/*
 *  Copyright 2004 Clinton Begin
 *
 *  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.ibatis.common.util;

import java.util.*;

/**
 * Implementation of PaginatedList backed by an ArrayList
 * @deprecated All paginated list features have been deprecated
 */
public class PaginatedArrayList implements PaginatedList {

  private static final ArrayList EMPTY_LIST = new ArrayList(0);

  private List list;
  private List page;
  private int pageSize;
  private int index;

  /**
   * @param pageSize
   */
  public PaginatedArrayList(int pageSize) {
    this.pageSize = pageSize;
    this.index = 0;
    this.list = new ArrayList();
    repaginate();
  }

  /**
   * Constructor to set the initial size and the page size
   * @param initialCapacity - the initial size
   * @param pageSize - the page size
   */
  public PaginatedArrayList(int initialCapacity, int pageSize) {
    this.pageSize = pageSize;
    this.index = 0;
    this.list = new ArrayList(initialCapacity);
    repaginate();
  }

  /**
   * Constructor to create an instance using an existing collection
   * @param c - the collection to build the instance with
   * @param pageSize - the page size
   */
  public PaginatedArrayList(Collection c, int pageSize) {
    this.pageSize = pageSize;
    this.index = 0;
    this.list = new ArrayList(c);
    repaginate();
  }

  private void repaginate() {
    if (list.isEmpty()) {
      page = EMPTY_LIST;
    } else {
      int start = index * pageSize;
      int end = start + pageSize - 1;
      if (end >= list.size()) {
        end = list.size() - 1;
      }
      if (start >= list.size()) {
        index = 0;
        repaginate();
      } else if (start < 0) {
        index = list.size() / pageSize;
        if (list.size() % pageSize == 0) {
          index--;
        }
        repaginate();
      } else {
        page = list.subList(start, end + 1);
      }
    }
  }

  /* List accessors (uses page) */

  public int size() {
    return page.size();
  }

  public boolean isEmpty() {
    return page.isEmpty();
  }

  public boolean contains(Object o) {
    return page.contains(o);
  }

  public Iterator iterator() {
    return page.iterator();
  }

  public Object[] toArray() {
    return page.toArray();
  }

  public Object[] toArray(Object a[]) {
    return page.toArray(a);
  }

  public boolean containsAll(Collection c) {
    return page.containsAll(c);
  }

  public Object get(int index) {
    return page.get(index);
  }

  public int indexOf(Object o) {
    return page.indexOf(o);
  }

  public int lastIndexOf(Object o) {
    return page.lastIndexOf(o);
  }

  public ListIterator listIterator() {
    return page.listIterator();
  }

  public ListIterator listIterator(int index) {
    return page.listIterator(index);
  }

  public List subList(int fromIndex, int toIndex) {
    return page.subList(fromIndex, toIndex);
  }

  /* List mutators (uses master list) */

  public boolean add(Object o) {
    boolean b = list.add(o);
    repaginate();
    return b;
  }

  public boolean remove(Object o) {
    boolean b = list.remove(o);
    repaginate();
    return b;
  }

  public boolean addAll(Collection c) {
    boolean b = list.addAll(c);
    repaginate();
    return b;
  }

  public boolean addAll(int index, Collection c) {
    boolean b = list.addAll(index, c);
    repaginate();
    return b;
  }

  public boolean removeAll(Collection c) {
    boolean b = list.removeAll(c);
    repaginate();
    return b;
  }

  public boolean retainAll(Collection c) {
    boolean b = list.retainAll(c);
    repaginate();
    return b;
  }

  public void clear() {
    list.clear();
    repaginate();
  }

  public Object set(int index, Object element) {
    Object o = list.set(index, element);
    repaginate();
    return o;
  }

  public void add(int index, Object element) {
    list.add(index, element);
    repaginate();
  }

  public Object remove(int index) {
    Object o = list.remove(index);
    repaginate();
    return o;
  }

  /* Paginated List methods */

  public int getPageSize() {
    return pageSize;
  }

  public boolean isFirstPage() {
    return index == 0;
  }

  public boolean isMiddlePage() {
    return !(isFirstPage() || isLastPage());
  }

  public boolean isLastPage() {
    return list.size() - ((index + 1) * pageSize) < 1;
  }

  public boolean isNextPageAvailable() {
    return !isLastPage();
  }

  public boolean isPreviousPageAvailable() {
    return !isFirstPage();
  }

  public boolean nextPage() {
    if (isNextPageAvailable()) {
      index++;
      repaginate();
      return true;
    } else {
      return false;
    }
  }

  public boolean previousPage() {
    if (isPreviousPageAvailable()) {
      index--;
      repaginate();
      return true;
    } else {
      return false;
    }
  }

  public void gotoPage(int pageNumber) {
    index = pageNumber;
    repaginate();
  }

  public int getPageIndex() {
    return index;
  }

}