NotifyObservers ();Visitor pattern decouples the data structure from the operations acting on the structure, making the operation set relatively free to evolve. Visitor pattern is suitable for systems with relatively stable data structure and easy change of algorithm. Because visitor mode makes it easy to increase algorithm operation. If system data structure objects are easy to change and new data objects are often added, visitor mode is not suitable. The advantage of visitor mode is that it is easy to add operations, because adding operations means adding new visitors. Visitor mode centralizes the relevant behaviors into one visitor object, and its changes do not affect the system data structure. Its disadvantage is that it is difficult to add new data structures. -From EncyclopediaPrivate Source source;围绕主人公墨弦（李玉洁饰）阴错阳差走入仙界学院的考场，之后被仙界录取的故事展开。剧中仙界新生们各个身怀仙法技能 ，初入仙界学习仙术的墨弦在男主炽银（刘海宽饰）、蓝岳（严子贤饰）的帮助下逐步适应了仙界生活，并经过不断冒险历练最终改变自己获得新生。本剧的主演阵容均为演艺界新人，李玉洁灵动可人，刘海宽俊朗帅气、严子贤风趣幽默，充满了青春气息。Squat down, grab bars, lift, shoulder support, bow legs, clean and jerk... on the afternoon of the 8th, when the peninsula reporter came to the weightlifting training hall of the city sports school, the afternoon training class had already begun, and more than 20 female athletes were silently repeating their exercises and lifting barbells again and again. Different from the traditional impression of reporters, weightlifters are short and stout. Some of the girls here are over 1.70 meters tall. Most of them are well-proportioned, with beautiful hips and tight arms. Only a few of them are tall and stout, while the rest can't see any trace of stout. "Because China used to do weightlifting at small levels, people saw the success of 48kg and 52kg athletes, so they took it for granted that weightlifting would make people grow short, but in fact scientific practice would not affect children's height development. Just imagine, even in daily life, how tall can a person weightlifting about 100kg be? Plus muscular will appear stout, but this does not mean that all weightlifters are stout. Five or six little girls in our team are over 1.70 meters tall, and some boys are nearly 1.90 meters tall. " Liu Eryong, coach of the women's weightlifting team, told reporters that weightlifting not only did not affect the height of the children, but also did not destroy their figure. "As you can see, because of the long-term squat practice, the children's thighs and buttocks are very beautiful. Some small fat people have lost more than 10 kg in a few months and their muscle lines look better. With the deepening of scientific training, weightlifting is no longer the sport that people think destroys their bodies. "内地青年郭天豪是一名动物饲养员。在被未婚妻悔婚后他辞职来到海南，寻找儿时爷爷口中象征幸福的“会微笑的猫头鹰”。精灵般神秘女孩吴梦晨的出现，打破了天豪在海南平淡的生活。天豪逐渐被这个敢想敢干，胆大妄为的姑娘所吸引。她对大自然的态度和对生命的尊重，把天豪从自我封闭的囚笼中释放了出来。两人相遇、相识、相知、相倾，可正在天豪决心鼓起勇气追求爱的时候，梦晨却消失了。原来梦晨是一名XP症（色素性干皮症）患者，生命只有7300天（二十岁），而且不能见阳光，可她为了完成和天豪许下的承诺，人生第一次看到了初升的太阳，也因此导致病情恶化，不久于人世。得知真相的天豪决定用爱来挽救梦晨。一场盛大的婚礼即将在海边举行，然而新娘却没有出现……En of Love，学长的爱情攻心计，又名：齿轮之爱，包含3个爱情故事。 故事一：En of Love: TOSSARA Gun Tossakan是一名医学系的新生，聪明又高大帅气，他从高中开始就喜欢上了Bar Sarawat。Bar Sarawat是工程学院一名非 常受欢迎的大三学生，而且是其中的佼佼者。 因为Gun高中时候信守跟妈妈说的承诺——上完高中才能谈恋爱，所以他高中时没有能确认对Bar的感觉。但是他上大学之后，他所有的计划都被命运打乱了。 世界很小，大学更小。成为受欢迎的学生之后，Gun和Bar产生了一次又一次碰撞。也许Bar也有一个曾经没有说出口的告白？ 故事二：En of Love: This is Love Story 这个爱情故事讲的是一个工程学院的花花公子Neur爱上Gun Tossakan在读高中的弟弟Pra-Ram之后，他如何获取Pra-Ram的芳心和Gun Tossakan的同意。 故事三：En of Love: Love Mechanics 这个爱情故事始于社团的一个晚上。工程学院的Mark，因失恋喝得烂醉；Wee也错把Mark当成他的暗恋对象Bar Sarawut。这是一个关于失恋的两个人之间的爱情故事。
