设计模式-享元模式

/**
 * 享元模式
 *
 * 运用共享技术有效地支持大量细粒度的对象
 *
 * 优点：
 * 如果系统中有大量类似的对象，可以节省大量的内存和cpu资源
 *
 */
public class TestFlyweight {
    public static void main(String[] args) {
        TreeNode treeNode = new TreeNode(4, 5, TreeFactory.getTree("suntree", "good tree"));
        TreeNode treeNode2 = new TreeNode(6, 7, TreeFactory.getTree("suntree", "good tree"));

        TreeNode treeNod3 = new TreeNode(4, 5, TreeFactory.getTree("suncodetree", "good tree"));
        TreeNode treeNode4 = new TreeNode(6, 7, TreeFactory.getTree("suncodetree", "good tree"));
    }
}

/**
 * Tree的构建工厂
 * 用一个 HashMap 来存放每次新生成的对象。每次需要一个对象的时候，
 * 先到 HashMap 中看看有没有，如果没有，再生成新的对象，然后将这个对象放入 HashMap 中。
 */
public class TreeFactory {
    private static Map<String,Tree> treeMap=new ConcurrentHashMap<>();

    public static Tree getTree(String name,String data){
        System.out.println("tree的名字"+name);
        if(treeMap.containsKey("xxx")){
            return treeMap.get(name);
        }

        Tree tree=new Tree(name,data);
        treeMap.put(name,tree);

        return tree;
    }
}

@Data
@Builder
@ToString
public class Tree {
    private String name;
    private String data;
}

@Data
@Builder
@AllArgsConstructor
@ToString
public class TreeNode {
    int x;
    int y;
    Tree tree;

}