com.jogamp.common.util.ArrayHashMap Maven / Gradle / Ivy
/**
* Copyright 2015 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of JogAmp Community.
*/
package com.jogamp.common.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* {@link HashMap} implementation backed by an {@link ArrayList} to preserve order of values.
*
* Implementation properties are:
*
* - Unique elements utilizing {@link java.lang.Object#hashCode()} for O(1) operations, see below.
* - Java 1.5 compatible
*
*
* O(1) operations:
*
* - put new key-value-pair(s)
* - test for containment
* - trying to remove non existent elements
*
*
* O(n) operations:
*
* - put existing key-value-pair(s)
* - removing existing elements
*
*
* For thread safety, the application shall decorate access to instances via
* {@link com.jogamp.common.util.locks.RecursiveLock}.
*
*/
public class ArrayHashMap
implements Cloneable, Map
{
/**
* Default load factor: {@value}
*/
public static final float DEFAULT_LOAD_FACTOR = 0.75f;
/**
* The default initial capacity: {@value}
*/
public static final int DEFAULT_INITIAL_CAPACITY = 16;
private final HashMap map; // key -> object
private final ArrayList data; // list of objects
private final boolean supportNullValue;
/**
*
* @param supportNullValue Use {@code true} for default behavior, i.e. {@code null} can be a valid value.
* Use {@code false} if {@code null} is not a valid value,
* here {@link #put(Object, Object)} and {@link #remove(Object)} will be optimized.
* @param initialCapacity use {@link #DEFAULT_INITIAL_CAPACITY} for default
* @param loadFactor use {@link #DEFAULT_LOAD_FACTOR} for default
* @see #supportsNullValue()
*/
public ArrayHashMap(final boolean supportNullValue, final int initialCapacity, final float loadFactor) {
this.map = new HashMap(initialCapacity, loadFactor);
this.data = new ArrayList(initialCapacity);
this.supportNullValue = supportNullValue;
}
/**
* @return a shallow copy of this ArrayHashMap, elements are not copied.
*/
public ArrayHashMap(final ArrayHashMap o) {
map = new HashMap(o.map);
data = new ArrayList(o.data);
supportNullValue = o.supportNullValue;
}
/**
* Returns {@code true} for default behavior, i.e. {@code null} can be a valid value.
*
* Returns {@code false} if {@code null} is not a valid value,
* here {@link #put(Object, Object)} and {@link #remove(Object)} are optimized operations.
*
* @see #ArrayHashMap(boolean, int, float)
*/
public final boolean supportsNullValue() { return supportNullValue; }
//
// Cloneable
//
/**
* Implementation uses {@link #ArrayHashMap(ArrayHashMap)}.
* @return a shallow copy of this ArrayHashMap, elements are not copied.
*/
@Override
public final Object clone() {
return new ArrayHashMap(this);
}
/**
* Returns this object ordered ArrayList. Use w/ care, it's not a copy.
* @see #toArrayList()
*/
public final ArrayList getData() { return data; }
/**
* @return a shallow copy of this ArrayHashMap's ArrayList, elements are not copied.
* @see #getData()
*/
public final ArrayList toArrayList() {
return new ArrayList(data);
}
/** Returns this object hash map. Use w/ care, it's not a copy. */
public final HashMap getMap() { return map; }
@Override
public final String toString() { return data.toString(); }
//
// Map
//
@Override
public final void clear() {
data.clear();
map.clear();
}
@Override
public Set keySet() {
return map.keySet();
}
/**
* {@inheritDoc}
*
* See {@link #getData()} and {@link #toArrayList()}.
*
* @see #getData()
* @see #toArrayList()
*/
@Override
public Collection values() {
return map.values();
}
@Override
public Set> entrySet() {
return map.entrySet();
}
@Override
public final V get(final Object key) {
return map.get(key);
}
/**
* {@inheritDoc}
*
* This is an O(1) operation, in case the key does not exist,
* otherwise O(n).
*
* @throws NullPointerException if {@code value} is {@code null} but {@link #supportsNullValue()} == {@code false}
*/
@Override
public final V put(final K key, final V value) throws NullPointerException {
final V oldValue;
if( supportNullValue ) {
// slow path
final boolean exists = map.containsKey(key);
if(!exists) {
// !exists
if( null != ( oldValue = map.put(key, value) ) ) {
// slips a valid null ..
throw new InternalError("Already existing, but checked before: "+key+" -> "+oldValue);
}
} else {
// exists
oldValue = map.put(key, value);
if( !data.remove(oldValue) ) {
throw new InternalError("Already existing, but not in list: "+oldValue);
}
}
} else {
checkNullValue(value);
// fast path
if( null != ( oldValue = map.put(key, value) ) ) {
// exists
if( !data.remove(oldValue) ) {
throw new InternalError("Already existing, but not in list: "+oldValue);
}
}
}
if(!data.add(value)) {
throw new InternalError("Couldn't add value to list: "+value);
}
return oldValue;
}
@Override
public void putAll(final Map m) {
for (final Iterator> i = m.entrySet().iterator(); i.hasNext(); ) {
final Map.Entry e = i.next();
put(e.getKey(), e.getValue());
}
}
/**
* {@inheritDoc}
*
* This is an O(1) operation, in case the key does not exist,
* otherwise O(n).
*
*/
@Override
public final V remove(final Object key) {
if( supportNullValue ) {
if( map.containsKey(key) ) {
// exists
final V oldValue = map.remove(key);
if ( !data.remove(oldValue) ) {
throw new InternalError("Couldn't remove prev mapped pair: "+key+" -> "+oldValue);
}
return oldValue;
}
} else {
final V oldValue;
if ( null != (oldValue = map.remove(key) ) ) {
// exists
if ( !data.remove(oldValue) ) {
throw new InternalError("Couldn't remove prev mapped pair: "+key+" -> "+oldValue);
}
}
return oldValue;
}
return null;
}
@Override
public final boolean containsKey(final Object key) {
return map.containsKey(key);
}
@Override
public boolean containsValue(final Object value) {
return map.containsValue(value);
}
@Override
public final boolean equals(final Object arrayHashMap) {
if ( !(arrayHashMap instanceof ArrayHashMap) ) {
return false;
}
return map.equals(((ArrayHashMap)arrayHashMap).map);
}
@Override
public final int hashCode() {
return map.hashCode();
}
@Override
public final boolean isEmpty() {
return data.isEmpty();
}
@Override
public final int size() {
return data.size();
}
private static final void checkNullValue(final Object value) throws NullPointerException {
if( null == value ) {
throw new NullPointerException("Null value not supported");
}
}
}