设计模式学习—组合实体模式(Composite Entity Design Pattern)

一、我的理解

该模式是EJB开发时用到的一种模式。目前我的理解是该模式的作用是将各个细粒度的业务单独分割出来，然后由一个粗粒度的类来管理这些实体类。

二、实现方式

每个业务对应一个实体类，然后由一个粗粒度的类来生成和管理这些类

三、实例

Java实例

DependencyObject1类：实体类一

package com.study.dp.compositeentity;public class DependencyObject1 {    private String data;    public String getData() {        return data;    }    public void setData(String data) {        this.data = data;    }}

DependencyObject2类：实体类二

package com.study.dp.compositeentity;public class DependencyObject2 {    private String data;    public String getData() {        return data;    }    public void setData(String data) {        this.data = data;    }}

CoarseGrainedObject类：粗粒度管理类

package com.study.dp.compositeentity;public class CoarseGrainedObject {    DependencyObject1 do1 = new DependencyObject1();    DependencyObject2 do2 = new DependencyObject2();        public void setData(String data1, String data2) {        do1.setData(data1);        do2.setData(data2);    }        public String[] getData() {        return new String[] {do1.getData(), do2.getData()};    }    }

CompositeEntity类：组合实体类，通过调用粗粒度对象来管理实体

package com.study.dp.compositeentity;public class CompositeEntity {    private CoarseGrainedObject cgo = new CoarseGrainedObject();        public void setData(String data1, String data2) {        cgo.setData(data1, data2);    }        public String[] getData() {        return cgo.getData();    }    }

Client类：客户端类

package com.study.dp.compositeentity;public class Client {    private CompositeEntity compositeEntity = new CompositeEntity();        public void printData() {        for(int i=0; i<compositeEntity.getData().length; i++) {            System.out.println("Data: "+compositeEntity.getData()[i]);        }    }        public void setData(String data1, String data2) {        compositeEntity.setData(data1, data2);    }    }

Demo类：测试类

package com.study.dp.compositeentity;public class Demo {    public static void main(String[] args) {        Client client = new Client();        client.setData("Test", "Data");        client.printData();        client.setData("Second Test", "Data1");        client.printData();    }    }

四、应用场景