org.javimmutable.collections.inorder.JImmutableInsertOrderMap Maven / Gradle / Ivy
Show all versions of javimmutable-collections Show documentation
///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2017, Burton Computer Corporation
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 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.
//
// Neither the name of the Burton Computer Corporation nor the names
// of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 THE COPYRIGHT
// HOLDER 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.
package org.javimmutable.collections.inorder;
import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.JImmutableMap;
import org.javimmutable.collections.MapEntry;
import org.javimmutable.collections.SplitableIterator;
import org.javimmutable.collections.array.trie32.TrieArray;
import org.javimmutable.collections.common.AbstractJImmutableMap;
import org.javimmutable.collections.cursors.TransformCursor;
import org.javimmutable.collections.hash.JImmutableHashMap;
import org.javimmutable.collections.iterators.TransformIterator;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import static org.javimmutable.collections.common.StreamConstants.SPLITERATOR_ORDERED;
/**
* JImmutableMap implementation that allows iteration over members in the order in which they
* were inserted into the map. Maintains two parallel data structures, one for sorting and
* the other for storing entries. Gets are approximately as fast as hash map gets but updates
* are significantly slower. Iteration is comparable to sorted map iteration.
*
* Use a hash or tree map whenever possible but this class performs well enough for most cases
* where insertion order is important to an algorithm.
*/
@Immutable
public class JImmutableInsertOrderMap
extends AbstractJImmutableMap
{
@SuppressWarnings("unchecked")
public static final JImmutableInsertOrderMap EMPTY = new JImmutableInsertOrderMap(TrieArray.of(), JImmutableHashMap.of(), 0);
private final TrieArray> sortedNodes;
private final JImmutableMap> hashedNodes;
private final int nextIndex;
private JImmutableInsertOrderMap(TrieArray> sortedNodes,
JImmutableMap> hashedNodes,
int nextIndex)
{
assert sortedNodes.size() == hashedNodes.size();
this.sortedNodes = sortedNodes;
this.hashedNodes = hashedNodes;
this.nextIndex = nextIndex;
}
@SuppressWarnings("unchecked")
public static JImmutableInsertOrderMap of()
{
return (JImmutableInsertOrderMap)EMPTY;
}
@Override
public V getValueOr(K key,
V defaultValue)
{
final Node current = hashedNodes.get(key);
return (current != null) ? current.getValue() : defaultValue;
}
@Nonnull
@Override
public Holder find(@Nonnull K key)
{
final Node current = hashedNodes.get(key);
return (current != null) ? current : Holders.of();
}
@Nonnull
@Override
public Holder> findEntry(@Nonnull K key)
{
final Node current = hashedNodes.get(key);
return (current != null) ? Holders.of(current) : Holders.of();
}
@Nonnull
@Override
public JImmutableInsertOrderMap assign(@Nonnull K key,
V value)
{
final Node current = hashedNodes.get(key);
if (current == null) {
final Node newNode = new Node<>(key, value, nextIndex);
return new JImmutableInsertOrderMap<>(sortedNodes.assign(newNode.index, newNode),
hashedNodes.assign(key, newNode),
nextIndex + 1);
} else if (current.getValue() == value) {
return this;
} else {
final Node newNode = current.withValue(value);
return new JImmutableInsertOrderMap<>(sortedNodes.assign(newNode.index, newNode),
hashedNodes.assign(key, newNode),
nextIndex);
}
}
@Nonnull
@Override
public JImmutableInsertOrderMap delete(@Nonnull K key)
{
final Node current = hashedNodes.get(key);
if (current != null) {
return new JImmutableInsertOrderMap<>(sortedNodes.delete(current.index),
hashedNodes.delete(key),
nextIndex);
} else {
return this;
}
}
@Override
public int size()
{
return hashedNodes.size();
}
@Nonnull
@Override
public JImmutableInsertOrderMap deleteAll()
{
return of();
}
@Override
@Nonnull
public Cursor> cursor()
{
return TransformCursor.of(sortedNodes.cursor(), e -> e.getValue());
}
@Nonnull
@Override
public SplitableIterator> iterator()
{
return TransformIterator.of(sortedNodes.iterator(), e -> e.getValue());
}
@Override
public int getSpliteratorCharacteristics()
{
return SPLITERATOR_ORDERED;
}
@Override
public void checkInvariants()
{
//TODO: fix empty checkInvariants()
}
/**
* An Entry implementation that also stores the sortedKeys index corresponding to this node's key.
*/
@Immutable
private static class Node
extends MapEntry
implements Holder
{
private final int index;
private Node(K key,
V value,
int index)
{
super(key, value);
this.index = index;
}
@Override
public boolean isEmpty()
{
return false;
}
@Override
public boolean isFilled()
{
return true;
}
@Override
public V getValueOrNull()
{
return value;
}
@Override
public V getValueOr(V defaultValue)
{
return value;
}
private Node withValue(V value)
{
return new Node<>(key, value, index);
}
}
}