsKey(o);
}
public boolean remove(Object o) {
return IntHashMap.this.removeEntryForKey(((Integer)o).intValue()) != null;
}
public void clear() {
IntHashMap.this.clear();
}
}
/**
* 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 <tt>remove</tt> operation),
* the results of the iteration are undefined. The collection
* supports element removal, which removes the corresponding
* mapping from the map, via the <tt>Iterator.remove</tt>,
* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
* <tt>retainAll</tt> and <tt>clear</tt> operations. It does not
* support the <tt>add</tt> or <tt>addAll</tt> operations.
*/
public Collection<V> values() {
Collection<V> vs = values;
return (vs != null ? vs : (values = new Values()));
}
private final class Values extends AbstractCollection<V> {
public Iterator<V> iterator() {
return newValueIterator();
}
public int size() {
return size;
}
public boolean contains(Object o) {
return containsValue(o);
}
public void clear() {
IntHashMap.this.clear();
}
}
/**
* 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 <tt>remove</tt> operation, or through the
* <tt>setValue</tt> 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 <tt>Iterator.remove</tt>,
* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
* <tt>clear</tt> operations. It does not support the
* <tt>add</tt> or <tt>addAll</tt> operations.
*
* @return a set view of the mappings contained in this map
*/
public Set<Map.Entry<Integer,V>> entrySet() {
return entrySet0();
}
private Set<Map.Entry<Integer,V>> entrySet0() {
Set<Map.Entry<Integer,V>> es = entrySet;
return es != null ? es : (entrySet = new EntrySet());
}
private final class EntrySet extends AbstractSet<Map.Entry<Integer,V>> {
public Iterator<Map.Entry<Integer,V>> iterator() {
return newEntryIterator();
}
@SuppressWarnings("unchecked")
public boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry<Integer,V> e = (Map.Entry<Integer,V>) o;
Entry<V> candidate = getEntry(e.getKey());
return candidate != null && candidate.equals(e);
}
public boolean remove(Object o) {
return removeMapping(o) != null;
}
public int size() {
return size;
}
public void clear() {
IntHashMap.this.clear();
}
}
/**
* Save the state of the <tt>HashMap</tt> instance to a stream (i.e.,
* serialize it).
*
* @serialData The <i>capacity</i> of the HashMap (the length of the
* bucket array) is emitted (int), followed by the
* <i>size</i> (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
{
Iterator<Map.Entry<Integer,V>> i =
(size > 0) ? entrySet0().iterator() : null;
// Write out the threshold, loadfactor, and any hidden stuff
s.defaultWriteObject();
// Write out number of buckets
s.writeInt(table.length);
// Write out size (number of Mappings)
s.writeInt(size);
// Write out keys and values (alternating)
if (i != null) {
while (i.hasNext()) {
Map.Entry<Integer,V> e = i.next();
s.writeInt(e.getKey());
s.writeObject(e.getValue());
}
}
}
private static final long serialVersionUID = 362498820763181265L;
/**
* Reconstitute the <tt>HashMap</tt> instance from a stream (i.e.,
* deserialize it).
*/
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s)
throws IOException, ClassNotFoundException
{
// Read in the threshold, loadfactor, and any hidden stuff
s.defaultReadObject();
// Read in number of buckets and allocate the bucket array;
int numBuckets = s.readInt();
table = new Entry[numBuckets];
init(); // Give subclass a chance to do its thing.
// Read in size (number of Mappings)
int size = s.readInt();
// Read the keys and values, and put the mappings in the HashMap
for (int i=0; i<size; i++) {
int key = s.readInt();
V value = (V) s.readObject();
putForCreate(key, value);
}
}
// These methods are used when serializing HashSets
int capacity() { return table.length; }
float loadFactor() { return loadFactor; }
}
src/main/java/com/alibaba/druid/util/LongHashMap.java
-850
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@@ -1,850 +0,0 @@
/*
* Copyright 2011 Alibaba Group.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.druid.util;
import java.io.IOException;
import java.io.Serializable;
import java.util.AbstractCollection;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
public class LongHashMap<V> implements Map<Long, V>, Cloneable, Serializable {
/**
* The default initial capacity - MUST be a power of two.
*/
static final int DEFAULT_INITIAL_CAPACITY = 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 table, resized as necessary. Length MUST Always be a power of two.
*/
transient Entry<V>[] table;
/**
* The number of key-value mappings contained in this map.
*/
transient int size;
/**
* The next size value at which to resize (capacity * load factor).
*
* @serial
*/
int threshold;
/**
* The load factor for the hash table.
*
* @serial
*/
final float loadFactor;
/**
* 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 volatile int modCount;
transient volatile Set<Long> keySet = null;
transient volatile Collection<V> values = null;
/**
* Constructs an empty <tt>HashMap</tt> 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
*/
@SuppressWarnings("unchecked")
public LongHashMap(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);
// Find a power of 2 >= initialCapacity
int capacity = 1;
while (capacity < initialCapacity)
capacity <<= 1;
this.loadFactor = loadFactor;
threshold = (int) (capacity * loadFactor);
table = new Entry[capacity];
init();
}
/**
* Constructs an empty <tt>HashMap</tt> 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 LongHashMap(int initialCapacity){
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
/**
* Constructs an empty <tt>HashMap</tt> with the default initial capacity (16) and the default load factor (0.75).
*/
@SuppressWarnings("unchecked")
public LongHashMap(){
this.loadFactor = DEFAULT_LOAD_FACTOR;
threshold = (int) (DEFAULT_INITIAL_CAPACITY * DEFAULT_LOAD_FACTOR);
table = new Entry[DEFAULT_INITIAL_CAPACITY];
init();
}
/**
* Constructs a new <tt>HashMap</tt> with the same mappings as the specified <tt>Map</tt>. The <tt>HashMap</tt> is
* created with default load factor (0.75) and an initial capacity sufficient to hold the mappings in the specified
* <tt>Map</tt>.
*
* @param m the map whose mappings are to be placed in this map
* @throws NullPointerException if the specified map is null
*/
public LongHashMap(Map<? extends Long, ? extends V> m){
this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1, DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR);
putAllForCreate(m);
}
// internal utilities
/**
* Initialization hook for subclasses. This method is called in all constructors and pseudo-constructors (clone,
* readObject) after HashMap has been initialized but before any entries have been inserted. (In the absence of this
* method, readObject would require explicit knowledge of subclasses.)
*/
void init() {
}
/**
* Applies a supplemental hash function to a given hashCode, which defends against poor quality hash functions. This
* is critical because HashMap uses power-of-two length hash tables, that otherwise encounter collisions for
* hashCodes that do not differ in lower bits. Note: Null keys always map to hash 0, thus index 0.
*/
/**
* Returns index for hash code h.
*/
static int indexFor(int h, int length) {
return h & (length - 1);
}
/**
* 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 <tt>true</tt> if this map contains no key-value mappings.
*
* @return <tt>true</tt> 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.
* <p>
* 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.)
* <p>
* A return value of {@code null} does not <i>necessarily</i> 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) {
return get(((Long) key).intValue());
}
public V get(int key) {
int hash = key;
for (Entry<V> e = table[indexFor(hash, table.length)]; e != null; e = e.next) {
if (e.hash == hash && e.key == key) return e.value;
}
return null;
}
/**
* Returns <tt>true</tt> if this map contains a mapping for the specified key.
*
* @param key The key whose presence in this map is to be tested
* @return <tt>true</tt> if this map contains a mapping for the specified key.
*/
public boolean containsKey(Object key) {
return containsKey(((Long) key).intValue());
}
public boolean containsKey(int key) {
return getEntry(key) != null;
}
/**
* Returns the entry associated with the specified key in the HashMap. Returns null if the HashMap contains no
* mapping for the key.
*/
final Entry<V> getEntry(long key) {
int hash = hash(key);
for (Entry<V> e = table[indexFor(hash, table.length)]; e != null; e = e.next) {
if (e.hash == hash && key == e.key) return e;
}
return 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 <tt>key</tt>, or <tt>null</tt> if there was no mapping for
* <tt>key</tt>. (A <tt>null</tt> return can also indicate that the map previously associated <tt>null</tt> with
* <tt>key</tt>.)
*/
public V put(Long key, V value) {
return put(key.intValue(), value);
}
static int hash(long value) {
return (int) (value ^ (value >>> 32));
}
public V put(long key, V value) {
int hash = hash(key);
int i = indexFor(hash, table.length);
for (Entry<V> e = table[i]; e != null; e = e.next) {
if (e.hash == hash && (e.key == key)) {
V oldValue = e.value;
e.value = value;
return oldValue;
}
}
modCount++;
addEntry(hash, key, value, i);
return null;
}
/**
* This method is used instead of put by constructors and pseudoconstructors (clone, readObject). It does not resize
* the table, check for comodification, etc. It calls createEntry rather than addEntry.
*/
private void putForCreate(long key, V value) {
int hash = hash(key);
int i = indexFor(hash, table.length);
/**
* Look for preexisting entry for key. This will never happen for clone or deserialize. It will only happen for
* construction if the input Map is a sorted map whose ordering is inconsistent w/ equals.
*/
for (Entry<V> e = table[i]; e != null; e = e.next) {
if (e.hash == hash && key == e.key) {
e.value = value;
return;
}
}
createEntry(hash, key, value, i);
}
private void putAllForCreate(Map<? extends Long, ? extends V> m) {
for (Iterator<? extends Map.Entry<? extends Long, ? extends V>> i = m.entrySet().iterator(); i.hasNext();) {
Map.Entry<? extends Long, ? extends V> e = i.next();
putForCreate(e.getKey(), e.getValue());
}
}
/**
* Rehashes the contents of this map into a new array with a larger capacity. This method is called automatically
* when the number of keys in this map reaches its threshold. If current capacity is MAXIMUM_CAPACITY, this method
* does not resize the map, but sets threshold to Long.MAX_VALUE. This has the effect of preventing future calls.
*
* @param newCapacity the new capacity, MUST be a power of two; must be greater than current capacity unless current
* capacity is MAXIMUM_CAPACITY (in which case value is irrelevant).
*/
@SuppressWarnings("unchecked")
void resize(int newCapacity) {
Entry<V>[] oldTable = table;
int oldCapacity = oldTable.length;
if (oldCapacity == MAXIMUM_CAPACITY) {
threshold = Integer.MAX_VALUE;
return;
}
Entry<V>[] newTable = new Entry[newCapacity];
transfer(newTable);
table = newTable;
threshold = (int) (newCapacity * loadFactor);
}
/**
* Transfers all entries from current table to newTable.
*/
void transfer(Entry<V>[] newTable) {
Entry<V>[] src = table;
int newCapacity = newTable.length;
for (int j = 0; j < src.length; j++) {
Entry<V> e = src[j];
if (e != null) {
src[j] = null;
do {
Entry<V> next = e.next;
int i = indexFor(e.hash, newCapacity);
e.next = newTable[i];
newTable[i] = e;
e = next;
} while (e != null);
}
}
}
/**
* 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(Map<? extends Long, ? extends V> m) {
int numKeysToBeAdded = m.size();
if (numKeysToBeAdded == 0) return;
/*
* Expand the map if the map if the number of mappings to be added is greater than or equal to threshold. This
* is conservative; the obvious condition is (m.size() + size) >= threshold, but this condition could result in
* a map with twice the appropriate capacity, if the keys to be added overlap with the keys already in this map.
* By using the conservative calculation, we subject ourself to at most one extra resize.
*/
if (numKeysToBeAdded > threshold) {
int targetCapacity = (int) (numKeysToBeAdded / loadFactor + 1);
if (targetCapacity > MAXIMUM_CAPACITY) targetCapacity = MAXIMUM_CAPACITY;
int newCapacity = table.length;
while (newCapacity < targetCapacity)
newCapacity <<= 1;
if (newCapacity > table.length) resize(newCapacity);
}
for (Iterator<? extends Map.Entry<? extends Long, ? extends V>> i = m.entrySet().iterator(); i.hasNext();) {
Map.Entry<? extends Long, ? extends V> e = i.next();
put(e.getKey(), e.getValue());
}
}
/**
* 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 <tt>key</tt>, or <tt>null</tt> if there was no mapping for
* <tt>key</tt>. (A <tt>null</tt> return can also indicate that the map previously associated <tt>null</tt> with
* <tt>key</tt>.)
*/
public V remove(Object key) {
return remove(((Long) key).intValue());
}
public V remove(int key) {
Entry<V> e = removeEntryForKey(key);
return (e == null ? null : e.value);
}
/**
* Removes and returns the entry associated with the specified key in the HashMap. Returns null if the HashMap
* contains no mapping for this key.
*/
final Entry<V> removeEntryForKey(long key) {
int hash = hash(key);
int i = indexFor(hash, table.length);
Entry<V> prev = table[i];
Entry<V> e = prev;
while (e != null) {
Entry<V> next = e.next;
if (e.hash == hash && key == e.key) {
modCount++;
size--;
if (prev == e) table[i] = next;
else prev.next = next;
return e;
}
prev = e;
e = next;
}
return e;
}
/**
* Special version of remove for EntrySet.
*/
@SuppressWarnings("unchecked")
final Entry<V> removeMapping(Object o) {
if (!(o instanceof Map.Entry)) return null;
Map.Entry<Long, V> entry = (Map.Entry<Long, V>) o;
int key = ((Long) entry.getKey()).intValue();
int hash = key;
int i = indexFor(hash, table.length);
Entry<V> prev = table[i];
Entry<V> e = prev;
while (e != null) {
Entry<V> next = e.next;
if (e.hash == hash && e.equals(entry)) {
modCount++;
size--;
if (prev == e) table[i] = next;
else prev.next = next;
return e;
}
prev = e;
e = next;
}
return e;
}
/**
* Removes all of the mappings from this map. The map will be empty after this call returns.
*/
public void clear() {
modCount++;
Entry<V>[] tab = table;
for (int i = 0; i < tab.length; i++)
tab[i] = null;
size = 0;
}
/**
* Returns <tt>true</tt> 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 <tt>true</tt> if this map maps one or more keys to the specified value
*/
public boolean containsValue(Object value) {
if (value == null) return containsNullValue();
Entry<V>[] tab = table;
for (int i = 0; i < tab.length; i++)
for (Entry<V> e = tab[i]; e != null; e = e.next)
if (value.equals(e.value)) return true;
return false;
}
/**
* Special-case code for containsValue with null argument
*/
private boolean containsNullValue() {
Entry<V>[] tab = table;
for (int i = 0; i < tab.length; i++)
for (Entry<V> e = tab[i]; e != null; e = e.next)
if (e.value == null) return true;
return false;
}
/**
* Returns a shallow copy of this <tt>HashMap</tt> instance: the keys and values themselves are not cloned.
*
* @return a shallow copy of this map
*/
@SuppressWarnings("unchecked")
public Object clone() {
LongHashMap<V> result = null;
try {
result = (LongHashMap<V>) super.clone();
} catch (CloneNotSupportedException e) {
// assert false;
}
result.table = new Entry[table.length];
result.entrySet = null;
result.modCount = 0;
result.size = 0;
result.init();
result.putAllForCreate(this);
return result;
}
static class Entry<V> implements Map.Entry<Long, V> {
final long key;
V value;
Entry<V> next;
final int hash;
/**
* Creates new entry.
*/
Entry(int h, long k, V v, Entry<V> n){
value = v;
next = n;
key = k;
hash = h;
}
public final Long getKey() {
return key;
}
public final long getIntKey() {
return key;
}
public final V getValue() {
return value;
}
public final V setValue(V newValue) {
V oldValue = value;
value = newValue;
return oldValue;
}
@SuppressWarnings("rawtypes")
public final boolean equals(Object o) {
if (!(o instanceof Map.Entry)) return false;
Map.Entry e = (Map.Entry) o;
Object k1 = getKey();
Object k2 = e.getKey();
if (k1 == k2 || (k1 != null && k1.equals(k2))) {
Object v1 = getValue();
Object v2 = e.getValue();
if (v1 == v2 || (v1 != null && v1.equals(v2))) return true;
}
return false;
}
public final int hashCode() {
return hash;
}
public final String toString() {
return getKey() + "=" + getValue();
}
}
/**
* Adds a new entry with the specified key, value and hash code to the specified bucket. It is the responsibility of
* this method to resize the table if appropriate. Subclass overrides this to alter the behavior of put method.
*/
void addEntry(int hash, Long key, V value, int bucketIndex) {
Entry<V> e = table[bucketIndex];
table[bucketIndex] = new Entry<V>(hash, key, value, e);
if (size++ >= threshold) resize(2 * table.length);
}
/**
* Like addEntry except that this version is used when creating entries as part of Map construction or
* "pseudo-construction" (cloning, deserialization). This version needn't worry about resizing the table. Subclass
* overrides this to alter the behavior of HashMap(Map), clone, and readObject.
*/
void createEntry(int hash, long key, V value, int bucketIndex) {
Entry<V> e = table[bucketIndex];
table[bucketIndex] = new Entry<V>(hash, key, value, e);
size++;
}
private abstract class HashIterator<E> implements Iterator<E> {
Entry<V> next; // next entry to return
int expectedModCount; // For fast-fail
int index; // current slot
Entry<V> current; // current entry
HashIterator(){
expectedModCount = modCount;
if (size > 0) { // advance to first entry
Entry<V>[] t = table;
while (index < t.length && (next = t[index++]) == null)
;
}
}
public final boolean hasNext() {
return next != null;
}
final Entry<V> nextEntry() {
if (modCount != expectedModCount) throw new ConcurrentModificationException();
Entry<V> e = next;
if (e == null) throw new NoSuchElementException();
if ((next = e.next) == null) {
Entry<V>[] t = table;
while (index < t.length && (next = t[index++]) == null)
;
}
current = e;
return e;
}
public void remove() {
if (current == null) throw new IllegalStateException();
if (modCount != expectedModCount) throw new ConcurrentModificationException();
long k = current.key;
current = null;
LongHashMap.this.removeEntryForKey(k);
expectedModCount = modCount;
}
}
private final class ValueIterator extends HashIterator<V> {
public V next() {
return nextEntry().value;
}
}
private final class KeyIterator extends HashIterator<Long> {
public Long next() {
return nextEntry().getKey();
}
}
private final class EntryIterator extends HashIterator<Map.Entry<Long, V>> {
public Map.Entry<Long, V> next() {
return nextEntry();
}
}
// Subclass overrides these to alter behavior of views' iterator() method
Iterator<Long> newKeyIterator() {
return new KeyIterator();
}
Iterator<V> newValueIterator() {
return new ValueIterator();
}
Iterator<Map.Entry<Long, V>> newEntryIterator() {
return new EntryIterator();
}
// Views
private transient Set<Map.Entry<Long, V>> entrySet = null;
/**
* 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 <tt>remove</tt> operation), the results of the iteration are undefined. The
* set supports element removal, which removes the corresponding mapping from the map, via the
* <tt>Iterator.remove</tt>, <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
* operations. It does not support the <tt>add</tt> or <tt>addAll</tt> operations.
*/
public Set<Long> keySet() {
Set<Long> ks = keySet;
return (ks != null ? ks : (keySet = new KeySet()));
}
private final class KeySet extends AbstractSet<Long> {
public Iterator<Long> iterator() {
return newKeyIterator();
}
public int size() {
return size;
}
public boolean contains(Object o) {
return containsKey(o);
}
public boolean remove(Object o) {
return LongHashMap.this.removeEntryForKey(((Long) o).intValue()) != null;
}
public void clear() {
LongHashMap.this.clear();
}
}
/**
* 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 <tt>remove</tt> operation), the results of
* the iteration are undefined. The collection supports element removal, which removes the corresponding mapping
* from the map, via the <tt>Iterator.remove</tt>, <tt>Collection.remove</tt>, <tt>removeAll</tt>,
* <tt>retainAll</tt> and <tt>clear</tt> operations. It does not support the <tt>add</tt> or <tt>addAll</tt>
* operations.
*/
public Collection<V> values() {
Collection<V> vs = values;
return (vs != null ? vs : (values = new Values()));
}
private final class Values extends AbstractCollection<V> {
public Iterator<V> iterator() {
return newValueIterator();
}
public int size() {
return size;
}
public boolean contains(Object o) {
return containsValue(o);
}
public void clear() {
LongHashMap.this.clear();
}
}
/**
* 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 <tt>remove</tt> operation, or through the <tt>setValue</tt> 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 <tt>Iterator.remove</tt>,
* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and <tt>clear</tt> operations. It does not support
* the <tt>add</tt> or <tt>addAll</tt> operations.
*
* @return a set view of the mappings contained in this map
*/
public Set<Map.Entry<Long, V>> entrySet() {
return entrySet0();
}
private Set<Map.Entry<Long, V>> entrySet0() {
Set<Map.Entry<Long, V>> es = entrySet;
return es != null ? es : (entrySet = new EntrySet());
}
private final class EntrySet extends AbstractSet<Map.Entry<Long, V>> {
public Iterator<Map.Entry<Long, V>> iterator() {
return newEntryIterator();
}
@SuppressWarnings("unchecked")
public boolean contains(Object o) {
if (!(o instanceof Map.Entry)) return false;
Map.Entry<Long, V> e = (Map.Entry<Long, V>) o;
Entry<V> candidate = getEntry(e.getKey());
return candidate != null && candidate.equals(e);
}
public boolean remove(Object o) {
return removeMapping(o) != null;
}
public int size() {
return size;
}
public void clear() {
LongHashMap.this.clear();
}
}
/**
* Save the state of the <tt>HashMap</tt> instance to a stream (i.e., serialize it).
*
* @serialData The <i>capacity</i> of the HashMap (the length of the bucket array) is emitted (int), followed by the
* <i>size</i> (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 {
Iterator<Map.Entry<Long, V>> i = (size > 0) ? entrySet0().iterator() : null;
// Write out the threshold, loadfactor, and any hidden stuff
s.defaultWriteObject();
// Write out number of buckets
s.writeInt(table.length);
// Write out size (number of Mappings)
s.writeInt(size);
// Write out keys and values (alternating)
if (i != null) {
while (i.hasNext()) {
Map.Entry<Long, V> e = i.next();
s.writeLong(e.getKey());
s.writeObject(e.getValue());
}
}
}
private static final long serialVersionUID = 362498820763181265L;
/**
* Reconstitute the <tt>HashMap</tt> instance from a stream (i.e., deserialize it).
*/
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s) throws IOException, ClassNotFoundException {
// Read in the threshold, loadfactor, and any hidden stuff
s.defaultReadObject();
// Read in number of buckets and allocate the bucket array;
int numBuckets = s.readInt();
table = new Entry[numBuckets];
init(); // Give subclass a chance to do its thing.
// Read in size (number of Mappings)
int size = s.readInt();
// Read the keys and values, and put the mappings in the HashMap
for (int i = 0; i < size; i++) {
int key = s.readInt();
V value = (V) s.readObject();
putForCreate(key, value);
}
}
// These methods are used when serializing HashSets
int capacity() {
return table.length;
}
float loadFactor() {
return loadFactor;
}
}