Java设计模式

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/creational/BuilderPattern.java

+package cn.datax.learning.design.patterns.creational;
+
+/**
+ * 建造者模式（Builder Pattern）
+ */
+public class BuilderPattern {
+
+    public static void main(String[] args) {
+        MyDate myDate = new MyDate();
+        IDateBuilder builder;
+        builder = new DateBuilder1(myDate);
+        String date1 = new Derector(builder).getDate(2066, 3, 6);
+        System.out.println(date1);
+        builder = new DateBuilder2(myDate);
+        String date2 = new Derector(builder).getDate(2067, 4, 6);
+        System.out.println(date2);
+    }
+}
+
+//首先定义一个产品类
+class MyDate {
+    String Date;
+}
+
+//然后抽象生成器，描述生成器的行为
+interface IDateBuilder {
+    IDateBuilder buildDate(int y, int m, int d);
+
+    String date();
+}
+
+//接下来是具体生成器，一个以“-”分割年月日，另一个使用空格：
+class DateBuilder1 implements IDateBuilder {
+    private MyDate myDate;
+
+    public DateBuilder1(MyDate myDate) {
+        this.myDate = myDate;
+    }
+
+    @Override
+    public IDateBuilder buildDate(int y, int m, int d) {
+        myDate.Date = y + "-" + m + "-" + d;
+        return this;
+    }
+
+    @Override
+    public String date() {
+        return myDate.Date;
+    }
+}
+
+//具体生成器
+class DateBuilder2 implements IDateBuilder {
+    private MyDate myDate;
+
+    public DateBuilder2(MyDate myDate) {
+        this.myDate = myDate;
+    }
+
+    @Override
+    public IDateBuilder buildDate(int y, int m, int d) {
+        myDate.Date = y + " " + m + " " + d;
+        return this;
+    }
+
+    @Override
+    public String date() {
+        return myDate.Date;
+    }
+}
+
+//接下来是指挥官，向用户提供具体的生成器：
+class Derector {
+    private IDateBuilder builder;
+
+    public Derector(IDateBuilder builder) {
+        this.builder = builder;
+    }
+
+    public String getDate(int y, int m, int d) {
+        builder.buildDate(y, m, d);
+        return builder.date();
+    }
+}