感想

生成器模式：封装一个复杂对象构建过程，并允许按步骤构造。

生成器模式有点：

  • 将复杂对象的创建过程封装起来。
  • 允许对象通过几个步骤来创建，并且可以改变过程（工程模式只有一个步骤）。
  • 只需指定具体生成器就能生成特定对象，隐藏类的内部结构。
  • 对象的实现可以被替换。

a.以下以旅游社的行程表为例子，定义一个行程表：

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public class Vacation {
    private ArrayList<VacationDay> mVacationDayLst;
    private Date mStDate;
    private int mDays = 0;
    private VacationDay mVacationDay;

    public Vacation(String std) {
        mVacationDayLst = new ArrayList<VacationDay>();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            mStDate = sdf.parse(std);
            mVacationDay = new VacationDay(mStDate);
            mVacationDayLst.add(mVacationDay);
            mDays++;
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }

    public void setStDate(String std) {

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            mStDate = sdf.parse(std);
        } catch (ParseException e) {
            e.printStackTrace();
        }

    }

    public Date getStDate() {
        return mStDate;
    }

    public void addDay() {

        mVacationDay = new VacationDay(nextDate(mDays));
        mVacationDayLst.add(mVacationDay);
        mDays++;
    }

    public boolean setVacationDay(int i) {
        if ((i > 0) && (i < mVacationDayLst.size())) {
            mVacationDay = mVacationDayLst.get(i);
            return true;
        }
        mVacationDay = null;
        return false;
    }

    public void setHotel(String mHotels) {
        mVacationDay.setHotel(mHotels);
    }

    public void addTicket(String ticket) {
        mVacationDay.addTicket(ticket);
    }

    public void addEvent(String event) {
        mVacationDay.addEvent(event);
    }

    public void showInfo() {
        for (int i = 0, len = mVacationDayLst.size(); i < len; i++) {
            System.out.println("** " + (i + 1) + " day**");
            System.out.println(mVacationDayLst.get(i).showInfo());
        }
    }

    private Date nextDate(int n) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(mStDate);
        cal.add(Calendar.DATE, n);
        return cal.getTime();
    }
}

b.定义当天行程：

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public class VacationDay {
    private Date mDate;
    private String mHotels;
    private ArrayList<String> mTickets = null;
    private ArrayList<String> mEvents = null;

    public VacationDay(Date date) {
        mDate = date;
        mTickets = new ArrayList<String>();
        mEvents = new ArrayList<String>();
    }

    public void setDate(Date date) {
        mDate = date;
    }

    public void setHotel(String mHotels) {
        this.mHotels = mHotels;
    }

    public void addTicket(String ticket) {
        mTickets.add(ticket);
    }

    public void addEvent(String event) {
        mEvents.add(event);
    }

    public String showInfo() {
        StringBuilder stb = new StringBuilder();
        stb.append("Date:" + mDate.toString() + "\n");
        stb.append("Hotel:" + mHotels + "\n");
        stb.append("Tickets:" + mTickets.toString() + "\n");
        stb.append("Events" + mEvents.toString() + "\n");

        return stb.toString();
    }
}

c.定义一个抽象的生成器：

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public abstract class AbsBuilder {

    public Vacation mVacation;

    public AbsBuilder(String std) {
        mVacation = new Vacation(std);
    }

    public abstract void buildvacation();

    public abstract void buildDay(int i);

    public abstract void addHotel(String hotel);

    public abstract void addTicket(String ticket);

    public abstract void addEvent(String tvent);

    public Vacation getVacation() {

        return mVacation;

    }
}

d1.定义3天的行程表：

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public class Builder3d extends AbsBuilder {

    public Builder3d(String std) {
        super(std);
    }

    @Override
    public void buildDay(int i) {
        mVacation.setVacationDay(i);
    }

    @Override
    public void addHotel(String hotel) {
        mVacation.setHotel(hotel);
    }

    @Override
    public void addTicket(String ticket) {
        mVacation.addTicket(ticket);
    }

    @Override
    public void addEvent(String event) {
        mVacation.addEvent(event);
    }

    @Override
    public void buildvacation() {
        addTicket("Plane Ticket");
        addEvent("Fly to Destination");
        addEvent("Supper");
        addEvent("Dancing");
        addHotel("Four Seasons");

        mVacation.addDay();
        addTicket("Theme Park");
        addEvent("Bus to Park");
        addEvent("lunch");
        addHotel("Four Seasons");

        mVacation.addDay();

        addTicket("Plane Ticket");
        addEvent("City Tour");
        addEvent("Fly to Home");

    }

}

d2.定义4天的行程表：

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public class Builder4d extends AbsBuilder {

    public Builder4d(String std) {
        super(std);
    }

    @Override
    public void buildDay(int i) {
        mVacation.setVacationDay(i);
    }

    @Override
    public void addHotel(String hotel) {
        mVacation.setHotel(hotel);
    }

    @Override
    public void addTicket(String ticket) {
        mVacation.addTicket(ticket);
    }

    @Override
    public void addEvent(String event) {
        mVacation.addEvent(event);
    }

    @Override
    public void buildvacation() {

        addTicket("Plane Ticket");
        addEvent("Fly to Destination");
        addEvent("Supper");
        addHotel("Hilton");

        mVacation.addDay();
        addTicket("Zoo Ticket");
        addEvent("Bus to Zoo");
        addEvent("Feed animals");
        addHotel("Hilton");

        mVacation.addDay();
        addTicket("Beach");
        addEvent("Swimming");
        addHotel("Home inn");

        mVacation.addDay();
        addTicket("Plane Ticket");
        addEvent("Fly to Home");
    }

}

d3.定义自定义的行程表：

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public class BuilderSelf {
    public Vacation mVacation;

    private String std;

    public BuilderSelf(String std) {
        this.std = std;
        //        mVacation = new Vacation(std);
    }

    public BuilderSelf addDay() {
        if(mVacation == null){
            mVacation = new Vacation(std);
        }else{
            mVacation.addDay();
        }

        return this;
    }

    public BuilderSelf buildDay(int i) {
        mVacation.setVacationDay(i);
        return this;
    }

    public BuilderSelf addHotel(String hotel) {
        mVacation.setHotel(hotel);
        return this;
    }

    public BuilderSelf addTicket(String ticket) {
        mVacation.addTicket(ticket);
        return this;
    }

    public BuilderSelf addEvent(String event) {
        mVacation.addEvent(event);
        return this;
    }

    public Vacation getVacation() {
        return mVacation;
    }
}

e.定义一个在代办人：

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public class Director {
    private AbsBuilder builder;

    public Director(AbsBuilder builder) {
        this.builder = builder;
    }

    public void setBuilder(AbsBuilder builder) {
        this.builder = builder;
    }

    public void construct() {
        builder.buildvacation();
        builder.getVacation().showInfo();
    }
}

f.客户端使用：

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public class App {

	public static void main(String[] args) {

		Director mDirector = new Director(new Builder4d("2015-12-29"));
		mDirector.construct();

		mDirector.setBuilder(new Builder3d("2015-8-30"));
		mDirector.construct();

		testself();
	}

	/**
	 * 自定义
	 */
	public static void testself() {

		BuilderSelf builder = new BuilderSelf("2015-9-29");

		builder.addDay().addTicket("Plane Ticket").addEvent("Fly to Destination")
				.addEvent("Supper").addHotel("Hilton");

		builder.addDay().addTicket("Zoo Ticket").addEvent("Bus to Zoo")
				.addEvent("Feed animals").addHotel("Home Inn");

		builder.addDay();
		builder.addTicket("Beach");
		builder.addEvent("Swimming");
		builder.addHotel("Home inn");

		builder.addDay().addTicket("Plane Ticket").addEvent("Fly to Home");
		builder.getVacation().showInfo();
	}

}