浅谈线性表的原理及简单实现方法

package online.jfree.base;

/**
 * author : Guo LiXiao
 * date : 2017-6-14 11:46
 */

public interface LineList {

 /**
  * lineList 是否为空
  * @return
  */
 boolean isEmpty();

 /**
  * 清空 lineList
  */
 void clear();

 /**
  * 获取指定位置元素
  * @param index
  * @return
  */
 E get(int index);

 /**
  * 获取元素第一次出现的位置
  * @param e
  * @return
  */
 int indexOf(E e);

 /**
  * 判断 lineList是否包含指定元素
  * @param e
  * @return
  */
 boolean contains(E e);

 /**
  * 设置指定位置数据，如数据已存在 则覆盖原数据
  * @param index
  * @param e
  * @return
  */
 E set(int index, E e);

 /**
  * 移除指定位置元素
  * @param index
  * @return
  */
 E remove(int index);

 /**
  * 在lineList结尾插入元素
  * @param e
  * @return
  */
 E add(E e);

 /**
  * 在index后面插入元素
  * @param index
  * @param e
  * @return
  */
 E add(int index, E e);

 /**
  * 返回lineList长度
  * @return
  */
 int size();



}

package online.jfree.base;

/**
 * author : Guo LiXiao
 * date : 2017-6-15 13:44
 */

public class OrderedLineList implements LineList {

 private static final int INIT_CAPACITY = 10;

 private transient E[] elementData;

 private transient int elementLength;

 private int size;

 public OrderedLineList() {
  this(0);
 }

 public OrderedLineList(int initCapacity) {
  init(initCapacity);
 }

 private void init(int initCapacity) {
  if (initCapacity >= 0) {
   this.elementData = (E[]) new Object[initCapacity];
   this.elementLength = initCapacity;
  } else {
   throw new IllegalArgumentException("Illegal Capacity: " +
     initCapacity);
  }
  this.size = 0;
 }

 /**
  * 扩容
  */
 private void dilatation() {
  int oldCapacity = this.elementLength;
  int newCapacity = oldCapacity;
  if (oldCapacity <= this.size) {
   newCapacity = oldCapacity + INIT_CAPACITY;
  }else if(oldCapacity - INIT_CAPACITY > this.size){
   newCapacity = oldCapacity - INIT_CAPACITY;
  }
  if (oldCapacity != newCapacity){
   E[] newElementData = (E[]) new Object[newCapacity];
   System.arraycopy(elementData, 0, newElementData, 0, oldCapacity);
   this.elementLength = newCapacity;
   this.elementData = newElementData;
  }
 }

 /**
  * 校验列表索引越界
  * @param index
  */
 private void checkCapacity(int index){
  if (index > this.size - 1 || index < 0)
   throw new IndexOutOfBoundsException(new StringBuffer("[index : ").append(index).append("] , [size : ").append(size).append("] ").toString());
 }

 @Override
 public boolean isEmpty() {
  return this.size == 0;
 }

 @Override
 public void clear() {
  this.init(0);
 }

 @Override
 public E get(int index) {
  this.checkCapacity(index);
  return this.elementData[index];
 }

 @Override
 public int indexOf(E e) {
  for (int i = 0; i < this.size; i++){
   if (e == null && elementData[i] == null || e.equals(elementData[i])){
    return i;
   }
  }
  return -1;
 }

 @Override
 public boolean contains(E e) {
  return this.indexOf(e) > 0;
 }

 @Override
 public E set(int index, E e) {
  this.checkCapacity(index);
  this.dilatation();
  E oldElement = this.elementData[index];
  this.elementData[index] = e;
  return oldElement;
 }

 @Override
 public E remove(int index) {
  this.dilatation();
  E e = elementData[index];
  if (index == size - 1) elementData[index] = null;
  else {
   int length = size - index - 1;
   System.arraycopy(elementData, index + 1, elementData, index, length);
  }
  size --;
  return e;
 }

 @Override
 public E add(E e) {
  return this.add(size, e);
 }

 @Override
 public E add(int index, E e) {
  this.dilatation();
  if (index == size) elementData[index] = e;
  else {
   index++;
   int lastLength = size - index;
   E[] lastElementData = (E[]) new Object[lastLength];
   System.arraycopy(elementData, index, lastElementData, 0, lastLength);
   elementData[index] = e;
   System.arraycopy(lastElementData, 0, elementData, index + 1, lastLength);
  }
  size ++ ;
  return e;
 }

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

}