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'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.rapiddweller.common;

import java.util.Collection;
import java.util.Iterator;
import java.util.Set;

/**
 * {@link Set} implementation that tracks the order in which elements where added
 * and returns them in that order by the iterator() method.
 * This is useful for all cases in which elements need to be unique
 * but processed in the original order.
 * Created at 28.02.2009 12:26:35
 *
 * @param  the type of the collection's elements
 * @author Volker Bergmann
 * @since 0.4.8
 */
public class OrderedSet implements Set {

  private final OrderedMap map;

  /**
   * Instantiates a new Ordered set.
   */
  public OrderedSet() {
    map = new OrderedMap<>();
  }

  /**
   * Instantiates a new Ordered set.
   *
   * @param initialCapacity the initial capacity
   */
  public OrderedSet(int initialCapacity) {
    map = new OrderedMap<>(initialCapacity);
  }

  /**
   * Instantiates a new Ordered set.
   *
   * @param initialCapacity the initial capacity
   * @param loadFactor      the load factor
   */
  public OrderedSet(int initialCapacity, float loadFactor) {
    map = new OrderedMap<>(initialCapacity, loadFactor);
  }

  /**
   * Instantiates a new Ordered set.
   *
   * @param source the source
   */
  public OrderedSet(Collection source) {
    map = new OrderedMap<>(source.size());
    addAll(source);
  }

  // Set interface implementation ------------------------------------------------------------------------------------

  @Override
  public boolean add(E item) {
    return (map.put(item, item) == null);
  }

  @Override
  public boolean addAll(Collection source) {
    boolean changed = false;
    for (E item : source) {
      changed |= add(item);
    }
    return changed;
  }

  @Override
  public void clear() {
    map.clear();
  }

  @Override
  public boolean contains(Object item) {
    return map.containsKey(item);
  }

  @Override
  public boolean containsAll(Collection items) {
    for (Object o : items) {
      if (!map.containsKey(o)) {
        return false;
      }
    }
    return true;
  }

  @Override
  public boolean isEmpty() {
    return map.isEmpty();
  }

  @Override
  public Iterator iterator() {
    return map.keySet().iterator();
  }

  @Override
  public boolean remove(Object item) {
    return (map.remove(item) != null);
  }

  @Override
  public boolean removeAll(Collection items) {
    boolean changed = false;
    for (Object item : items) {
      changed |= remove(item);
    }
    return changed;
  }

  @Override
  public boolean retainAll(Collection items) {
    boolean changed = false;
    for (E item : map.keySet()) {
      if (!items.contains(item)) {
        map.remove(item);
        changed = true;
      }
    }
    return changed;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override
  public Object[] toArray() {
    return map.keySet().toArray();
  }

  @Override
  public  T[] toArray(T[] array) {
    return map.keySet().toArray(array);
  }

  // List interface --------------------------------------------------------------------------------------------------

  /**
   * Get e.
   *
   * @param index the index
   * @return the e
   */
  public E get(int index) {
    return map.valueAt(index);
  }

  // java.lang.Object overrides --------------------------------------------------------------------------------------

  @Override
  public int hashCode() {
    return map.hashCode();
  }

  @SuppressWarnings("rawtypes")
  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null || getClass() != obj.getClass()) {
      return false;
    }
    return (this.map.equals(((OrderedSet) obj).map));
  }

  @Override
  public String toString() {
    return map.toString();
  }
}