设计模式10---建造者模式
设计模式就是对相同部分进行归纳,归并,不仅仅包括对象(继承,多态)也包括业务逻辑,(流程结果等),以及数据存储(使用不同数据库)。
使各个部分独立,解耦。使UI,业务逻辑,数据可以各自独立,更新等。
对建造者模式而言就是通过构建流程与具体表现的分离,抽象出构建过程。对相同或类似的构建过程进行分离,从而达到复用的目的。
Director 制定product产生的顺序,各个部分准备好了以后,可以由实体类concretebuilder产生product。
public interface Builder { void buildPartA(); void buildPartB(); void buildPartC(); Product getResult(); } //具体建造工具 public class ConcreteBuilder implements Builder { Part partA, partB, partC; public void buildPartA() { //这里是具体如何构建partA的代码 }; public void buildPartB() { //这里是具体如何构建partB的代码 }; public void buildPartC() { //这里是具体如何构建partB的代码 }; public Product getResult() { //返回最后组装成品结果 }; } //建造者 public class Director { private Builder builder; public Director( Builder builder ) { this.builder = builder; } public void construct() { builder.buildPartA(); builder.buildPartB(); builder.buildPartC(); } } public interface Product { } public interface Part { } 复制代码 下面是调用builder的方法: ConcreteBuilder builder = new ConcreteBuilder(); Director director = new Director( builder ); director.construct(); Product product = builder.getResult();
director.construct();是按一定的流程产生了product或者product的部件。
所以对于有相同的操作过程,但是顺序不同,或者相差几步的来说,可以通过不同的 Director 来实现。如果使用工厂方法,ConcreteBuilder 对于上层UI是透明的。
使用抽象工厂模式封装后的代码:
public interface IBuilder { void buildA(); void buildB(); void buildC(); Productor getResult(); }
public class ConcreateBuilder implements IBuilder { private Productor _mProductor = new Productor(); @Override public void buildA() { // TODO Auto-generated method stub System.out.println("small A"); _mProductor.setPartA("small A"); } @Override public void buildB() { // TODO Auto-generated method stub System.out.println("middle B"); _mProductor.setPartB("middle B"); } @Override public void buildC() { // TODO Auto-generated method stub System.out.println("large C"); _mProductor.setPartC("large C"); } @Override public Productor getResult() { // TODO Auto-generated method stub return _mProductor; } }
public class ConcreateBuilderB implements IBuilder { private Productor _mProductor = new Productor(); @Override public void buildA() { // TODO Auto-generated method stub System.out.println("middle A"); _mProductor.setPartA("middle A"); } @Override public void buildB() { // TODO Auto-generated method stub System.out.println("small B"); _mProductor.setPartB("small B"); } @Override public void buildC() { // TODO Auto-generated method stub System.out.println("small C"); _mProductor.setPartC("small C"); } @Override public Productor getResult() { return _mProductor; } }
public class Director { private IBuilder builder; public Director(IBuilder mBuilder) { builder = mBuilder; } public void construct() { builder.buildA(); builder.buildB(); builder.buildC(); } }
public class Productor { private String partA; private String partB; private String partC; /** * @param partA the partA to set */ public void setPartA(String partA) { this.partA = partA; } /** * @param partB the partB to set */ public void setPartB(String partB) { this.partB = partB; } /** * @param partC the partC to set */ public void setPartC(String partC) { this.partC = partC; } /* (non-Javadoc) * @see java.lang.Object#toString() */ @Override public String toString() { // TODO Auto-generated method stub return (partA+"\t"+partB+"\t"+partC); } }
反射+抽象工厂模式:
public class BuildFactory { private static final String AssemblyName = "com.jayfulmath.designpattern.builder"; private static final String realClass = "ConcreateBuilder"; public static IBuilder operator() { IBuilder result = null; String className =AssemblyName+"."+realClass; try { Class<?> c = Class.forName(className); Constructor<?> ct = c.getConstructor(); result = (IBuilder) (ct.newInstance()); } catch (NoSuchMethodException |ClassNotFoundException | InstantiationException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) { // TODO Auto-generated catch block e.printStackTrace(); } return result; } }
/*对于构建过程,可以使用Director来固定 *对于实现类ConcreateBuilder and ConcreateBuilderB, 可以使用抽象工厂模式的方式进行封装. * * */ public class BuildMain extends BasicExample { @Override public void startDemo() { // TODO Auto-generated method stub IBuilder builder = BuildFactory.operator(); Director mDirector = new Director(builder); mDirector.construct(); Productor mProductor = builder.getResult(); System.out.println("productor:"+mProductor.toString()); } }
可以看到,main方法只要知道IBuilder以及director,由mDirector.construct();来构造,就可以获得Productor .
posted on 2014-12-01 14:33 Joyfulmath 阅读(161) 评论(0) 编辑 收藏 举报