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Library providing immutable/persistent collection classes for
Java. While collections are immutable they provide methods for
adding and removing values by creating new modified copies of
themselves. Each copy shares almost all of its structure with
other copies to minimize memory consumption.
///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2013, Burton Computer Corporation
// All rights reserved.
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//
// 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
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// of its contributors may be used to endorse or promote products
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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package org.javimmutable.collections.tree;
import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.Insertable;
import org.javimmutable.collections.common.AbstractJImmutableMap;
import org.javimmutable.collections.common.IteratorAdaptor;
import org.javimmutable.collections.common.MapAdaptor;
import org.javimmutable.collections.cursors.StandardCursor;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
public class JImmutableTreeMap
extends AbstractJImmutableMap
{
@SuppressWarnings("unchecked")
private static final JImmutableTreeMap EMPTY = new JImmutableTreeMap(new ComparableComparator());
private final Comparator comparator;
private final TreeNode root;
private final int size;
/**
* Constructs an empty map using the specified Comparator. Note that the Comparator MUST BE IMMUTABLE.
* The Comparator will be retained and used throughout the life of the map and its offspring and will
* be aggressively shared so it is imperative that the Comparator be completely immutable.
*
* @param comparator
*/
public JImmutableTreeMap(Comparator comparator)
{
this(comparator, null, 0);
}
@SuppressWarnings("unchecked")
public static , V> JImmutableTreeMap of()
{
return (JImmutableTreeMap)EMPTY;
}
/**
* Constructs an empty map using the specified Comparator. Note that the Comparator MUST BE IMMUTABLE.
* The Comparator will be retained and used throughout the life of the map and its offspring and will
* be aggressively shared so it is imperative that the Comparator be completely immutable.
*
* @param comparator
*/
public static JImmutableTreeMap of(Comparator comparator)
{
return new JImmutableTreeMap(comparator);
}
/**
* Constructs a new map containing the same key/value pairs as map using a ComparableComparator
* to compare the keys.
*
* @param map
* @param
* @param
* @return
*/
public static , V> JImmutableTreeMap of(Map map)
{
JImmutableTreeMap answer = of();
for (Map.Entry entry : map.entrySet()) {
answer = answer.assign(entry.getKey(), entry.getValue());
}
return answer;
}
private JImmutableTreeMap(Comparator comparator,
TreeNode root,
int size)
{
this.comparator = comparator;
this.root = root;
this.size = size;
}
@Override
public V get(K key)
{
return find(key).getValueOrNull();
}
@Override
public Holder find(K key)
{
if (key == null) {
throw new NullPointerException();
}
if (root == null) {
return Holders.of();
} else {
return root.find(comparator, key);
}
}
@Override
public Holder> findEntry(K key)
{
if (key == null) {
throw new NullPointerException();
}
if (root == null) {
return Holders.of();
} else {
return root.findEntry(comparator, key);
}
}
@Override
public JImmutableTreeMap assign(K key,
V value)
{
if (key == null) {
throw new NullPointerException();
}
if (root == null) {
return create(new LeafNode(key, value), 1);
} else {
UpdateResult result = root.update(comparator, key, value);
switch (result.type) {
case UNCHANGED:
return this;
case INPLACE:
return create(result.newNode, result.sizeDelta);
case SPLIT:
return create(new TwoNode(result.newNode,
result.extraNode,
result.newNode.getMaxKey(),
result.extraNode.getMaxKey()),
result.sizeDelta);
}
throw new RuntimeException();
}
}
@Override
public JImmutableTreeMap delete(K key)
{
if (key == null) {
throw new NullPointerException();
}
if (root == null) {
return this;
}
DeleteResult result = root.delete(comparator, key);
if (result.type == DeleteResult.Type.UNCHANGED) {
return this;
} else {
return create(result.node, -1);
}
}
@Override
public int size()
{
return size;
}
@Override
public JImmutableTreeMap deleteAll()
{
return of(comparator);
}
@Override
public Map getMap()
{
return MapAdaptor.of(this);
}
/**
* Adds the key/value pair to this map. Any value already existing for the specified key
* is replaced with the new value.
*
* @param e
* @return
*/
@Override
public Insertable> insert(Entry e)
{
return assign(e.getKey(), e.getValue());
}
@Override
public Iterator> iterator()
{
return IteratorAdaptor.of(cursor());
}
@Override
public Cursor> cursor()
{
return (root == null) ? StandardCursor.>of() : root.cursor();
}
public List getKeysList()
{
List keys = new LinkedList();
for (Entry entry : this) {
keys.add(entry.getKey());
}
return Collections.unmodifiableList(keys);
}
public void verifyDepthsMatch()
{
if (root != null) {
root.verifyDepthsMatch();
}
}
public Comparator getComparator()
{
return comparator;
}
private JImmutableTreeMap create(TreeNode root,
int sizeDelta)
{
return new JImmutableTreeMap(comparator, root, size + sizeDelta);
}
}
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