Java设计模式三
建造者模式
当我们思考通过复杂的零件来生成一个完整的产品时，就用到了今天要说的主题-建造者模式，下面我们实际的代码来分析建造者模式的设计
假设飞机起飞需要有多个步骤，但是每种型号的飞机起飞的步骤又不相同，这时我们想要建造一个可以起飞多种型号飞机的工程。
1.首先我们先预先定义一个抽象的飞机起飞类，此类中包含启动发动机、轮滑、推力式发射、弹射、起飞等操作。
public abstract class Airplane {
//定义每个步骤的执行顺序
private ArrayList<String> sequence = new ArrayList<>();
//飞机打开发动机
protected abstract void start();
//飞机滑行
protected abstract void glide();
//飞机被推力发射
protected abstract void emit();
//飞机弹射
protected abstract void popup();
//开始起飞
protected abstract void hopoff();
//设定传递方法
final public void setSequence(ArrayList<String> sequence) {
this.sequence = sequence;
}
//飞机起飞步骤
final public void run() {
for(int i = 0;i<this.sequence.size();i++) {
String actionName = this.sequence.get(i);
if(actionName.equalsIgnoreCase("start")) {
this.start();
}else if(actionName.equalsIgnoreCase("glide")) {
this.glide();
}else if(actionName.equalsIgnoreCase("emit")) {
this.emit();
}else if(actionName.equalsIgnoreCase("popup")) {
this.popup();
}else if(actionName.equalsIgnoreCase("hopoff")) {
this.hopoff();
}
}
}
}
class J10 extends Airplane{
@Override
protected void start() {
// TODO Auto-generated method stub
System.out.println("J10启动发动机");
}
@Override
protected void glide() {
// TODO Auto-generated method stub
System.out.println("J10开始滑行");
}
@Override
protected void emit() {
// TODO Auto-generated method stub
System.out.println("J10被发射");
}
@Override
protected void popup() {
// TODO Auto-generated method stub
System.out.println("J10被弹射");
}
@Override
protected void hopoff() {
// TODO Auto-generated method stub
System.out.println("J10成功起飞");
}
}
class J15 extends Airplane{
@Override
protected void start() {
// TODO Auto-generated method stub
System.out.println("J15启动发动机");
}
@Override
protected void glide() {
// TODO Auto-generated method stub
System.out.println("J15开始滑行");
}
@Override
protected void emit() {
// TODO Auto-generated method stub
System.out.println("J15被发射");
}
@Override
protected void popup() {
// TODO Auto-generated method stub
System.out.println("J15被弹射");
}
@Override
protected void hopoff() {
// TODO Auto-generated method stub
System.out.println("J15成功起飞");
}
}
2.定义建造类-定义每种类型飞机的起飞步骤
/**
* 飞机组装类
*
*/
public abstract class AirBuilder {
public abstract void setSequence(ArrayList<String> sequence);
//设置飞机的不同型号
public abstract Airplane getAirplane();
}
class J10Builder extends AirBuilder{
private J10 j10 = new J10();
@Override
public void setSequence(ArrayList<String> sequence) {
// TODO Auto-generated method stub
this.j10.setSequence(sequence);
}
@Override
public Airplane getAirplane() {
// TODO Auto-generated method stub
return this.j10;
}
}
class J15Builder extends AirBuilder{
private J15 j15 = new J15();
@Override
public void setSequence(ArrayList<String> sequence) {
// TODO Auto-generated method stub
this.j15.setSequence(sequence);
}
@Override
public Airplane getAirplane() {
// TODO Auto-generated method stub
return this.j15;
}
}
3.开始起飞测试
/**
* 飞行测试
*
*/
public class Client {
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList<String> sequence1 = new ArrayList<>();
sequence1.add("start");//设置J10开始发动
sequence1.add("glide");//开始滑行
sequence1.add("hopoff");//成功起飞
ArrayList<String> sequence2 = new ArrayList<>();
sequence2.add("start");//设置J150开始发动
sequence2.add("emit");//开始弹射
sequence2.add("hopoff");//成功起飞
//实例化一架J10
J10Builder j10builder = new J10Builder();
j10builder.setSequence(sequence1);
J10 j10 = (J10) j10builder.getAirplane();
j10.run();
System.out.println();
J15Builder j15Builder = new J15Builder();
j15Builder.setSequence(sequence2);
J15 j15 = (J15) j15Builder.getAirplane();
j15.run();
}
}
运行结果：
批量建造
/**
* 飞机场-定义每种型号飞机的具体起飞方法
*/
public class AirPort {
private ArrayList<String> sequence = new ArrayList<>();//定义起飞步骤顺序
private J10Builder j10builder = new J10Builder();
private J15Builder j15builder = new J15Builder();
/**
* 定义J10起飞步骤
* @return J10
*/
public J10 getJ10model() {
this.sequence.clear();
sequence.add("start");//设置J10开始发动
sequence.add("glide");//开始滑行
sequence.add("hopoff");//成功起飞
this.j10builder.setSequence(sequence);
return (J10)this.j10builder.getAirplane();
}
/**
* 定义J150起飞步骤
* @return J15
*/
public J15 getJ15model() {
this.sequence.clear();
sequence.add("start");//设置J15开始发动
sequence.add("emit");//弹射
sequence.add("hopoff");//成功起飞
this.j15builder.setSequence(sequence);
return (J15)this.j15builder.getAirplane();
}
}
定义测试类
public class NewClient {
public static void main(String[] args) {
AirPort airport = new AirPort();
for (int i = 0; i<=20; i++) {
System.out.println("第"+i+"架J10开始起飞");
airport.getJ10model().run();
}
for (int i = 0; i<=30; i++) {
System.out.println("第"+i+"架J15开始起飞");
airport.getJ15model().run();
}
}
}
运行结果：
以上代码可以细细品味这样设计的好处，建造者模式便于我们控制细节，并且使得程序容易扩展。
