clear() 删除错有缓冲区里的数据
public void clear() {
modCount++;
final Object[] es = elementData;
for (int to = size, i = size = 0; i < to; i++)// 实际存储数据置 0,从 0 到实际存储的位置循环置 null
es[i] = null;
}
addAll(Collection<? extends E> c) 添加集合到当前集合
public boolean addAll(Collection<? extends E> c) {Object[] a = c.toArray();// 转化为数组
modCount++;
int numNew = a.length;// 添加数据长度
if (numNew == 0)
return false;// 长度为 0 直接返回 false
Object[] elementData;
final int s;
if (numNew > (elementData = this.elementData).length - (s = size))// 旧数据长度 + 新数据长度大于缓冲区大小,就扩容
elementData = grow(s + numNew);// 扩大为可以容纳旧数据 + 新数据大小
System.arraycopy(a, 0, elementData, s, numNew);// 新数据从 0 位开始复制到缓冲区的 s 位处,复制长度为新数据长度
size = s + numNew;
return true;
}
addAll(int index, Collection<? extends E> c) 添加集合到当前集合的固定位置
public boolean addAll(int index, Collection<? extends E> c) {rangeCheckForAdd(index);// 确认下标
Object[] a = c.toArray();// 转数组
modCount++;
int numNew = a.length;
if (numNew == 0)
return false;// 长度为 0 直接返回
Object[] elementData;
final int s;
if (numNew > (elementData = this.elementData).length - (s = size))// 旧数据长度 + 新数据长度大于缓冲区大小,就扩容
elementData = grow(s + numNew);
int numMoved = s - index;// 存储长度减去 index 得出就是要移动数据的长度
if (numMoved > 0)
System.arraycopy(elementData, index,elementData, index + numNew,numMoved);// 把缓冲区从 index 移动到 index + numNew,移动长度为 numMoved
System.arraycopy(a, 0, elementData, index, numNew);// 把集合从 0 位移动到缓冲区 index 位,共移动集合的长度个数据
size = s + numNew;// 实际存储数更改为 size+ 集合长度
return true;// 返回 true
}
removeRange(int fromIndex, int toIndex) 删除介于 (包含)fromIndex 和 toIndex(不包含)的所有元素
protected void removeRange(int fromIndex, int toIndex) {if (fromIndex > toIndex) {
throw new IndexOutOfBoundsException(outOfBoundsMsg(fromIndex, toIndex));
}
modCount++;
shiftTailOverGap(elementData, fromIndex, toIndex);
}
shiftTailOverGap(Object[] es, int lo, int hi) 删除 lo(包含) 到 hi(不包含)期间的元素
private void shiftTailOverGap(Object[] es, int lo, int hi) {System.arraycopy(es, hi, es, lo, size - hi);// 从 hi 位以后的数据复制到 lo 位,共复制 size-hi 个数据
for (int to = size, i = (size -= hi - lo); i < to; i++)
es[i] = null;// 置 0
}
rangeCheckForAdd(int index) 判断是否在区间内
private void rangeCheckForAdd(int index) {if (index > size || index < 0)
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
下标越界消息
private String outOfBoundsMsg(int index) {return "Index:"+index+", Size:"+size;}
private static String outOfBoundsMsg(int fromIndex, int toIndex) {return "From Index:" + fromIndex + "> To Index:" + toIndex;}
removeAll(Collection<?> c) 删除缓冲区中,集合包含的数据
public boolean removeAll(Collection<?> c) {return batchRemove(c, false, 0, size);
}
retainAll(Collection<?> c) 保留缓冲区中,集合包含的数据
public boolean retainAll(Collection<?> c) {return batchRemove(c, true, 0, size);
}
batchRemove(Collection<?> c, boolean complement,final int from, final int end)false 是删除传入集合包含元素,true 是保留传入集合包含元素
boolean batchRemove(Collection<?> c, boolean complement,
final int from, final int end) {Objects.requireNonNull(c);
final Object[] es = elementData;
int r;
// Optimize for initial run of survivors
for (r = from;; r++) {if (r == end)// 操作长度为 0 直接返回 false
return false;
if (c.contains(es[r]) != complement)// 为 true 的时候,查找到第一个不保留位 r。为 false 时候查找到第一个要删除的位
break;
}
int w = r++;
try {for (Object e; r < end; r++)
if (c.contains(e = es[r]) == complement)// 为 true 时把在集合的元素往前移,为 false 时,不在集合的元素往前移动
es[w++] = e;
} catch (Throwable ex) {
// Preserve behavioral compatibility with AbstractCollection,
// even if c.contains() throws.
System.arraycopy(es, r, es, w, end - r);
w += end - r;
throw ex;
} finally {
modCount += end - w;
shiftTailOverGap(es, w, end);// 删除尾部元素
}
return true;
}
writeObject(java.io.ObjectOutputStream s) 输出对象
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
// Write out element count, and any hidden stuff
int expectedModCount = modCount;
s.defaultWriteObject();
// Write out size as capacity for behavioral compatibility with clone()
s.writeInt(size);
// Write out all elements in the proper order.
for (int i=0; i<size; i++) {s.writeObject(elementData[i]);// 循环输出对象
}
if (modCount != expectedModCount) {throw new ConcurrentModificationException();// 线程安全
}
}
readObject(java.io.ObjectInputStream s) 读取对象
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
// Read in size, and any hidden stuff
s.defaultReadObject();
// Read in capacity
s.readInt(); // ignored
if (size > 0) {// 数据量大于 0
// like clone(), allocate array based upon size not capacity
SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, size);
Object[] elements = new Object[size];
// Read in all elements in the proper order.
for (int i = 0; i < size; i++) {elements[i] = s.readObject();}
elementData = elements;
} else if (size == 0) {// 数据量等于 0
elementData = EMPTY_ELEMENTDATA;
} else {throw new java.io.InvalidObjectException("Invalid size:" + size);
}
}
listIterator() 返回迭代器
public ListIterator<E> listIterator() {return new ListItr(0);
}
listIterator(int index) 返回迭代器
public ListIterator<E> listIterator(int index) {rangeCheckForAdd(index);//
return new ListItr(index);
}