设计模式-享元模式

享元模式

定义：运用共享技术有效地支持大量细粒度的对象

优点：如果系统有大量类似的对象，可以节省大量的内存和CPU资源

实现

场景：假如我要开发一款游戏，然后游戏里面的地图有很多树木

这个时候，我们不可能创建几万个树的对象

Tree

@Data
@AllArgsConstructor
@ToString
public class Tree {
    private final String name;
}

TreeNode

@Data
@AllArgsConstructor
public class TreeNode {
    private final Tree tree;
    private int x;
    private int y;
}

TreeFactory

public class TreeFactory {
    private static ConcurrentHashMap<String, Tree> map = new ConcurrentHashMap<>();
    public static Tree getTree(String name){
        if(map.containsKey(name)){
            return map.get(name);
        }
        return null;
    }

    public static void addTree(String name){
        map.put(name,new Tree(name));
    }
}

主函数

public static void main(String[] args) {
    TreeFactory.addTree("梧桐树");
    TreeFactory.addTree("香樟树");
    TreeFactory.addTree("银杏树");
    TreeFactory.addTree("面包树");
    TreeNode treeNode1 = new TreeNode(TreeFactory.getTree("梧桐树"),1,1);
    TreeNode treeNode2 = new TreeNode(TreeFactory.getTree("梧桐树"),1,2);
    TreeNode treeNode3 = new TreeNode(TreeFactory.getTree("梧桐树"),1,3);
}