335 lines
8.6 KiB
Java
335 lines
8.6 KiB
Java
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package com.jwetherell.algorithms.data_structures;
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import com.jwetherell.algorithms.data_structures.SkipList.Node;
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import com.jwetherell.algorithms.data_structures.interfaces.IMap;
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/**
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* A set used to store key->values pairs, this is an implementation of an
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* associative array.
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*
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* This implementation is a composition of a Skip List as the backing structure.
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*
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* http://en.wikipedia.org/wiki/Skip_list
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* http://en.wikipedia.org/wiki/Associative_array
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*
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* @author Justin Wetherell <phishman3579@gmail.com>
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*/
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@SuppressWarnings("unchecked")
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public class SkipListMap<K extends Comparable<K>, V> implements SkipList.INodeCreator<K>, IMap<K,V> {
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private SkipList<K> list = null;
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public SkipListMap() {
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list = new SkipList<K>(this);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public V put(K key, V value) {
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V prev = null;
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SkipList.Node<K> node = list.addValue(key);
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if (node instanceof SkipListMapNode) {
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SkipListMapNode<K, V> treeMapNode = (SkipListMapNode<K, V>) node;
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if (treeMapNode.value!=null) prev = treeMapNode.value;
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treeMapNode.value = value;
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}
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return prev;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public V get(K key) {
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SkipList.Node<K> node = list.getNode(key);
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if (node instanceof SkipListMapNode) {
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SkipListMapNode<K, V> mapNode = (SkipListMapNode<K, V>) node;
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return mapNode.value;
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}
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return null;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public boolean contains(K key) {
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return list.contains(key);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public V remove(K key) {
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Node<K> node = list.removeValue(key);
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V value = null;
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if (node instanceof SkipListMapNode) {
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SkipListMapNode<K, V> treeMapNode = (SkipListMapNode<K, V>) node;
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value = treeMapNode.value;
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treeMapNode.data = null;
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treeMapNode.value = null;
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}
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return value;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public void clear() {
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list.clear();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public int size() {
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return list.size();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public boolean validate() {
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if (list==null) return true;
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java.util.Set<K> keys = new java.util.HashSet<K>();
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Node<K> node = list.head;
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if (node==null) return true;
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if (!validate(node,keys)) return false;
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Node<K> next = node.getNext(0);
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while (next!=null) {
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if (!validate(next, keys)) return false;
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next = next.getNext(0);
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}
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return (keys.size()==size());
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}
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private boolean validate(Node<K> node, java.util.Set<K> keys) {
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if (!(node instanceof SkipListMapNode)) return false;
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SkipListMapNode<K,V> tmn = (SkipListMapNode<K,V>)node;
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K k = tmn.data;
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V v = tmn.value;
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if (k==null || v==null) return false;
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if (keys.contains(k)) return false;
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keys.add(k);
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public java.util.Map<K,V> toMap() {
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return (new JavaCompatibleTreeMap<K,V>(this));
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public String toString() {
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StringBuilder builder = new StringBuilder();
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if (list!=null && list.head!=null) {
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Node<K> node = list.head;
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while (node!=null) {
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if (!(node instanceof SkipListMapNode)) continue;
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SkipListMapNode<K,V> sln = (SkipListMapNode<K, V>) node;
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builder.append(sln.data).append("=").append(sln.value);
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node = node.getNext(0);
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if (node!=null) builder.append("\n");
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}
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}
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return builder.toString();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public SkipList.Node<K> createNewNode(int level, K key) {
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return (new SkipListMapNode<K, V>(level, key));
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public void swapNode(Node<K> node, Node<K> next) {
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K key = node.data;
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node.data = next.data;
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next.data = key;
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if (node instanceof SkipListMapNode && next instanceof SkipListMapNode) {
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SkipListMapNode<K,V> node2 = (SkipListMapNode<K,V>) node;
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SkipListMapNode<K,V> next2 = (SkipListMapNode<K,V>) next;
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V value = node2.value;
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node2.value = next2.value;
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next2.value = value;
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}
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}
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protected static class SkipListMapNode<K extends Comparable<K>, V> extends SkipList.Node<K> {
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protected V value = null;
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protected SkipListMapNode(int level, K key) {
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super(level, key);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public String toString() {
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StringBuilder builder = new StringBuilder();
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builder.append(super.toString());
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builder.append("value = ").append(value).append("\n");
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return builder.toString();
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}
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}
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private static class JavaCompatibleIteratorWrapper<K extends Comparable<K>,V> implements java.util.Iterator<java.util.Map.Entry<K, V>> {
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private SkipListMap<K,V> map = null;
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private java.util.Iterator<java.util.Map.Entry<K, V>> iter = null;
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private java.util.Map.Entry<K, V> lastEntry = null;
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public JavaCompatibleIteratorWrapper(SkipListMap<K,V> map, java.util.Iterator<java.util.Map.Entry<K, V>> iter) {
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this.map = map;
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this.iter = iter;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public boolean hasNext() {
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if (iter==null) return false;
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return iter.hasNext();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public java.util.Map.Entry<K, V> next() {
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if (iter==null) return null;
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lastEntry = iter.next();
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return lastEntry;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public void remove() {
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if (iter==null || lastEntry==null) return;
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map.remove(lastEntry.getKey());
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iter.remove();
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}
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}
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private static class JavaCompatibleMapEntry<K extends Comparable<K>,V> extends java.util.AbstractMap.SimpleEntry<K,V> {
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private static final long serialVersionUID = 3282082818647198608L;
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public JavaCompatibleMapEntry(K key, V value) {
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super(key, value);
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}
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}
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private static class JavaCompatibleTreeMap<K extends Comparable<K>,V> extends java.util.AbstractMap<K,V> {
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private SkipListMap<K,V> map = null;
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protected JavaCompatibleTreeMap(SkipListMap<K,V> map) {
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this.map = map;
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public V put(K key, V value) {
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return map.put(key, value);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public V remove(Object key) {
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return map.remove((K)key);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public void clear() {
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map.clear();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public boolean containsKey(Object key) {
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return map.contains((K)key);
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public int size() {
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return map.size();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public java.util.Set<java.util.Map.Entry<K, V>> entrySet() {
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java.util.Set<java.util.Map.Entry<K, V>> set = new java.util.HashSet<java.util.Map.Entry<K, V>>() {
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private static final long serialVersionUID = 1L;
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/**
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* {@inheritDoc}
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*/
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@Override
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public java.util.Iterator<java.util.Map.Entry<K, V>> iterator() {
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return (new JavaCompatibleIteratorWrapper<K,V>(map,super.iterator()));
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}
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};
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if (map.list!=null && map.list.head!=null) {
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Node<K> n = map.list.head;
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while (n!=null) {
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if (!(n instanceof SkipListMapNode)) continue;
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SkipListMapNode<K,V> node = (SkipListMapNode<K,V>)n;
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set.add(new JavaCompatibleMapEntry<K,V>(node.data,node.value));
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n = node.getNext(0);
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}
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}
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return set;
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}
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}
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}
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