【笔记】Java ArrayList

存储结构

• transient Object[] elementdata
• DEFAULT_CAPACITY =10

初始化

• 默认构造器初始化

• 带参构造器

  • int initcapacity

  • ArrayList(Collection<? extends E> c)

主要操作

• 添加数据

  • add(E e)
  • add(int index, E e)
  • addAll(Collection<? extends E> c)
  • addAll(int index, Collection<? extends E> c)
  • index 不能大于 size

• 删除数据

  • remove(int index)
  • remove(Obejct obj)
  • removeAll(Collection<? extends E> c), 删除list中与集合C 中相同的元素
  • removeIf(Predicate<? super E> filter) ,通过filter 删掉满足条件的元素
  • clear()

• 查询数据

  • get(int index) ,根据索引进行查询
  • contains(Object obj) ,查询是否存在相关对象
  • indexOf(Objext o)

• 修改数据

  • set(int index, Object obj),
  • replaceAll(UnaryOperator operator)

• 排序

  • sort(Comparator<? extends super E> c)

• 扩容

  private void grow(int minCapacity) {
      // overflow-conscious code
      int oldCapacity = elementData.length;
      int newCapacity = oldCapacity + (oldCapacity >> 1);
      if (newCapacity - minCapacity < 0)
          newCapacity = minCapacity;
      if (newCapacity - MAX_ARRAY_SIZE > 0)
          newCapacity = hugeCapacity(minCapacity);
      // minCapacity is usually close to size, so this is a win:
      elementData = Arrays.copyOf(elementData, newCapacity);
  }
  

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来源： https://www.cnblogs.com/KiritoUzumaki/p/15169164.html