/*
* JBoss, Home of Professional Open Source.
* Copyright 2011, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.as.controller.registry;
import java.io.IOException;
import java.io.Serializable;
import java.util.AbstractCollection;
import java.util.AbstractMap;
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;
import org.jboss.as.controller.logging.ControllerLogger;
/**
* A HashMap that is optimized for fast shallow copies. If the copy-ctor is
* passed another FastCopyHashMap, or clone is called on this map, the shallow
* copy can be performed using little more than a single array copy. In order to
* accomplish this, immutable objects must be used internally, so update
* operations result in slightly more object churn than <code>HashMap</code>.
* <p/>
* Note: It is very important to use a smaller load factor than you normally
* would for HashMap, since the implementation is open-addressed with linear
* probing. With a 50% load-factor a get is expected to return in only 2 probes.
* However, a 90% load-factor is expected to return in around 50 probes.
*
* @author Jason T. Greene
*/
class FastCopyHashMap<K, V> extends AbstractMap<K, V> implements Map<K, V>, Cloneable, Serializable {
/**
* Marks null keys.
*/
private static final Object NULL = new Object();
/**
* Serialization ID
*/
private static final long serialVersionUID = 10929568968762L;
/**
* Same default as HashMap, must be a power of 2
*/
private static final int DEFAULT_CAPACITY = 8;
/**
* MAX_INT - 1
*/
private static final int MAXIMUM_CAPACITY = 1 << 30;
/**
* 67%, just like IdentityHashMap
*/
private static final float DEFAULT_LOAD_FACTOR = 0.67f;
/**
* The open-addressed table
*/
private transient Entry<K, V>[] table;
/**
* The current number of key-value pairs
*/
private transient int size;
/**
* The next resize
*/
private transient int threshold;
/**
* The user defined load factor which defines when to resize
*/
private final float loadFactor;
/**
* Counter used to detect changes made outside of an iterator
*/
private transient int modCount;
// Cached views
private transient KeySet keySet;
private transient Values values;
private transient EntrySet entrySet;
public FastCopyHashMap(int initialCapacity, float loadFactor) {
if (initialCapacity < 0)
throw ControllerLogger.ROOT_LOGGER.invalidTableSize();
if (initialCapacity > MAXIMUM_CAPACITY)
initialCapacity = MAXIMUM_CAPACITY;
if (!(loadFactor > 0F && loadFactor <= 1F))
throw ControllerLogger.ROOT_LOGGER.invalidLoadFactor();
this.loadFactor = loadFactor;
init(initialCapacity, loadFactor);
}
@SuppressWarnings("unchecked")
public FastCopyHashMap(Map<? extends K, ? extends V> map) {
if (map instanceof FastCopyHashMap) {
FastCopyHashMap<? extends K, ? extends V> fast = (FastCopyHashMap<? extends K, ? extends V>) map;
this.table = (Entry<K, V>[]) fast.table.clone();
this.loadFactor = fast.loadFactor;
this.size = fast.size;
this.threshold = fast.threshold;
} else {
this.loadFactor = DEFAULT_LOAD_FACTOR;
init(map.size(), this.loadFactor);
putAll(map);
}
}
@SuppressWarnings("unchecked")
private void init(int initialCapacity, float loadFactor) {
int c = 1;
while (c < initialCapacity) c <<= 1;
threshold = (int) (c * loadFactor);
// Include the load factor when sizing the table for the first time
if (initialCapacity > threshold && c < MAXIMUM_CAPACITY) {
c <<= 1;
threshold = (int) (c * loadFactor);
}
this.table = (Entry<K, V>[]) new Entry[c];
}
public FastCopyHashMap(int initialCapacity) {
this(initialCapacity, DEFAULT_LOAD_FACTOR);
}
public FastCopyHashMap() {
this(DEFAULT_CAPACITY);
}
// The normal bit spreader...
private static int hash(Object key) {
int h = key.hashCode();
h ^= (h >>> 20) ^ (h >>> 12);
return h ^ (h >>> 7) ^ (h >>> 4);
}
@SuppressWarnings("unchecked")
private static <K> K maskNull(K key) {
return key == null ? (K) NULL : key;
}
private static <K> K unmaskNull(K key) {
return key == NULL ? null : key;
}
private int nextIndex(int index, int length) {
index = (index >= length - 1) ? 0 : index + 1;
return index;
}
private static boolean eq(Object o1, Object o2) {
return o1 == o2 || (o1 != null && o1.equals(o2));
}
private static int index(int hashCode, int length) {
return hashCode & (length - 1);
}
public int size() {
return size;
}
public boolean isEmpty() {
return size == 0;
}
public V get(Object key) {
key = maskNull(key);
int hash = hash(key);
int length = table.length;
int index = index(hash, length);
for (int start = index; ;) {
Entry<K, V> e = table[index];
if (e == null)
return null;
if (e.hash == hash && eq(key, e.key))
return e.value;
index = nextIndex(index, length);
if (index == start) // Full table
return null;
}
}
public boolean containsKey(Object key) {
key = maskNull(key);
int hash = hash(key);
int length = table.length;
int index = index(hash, length);
for (int start = index; ;) {
Entry<K, V> e = table[index];
if (e == null)
return false;
if (e.hash == hash && eq(key, e.key))
return true;
index = nextIndex(index, length);
if (index == start) // Full table
return false;
}
}
public boolean containsValue(Object value) {
for (Entry<K, V> e : table)
if (e != null && eq(value, e.value))
return true;
return false;
}
public V put(K key, V value) {
key = maskNull(key);
Entry<K, V>[] table = this.table;
int hash = hash(key);
int length = table.length;
int index = index(hash, length);
for (int start = index; ;) {
Entry<K, V> e = table[index];
if (e == null)
break;
if (e.hash == hash && eq(key, e.key)) {
table[index] = new Entry<K, V>(e.key, e.hash, value);
return e.value;
}
index = nextIndex(index, length);
if (index == start)
throw ControllerLogger.ROOT_LOGGER.tableIsFull();
}
modCount++;
table[index] = new Entry<K, V>(key, hash, value);
if (++size >= threshold)
resize(length);
return null;
}
@SuppressWarnings("unchecked")
private void resize(int from) {
int newLength = from << 1;
// Can't get any bigger
if (newLength > MAXIMUM_CAPACITY || newLength <= from)
return;
Entry<K, V>[] newTable = new Entry[newLength];
Entry<K, V>[] old = table;
for (Entry<K, V> e : old) {
if (e == null)
continue;
int index = index(e.hash, newLength);
while (newTable[index] != null)
index = nextIndex(index, newLength);
newTable[index] = e;
}
threshold = (int) (loadFactor * newLength);
table = newTable;
}
public void putAll(Map<? extends K, ? extends V> map) {
int size = map.size();
if (size == 0)
return;
if (size > threshold) {
if (size > MAXIMUM_CAPACITY)
size = MAXIMUM_CAPACITY;
int length = table.length;
while (length < size) length <<= 1;
resize(length);
}
for (Map.Entry<? extends K, ? extends V> e : map.entrySet())
put(e.getKey(), e.getValue());
}
public V remove(Object key) {
key = maskNull(key);
Entry<K, V>[] table = this.table;
int length = table.length;
int hash = hash(key);
int start = index(hash, length);
for (int index = start; ;) {
Entry<K, V> e = table[index];
if (e == null)
return null;
if (e.hash == hash && eq(key, e.key)) {
table[index] = null;
relocate(index);
modCount++;
size--;
return e.value;
}
index = nextIndex(index, length);
if (index == start)
return null;
}
}
private void relocate(int start) {
Entry<K, V>[] table = this.table;
int length = table.length;
int current = nextIndex(start, length);
for (; ;) {
Entry<K, V> e = table[current];
if (e == null)
return;
// A Doug Lea variant of Knuth's Section 6.4 Algorithm R.
// This provides a non-recursive method of relocating
// entries to their optimal positions once a gap is created.
int prefer = index(e.hash, length);
if ((current < prefer && (prefer <= start || start <= current))
|| (prefer <= start && start <= current)) {
table[start] = e;
table[current] = null;
start = current;
}
current = nextIndex(current, length);
}
}
public void clear() {
modCount++;
Entry<K, V>[] table = this.table;
for (int i = 0; i < table.length; i++)
table[i] = null;
size = 0;
}
@SuppressWarnings("unchecked")
public FastCopyHashMap<K, V> clone() {
try {
FastCopyHashMap<K, V> clone = (FastCopyHashMap<K, V>) super.clone();
clone.table = table.clone();
clone.entrySet = null;
clone.values = null;
clone.keySet = null;
return clone;
}
catch (CloneNotSupportedException e) {
// should never happen
throw new IllegalStateException(e);
}
}
public void printDebugStats() {
int optimal = 0;
int total = 0;
int totalSkew = 0;
int maxSkew = 0;
for (int i = 0; i < table.length; i++) {
Entry<K, V> e = table[i];
if (e != null) {
total++;
int target = index(e.hash, table.length);
if (i == target)
optimal++;
else {
int skew = Math.abs(i - target);
if (skew > maxSkew) maxSkew = skew;
totalSkew += skew;
}
}
}
System.out.println(" Size: " + size);
System.out.println(" Real Size: " + total);
System.out.println(" Optimal: " + optimal + " (" + (float) optimal * 100 / total + "%)");
System.out.println(" Average Distnce: " + ((float) totalSkew / (total - optimal)));
System.out.println(" Max Distance: " + maxSkew);
}
public Set<Map.Entry<K, V>> entrySet() {
if (entrySet == null)
entrySet = new EntrySet();
return entrySet;
}
public Set<K> keySet() {
if (keySet == null)
keySet = new KeySet();
return keySet;
}
public Collection<V> values() {
if (values == null)
values = new Values();
return values;
}
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s) throws IOException, ClassNotFoundException {
s.defaultReadObject();
int size = s.readInt();
init(size, loadFactor);
for (int i = 0; i < size; i++) {
K key = (K) s.readObject();
V value = (V) s.readObject();
putForCreate(key, value);
}
this.size = size;
}
@SuppressWarnings("unchecked")
private void putForCreate(K key, V value) {
key = maskNull(key);
Entry<K, V>[] table = this.table;
int hash = hash(key);
int length = table.length;
int index = index(hash, length);
Entry<K, V> e = table[index];
while (e != null) {
index = nextIndex(index, length);
e = table[index];
}
table[index] = new Entry<K, V>(key, hash, value);
}
private void writeObject(java.io.ObjectOutputStream s) throws IOException {
s.defaultWriteObject();
s.writeInt(size);
for (Entry<K, V> e : table) {
if (e != null) {
s.writeObject(unmaskNull(e.key));
s.writeObject(e.value);
}
}
}
private static final class Entry<K, V> {
final K key;
final int hash;
final V value;
Entry(K key, int hash, V value) {
this.key = key;
this.hash = hash;
this.value = value;
}
}
private abstract class FasyCopyHashMapIterator<E> implements Iterator<E> {
private int next = 0;
private int expectedCount = modCount;
private int current = -1;
private boolean hasNext;
Entry<K, V>[] table = FastCopyHashMap.this.table;
public boolean hasNext() {
if (hasNext == true)
return true;
Entry<K, V>[] table = this.table;
for (int i = next; i < table.length; i++) {
if (table[i] != null) {
next = i;
return hasNext = true;
}
}
next = table.length;
return false;
}
protected Entry<K, V> nextEntry() {
if (modCount != expectedCount)
throw new ConcurrentModificationException();
if (!hasNext && !hasNext())
throw new NoSuchElementException();
current = next++;
hasNext = false;
return table[current];
}
@SuppressWarnings("unchecked")
public void remove() {
if (modCount != expectedCount)
throw new ConcurrentModificationException();
int current = this.current;
int delete = current;
if (current == -1)
throw new IllegalStateException();
// Invalidate current (prevents multiple remove)
this.current = -1;
// Start were we relocate
next = delete;
Entry<K, V>[] table = this.table;
if (table != FastCopyHashMap.this.table) {
FastCopyHashMap.this.remove(table[delete].key);
table[delete] = null;
expectedCount = modCount;
return;
}
int length = table.length;
int i = delete;
table[delete] = null;
size--;
for (; ;) {
i = nextIndex(i, length);
Entry<K, V> e = table[i];
if (e == null)
break;
int prefer = index(e.hash, length);
if ((i < prefer && (prefer <= delete || delete <= i))
|| (prefer <= delete && delete <= i)) {
// Snapshot the unseen portion of the table if we have
// to relocate an entry that was already seen by this iterator
if (i < current && current <= delete && table == FastCopyHashMap.this.table) {
int remaining = length - current;
Entry<K, V>[] newTable = (Entry<K, V>[]) new Entry[remaining];
System.arraycopy(table, current, newTable, 0, remaining);
// Replace iterator's table.
// Leave table local var pointing to the real table
this.table = newTable;
next = 0;
}
// Do the swap on the real table
table[delete] = e;
table[i] = null;
delete = i;
}
}
}
}
private class KeyIterator extends FasyCopyHashMapIterator<K> {
public K next() {
return unmaskNull(nextEntry().key);
}
}
private class ValueIterator extends FasyCopyHashMapIterator<V> {
public V next() {
return nextEntry().value;
}
}
private class EntryIterator extends FasyCopyHashMapIterator<Map.Entry<K, V>> {
private class WriteThroughEntry extends SimpleEntry<K, V> {
WriteThroughEntry(K key, V value) {
super(key, value);
}
public V setValue(V value) {
if (table != FastCopyHashMap.this.table)
FastCopyHashMap.this.put(getKey(), value);
return super.setValue(value);
}
}
public Map.Entry<K, V> next() {
Entry<K, V> e = nextEntry();
return new WriteThroughEntry(unmaskNull(e.key), e.value);
}
}
private class KeySet extends AbstractSet<K> {
public Iterator<K> iterator() {
return new KeyIterator();
}
public void clear() {
FastCopyHashMap.this.clear();
}
public boolean contains(Object o) {
return containsKey(o);
}
public boolean remove(Object o) {
int size = size();
FastCopyHashMap.this.remove(o);
return size() < size;
}
public int size() {
return FastCopyHashMap.this.size();
}
}
private class Values extends AbstractCollection<V> {
public Iterator<V> iterator() {
return new ValueIterator();
}
public void clear() {
FastCopyHashMap.this.clear();
}
public int size() {
return FastCopyHashMap.this.size();
}
}
private class EntrySet extends AbstractSet<Map.Entry<K, V>> {
public Iterator<Map.Entry<K, V>> iterator() {
return new EntryIterator();
}
public boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry<?, ?> entry = (Map.Entry<?, ?>) o;
Object value = get(entry.getKey());
return eq(entry.getValue(), value);
}
public void clear() {
FastCopyHashMap.this.clear();
}
public boolean isEmpty() {
return FastCopyHashMap.this.isEmpty();
}
public int size() {
return FastCopyHashMap.this.size();
}
}
protected static class SimpleEntry<K, V> implements Map.Entry<K, V> {
private K key;
private V value;
SimpleEntry(K key, V value) {
this.key = key;
this.value = value;
}
SimpleEntry(Map.Entry<K, V> entry) {
this.key = entry.getKey();
this.value = entry.getValue();
}
public K getKey() {
return key;
}
public V getValue() {
return value;
}
public V setValue(V value) {
V old = this.value;
this.value = value;
return old;
}
public boolean equals(Object o) {
if (this == o)
return true;
if (!(o instanceof Map.Entry))
return false;
Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
return eq(key, e.getKey()) && eq(value, e.getValue());
}
public int hashCode() {
return (key == null ? 0 : hash(key)) ^
(value == null ? 0 : hash(value));
}
public String toString() {
return getKey() + "=" + getValue();
}
}
}