Method peek

ZezeJava/ZezeJava/src/main/java/Zeze/Collections/Queue.java:283–298

@return 头节点的首个值，null if empty

()

	 * @return 头节点的首个值，null if empty
	 */
	public V peek() {
		var root = getRoot();
		if (root == null)
			return null;

		var headKey = root.getHeadNodeKey();
		if (headKey.getNodeId() == 0)
			return null;
		var head = getNode(headKey);
		if (head == null)
			return null;

		@SuppressWarnings("unchecked")
		var value = (V)head.getValues().get(0).getValue().getBean();
		return value;
	}

	public long size() {
		var root = getRoot();