定义
将一个复杂对象的构建与它的表示分离,使得同样的构建过程可以创建不同的表示
你看懂了吗? 反正我是一脸懵逼
UML类图
解读:
- Product产品类: 产品抽象类
- Builder: 抽象Builder类,规划产品组建,一般是由子类实现具体的组建过程
- ConcreteBuilder: 具体的Builder类
- Director: 统一组建过程
好吧, 还是说的有点虚呀, 来一个简单例子
简单实现
Computer抽象类类：Product角色，即产品抽象类
/**
* Created by allever on 17-5-18.
* 计算机抽象类: Product角色*/
public abstract class Computer {
private String strBoard;
private String strDisplay;
private String strOS;
protected Computer(){}
/**CPU核心数*/
public void setBoard(String board){
this.strBoard = board;
}
public void setDisplay(String display){
this.strDisplay = display;
}
public void setStrOS(String os){
this.strOS = os;
}
@Override
public String toString() {
String result = "Computer:\nboard=" + strBoard + "\ndisplay = " + strDisplay + "\nOS = " + strOS;
return result;
}
}
MacBook类，具体Computer类
/**
* Created by allever on 17-5-18.
*/
public class MacBook extends Computer {
protected MacBook(){}
}
Builder抽象类
负责规范产品组建，一般是由子类实现具体的组建过程
/**
* Created by allever on 17-5-18.
* 抽象Builder类*/
public abstract class Builder {
public abstract void buildBoard(String board);
public abstract void buildDisplay(String display);
public abstract void buildOS(String os);
public abstract Computer build();
}
MacBookBuilder：具体Builder类，ConcreteBuilder角色
/**
* Created by allever on 17-5-18.
* Builder实现类*/
public class MacBookBuilder extends Builder {
private Computer computerMacBook = new MacBook();
@Override
public void buildBoard(String board) {
computerMacBook.setBoard(board);
}
@Override
public void buildDisplay(String display) {
computerMacBook.setDisplay(display);
}
@Override
public void buildOS(String os) {
computerMacBook.setStrOS(os);
}
@Override
public Computer build() {
return computerMacBook;
}
}
Director类：同一组装过程
/**
* Created by allever on 17-5-18.
* Director类： 负责构建Computer*/
public class Director {
private Builder builder = null;
public Director(Builder builder){
this.builder = builder;
}
//构建对象
public void construct(String board, String display, String os){
builder.buildBoard(board);
builder.buildDisplay(display);
builder.buildOS(os);
}
}
客户端调用
Builder builder = new MacBookBuilder();
Director director = new Director(builder);
director.construct("英特尔酷睿i7","15.6寸","Ubuntu 16.04");
Log.d(TAG, builder.build().toString());
Toast.makeText(BuildPatternsActivity.this,builder.build().toString(),Toast.LENGTH_LONG).show();
小提示
通常,Director角色会被省略,直接使用Builder构建对象,这个Builder通常为链式调用,即buildXXX()方法返回自身,return this;
修改后的Builder类
/**
* Created by allever on 17-5-18.
* 抽象Builder类*/
public abstract class Builder {
public abstract Builder buildBoard(String board);
public abstract Builder buildDisplay(String display);
public abstract Builder buildOS(String os);
public abstract Computer build();
}
MacBookBuilder:
/**
* Created by allever on 17-5-18.
* Builder实现类*/
public class MacBookBuilder extends Builder {
private Computer computerMacBook = new MacBook();
@Override
public MacBookBuilder buildBoard(String board) {
computerMacBook.setBoard(board);
return this;
}
@Override
public MacBookBuilder buildDisplay(String display) {
computerMacBook.setDisplay(display);
return this;
}
@Override
public MacBookBuilder buildOS(String os) {
computerMacBook.setStrOS(os);
return this;
}
@Override
public Computer build() {
return computerMacBook;
}
}
在客户端中的调用
Builder builder = new MacBookBuilder();
//Director director = new Director(builder);
//director.construct("英特尔酷睿i7","15.6寸","Ubuntu 16.04");
Log.d(TAG, builder.buildBoard("英特尔酷睿i7")
.buildDisplay("15.6寸")
.buildOS("Max OS")
build().toString());
现在你是不是感觉到很熟悉的呢? 就像Android中构建一个Notification对象
Notification notification = new NotificationCompat.Builder(this)
.setContentTitle("This is content title")
.setContentText("This is content text")
.setSmallIcon(R.mipmap.ic_launcher)
.setLargeIcon(BitmapFactory.decodeResource(getResources(),R.mipmap.ic_launcher))
.setWhen(System.currentTimeMillis())
//设置点击行为
.setContentIntent(pendingIntent)
//点击后消失
.setAutoCancel(true)
//设置声音
.setSound(Uri.fromFile(new File("/system/media/audio/ringtones/Luna.ogg")))
//设置震动 震动1s 静止1s 震动1s 要申明权限
.setVibrate(new long[]{0, 1000,1000,1000})
//设置呼吸灯闪烁
.setLights(Color.GREEN, 1000, 1000)
//设置默认
.setDefaults(NotificationCompat.DEFAULT_ALL)
//设置长文本
.setStyle(new NotificationCompat.BigTextStyle().bigText("An Activity is an application component that provides a screen with which users can interact in order to do something, such as dial the phone, take a photo, send an email, or view a map."))
//设置展开大图,,设置了长文本会看不到
.setStyle(new NotificationCompat.BigPictureStyle().bigPicture(BitmapFactory.decodeResource(getResources(),R.mipmap.expensive)))
//设置通知重要程度
.setPriority(NotificationCompat.PRIORITY_MAX)
.build();
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