[jbosscache-commits] JBoss Cache SVN: r6412 - core/trunk/src/main/java/org/jboss/cache/util.
jbosscache-commits at lists.jboss.org
jbosscache-commits at lists.jboss.org
Mon Jul 28 00:11:38 EDT 2008
Author: jason.greene at jboss.com
Date: 2008-07-28 00:11:38 -0400 (Mon, 28 Jul 2008)
New Revision: 6412
Added:
core/trunk/src/main/java/org/jboss/cache/util/FastCopyHashMap.java
Log:
Add initial version of a HashMap that is optimized for copies
Added: core/trunk/src/main/java/org/jboss/cache/util/FastCopyHashMap.java
===================================================================
--- core/trunk/src/main/java/org/jboss/cache/util/FastCopyHashMap.java (rev 0)
+++ core/trunk/src/main/java/org/jboss/cache/util/FastCopyHashMap.java 2008-07-28 04:11:38 UTC (rev 6412)
@@ -0,0 +1,788 @@
+/*
+* JBoss, Home of Professional Open Source
+* Copyright 2005, JBoss Inc., and individual contributors as indicated
+* by the @authors tag. See the copyright.txt 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.cache.util;
+
+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;
+
+/**
+ * A HashMap that is optimized for fast shallow copies.
+ *
+ * @author Jason T. Greene
+ */
+public class FastCopyHashMap<K, V> extends AbstractMap<K, V> implements Map<K, V>, Cloneable, Serializable
+{
+ private static final long serialVersionUID = 10929568968762L;
+
+ /** Same default as HashMap, must be a power of 2 */
+ private static final int DEFAULT_CAPACITY = 16;
+
+ /** 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 detech 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 new IllegalArgumentException("Can not have a negative size table!");
+
+ if (initialCapacity > MAXIMUM_CAPACITY)
+ initialCapacity = MAXIMUM_CAPACITY;
+
+ if (! (loadFactor > 0F && loadFactor <= 1F))
+ throw new IllegalArgumentException("Load factor must be greater than 0 and less than or equal to 1");
+
+ this.loadFactor = loadFactor;
+ init(initialCapacity, loadFactor);
+ }
+
+ private void init(int initialCapacity, float loadFactor)
+ {
+ int c = 1;
+ for (; c < initialCapacity; c <<= 1);
+
+ @SuppressWarnings("unchecked")
+ Entry<K,V>[] table = (Entry<K,V>[]) new Entry[c];
+ this.table = table;
+
+ threshold = (int)(c * loadFactor);
+ }
+
+ public FastCopyHashMap(int initialCapacity)
+ {
+ this(initialCapacity, DEFAULT_LOAD_FACTOR);
+ }
+
+ public FastCopyHashMap()
+ {
+ this(DEFAULT_CAPACITY);
+ }
+
+ // The normal bit spreader...
+ private static final int hash(Object key)
+ {
+ int h = key.hashCode();
+ h ^= (h >>> 20) ^ (h >>> 12);
+ return h ^ (h >>> 7) ^ (h >>> 4);
+ }
+
+ private int nextIndex(int index, int length)
+ {
+ index = (index >= length - 1) ? 0 : index + 1;
+ return index;
+ }
+
+ private static final boolean eq(Object o1, Object o2)
+ {
+ return o1 == o2 || (o1 != null && o1.equals(o2));
+ }
+
+ private static final 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)
+ {
+ if (key == null)
+ throw new IllegalArgumentException("Null keys are not allowed");
+
+ int hash = hash(key);
+ int length = table.length;
+ int index = index(hash, length);
+
+ for (;;)
+ {
+ 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);
+ }
+ }
+
+ public boolean containsKey(Object key)
+ {
+ if (key == null)
+ throw new IllegalArgumentException("Null keys are not allowed");
+
+ int hash = hash(key);
+ int length = table.length;
+ int index = index(hash, length);
+
+ for (;;)
+ {
+ 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);
+ }
+ }
+
+ 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)
+ {
+ if (key == null)
+ throw new IllegalArgumentException("Null keys are not allowed");
+
+
+ Entry<K, V>[] table = this.table;
+ int hash = hash(key);
+ int length = table.length;
+ int start = index(hash, length);
+ int index = start;
+
+
+ for (;;)
+ {
+ 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 new IllegalStateException("Table is full!");
+ }
+
+ modCount++;
+ table[index] = new Entry<K, V>(key, hash, value);
+ if (++size >= threshold)
+ resize(length);
+
+ return null;
+ }
+
+
+ private void resize(int from)
+ {
+ int newLength = from << 1;
+
+ // Can't get any bigger
+ if (newLength > MAXIMUM_CAPACITY || newLength <= from)
+ return;
+
+ @SuppressWarnings("unchecked")
+ 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;
+ for (; 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)
+ {
+ if (key == null)
+ throw new IllegalArgumentException("Null keys are not allowed");
+
+ 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;
+ }
+
+ public Object clone()
+ {
+ try
+ {
+ @SuppressWarnings("unchecked")
+ 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);
+ }
+ }
+
+ private void putForCreate(K key, V value)
+ {
+ if (key == null)
+ throw new IllegalArgumentException("Null keys are not allowed");
+
+ 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 e : table)
+ {
+ if (e != null)
+ {
+ s.writeObject(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];
+ }
+
+ 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;
+ @SuppressWarnings("unchecked")
+ 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 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(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 hash(key) ^
+ (value == null ? 0 : hash(value));
+ }
+
+ public String toString()
+ {
+ return getKey() + "=" + getValue();
+ }
+ }
+}
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