public E remove(int index) { checkElementIndex(index); return unlink(node(index)); }
publicbooleanremove(Object o) { if (o == null) { for (Node<E> x = first; x != null; x = x.next) { if (x.item == null) { unlink(x); returntrue; } } } else { for (Node<E> x = first; x != null; x = x.next) { if (o.equals(x.item)) { unlink(x); returntrue; } } } returnfalse; }
E unlink(Node<E> x){ finalEemelemt= x.item; final Node<E> next = x.next; final Node<E> prev = x.prev; if (prev == null) { first = next; } else { prev.next = next; x.prev = null; }
if (next == null) { last = prev; } else { next.prev = prev; x.next = null; }
publicbooleanremove(Object o) { if (o == null) { for (intindex=0; index < size; index++) if (elementData[index] == null) { fastRemove(index); returntrue; } } else { for (intindex=0; index < size; index++) if (o.equals(elementData[index])) { fastRemove(index); returntrue; } } returnfalse; }
public E remove(int index) { rangeCheck(index);
modCount++; EoldValue= elementData(index);
intnumMoved= size - index - 1; if (numMoved > 0) System.arraycopy(elementData, index+1, elementData, index, numMoved); elementData[--size] = null; // clear to let GC do its work
voidlinkLast(E e) { final Node<E> l = last; final Node<E> newNode = newNode<>(l, e, null); last = newNode; if (l == null) first = newNode; else l.next = newNode; size++; modCount++; }
ArrayList add方法扩容源码如下:
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privatevoidgrow(int minCapacity) { // overflow-conscious code intoldCapacity= elementData.length; intnewCapacity= 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); }