triple.java

<设计模式-Java语言中的应用> 的源码

public class Triple {
    private static Triple[] triple = new Triple[]{
        new Triple(0),
        new Triple(1),
        new Triple(2),
    };
    private int id;
    private Triple(int id) {                                 
        System.out.println("The instance " + id + " is created.");
        this.id = id;
    }
    public static Triple getInstance(int id) {
        return triple[id];
    }
    public String toString() {
        return "[Triple id=" + id + "]";
    }
}