设计模式之抽象工厂模式

    在上一篇博客中我们使用了工厂模式来设计一个网上车辆交易系统。在那个样例中仅仅有汽车这一种单一类型的商品。那么，假设有多种类型的商品。还能用工厂方法模式吗？举个样例，如今有个网上服装买卖系统。有三种服装---鞋、套装和衬衫，当中又分为男鞋女鞋、男套装和女套装、男衬衫和女衬衫。即例如以下商品：

   依照上节中说到的工厂方法模式，应该这样设计。使用三个工厂来创建三个对象：

    这样做也能实现。可是工厂类有点多吧，并且在client中将会有非常多的条件语句，有没有什么更好的办法呢？我们在分析看看。商品有三种，性别相应着男、女，那么我们为什么不从还有一个角度来思考问题，不再建立生产shoes、shirt和suit的工厂。而是建立生产男人的衣服工厂ManCloseFactory和生产女人衣服的工厂WomanCLoseFactory。例如以下设计：

    类图设计好了。如今仅仅须要两个工厂就能搞定了，那么编代码试试吧：

shirt接口：

public interface Shirt {
	public String getInfo();
}

suit接口：

public interface Suit {
	public String getInfo();
}

shoes接口：

public interface Shoes {
	public String getInfo();
}

ManShirt类：

public class ManShirt implements Shirt {

	@Override
	public String getInfo() {
		// TODO Auto-generated method stub
		String info = "男  衬衫";
		return info;
	}
}

WomanShirt类：

public class WomanShirt implements Shirt {

	@Override
	public String getInfo() {
		// TODO Auto-generated method stub
		String info = "女  衬衫";
		return info;
	}
}

ManSuit类：

public class ManSuit implements Suit {

	@Override
	public String getInfo() {
		// TODO Auto-generated method stub
		String info = "男  套装";
		return info;
	}
}

WomanSuit类：

public class WomanSuit implements Suit {

	@Override
	public String getInfo() {
		// TODO Auto-generated method stub
		String info = "女  套装";
		return info;
	}
}

ManShoes类：

public class ManShoes implements Shoes {

	@Override
	public String getInfo() {
		// TODO Auto-generated method stub
		String info = "男  鞋";
		return info;
	}
}

WomanShoes类：

public class WomanShoes implements Shoes {

	@Override
	public String getInfo() {
		// TODO Auto-generated method stub
		String info = "女  鞋";
		return info;
	}
}

工厂类的基类：

public abstract class CloseFactory {
	public static final String MAN = "男";
	public static final String WOMAN = "女";
	
	public abstract Shoes getShoes();
	public abstract Suit getSuit();
	public abstract Shirt getShirt();

	public static CloseFactory getCloseFactory(String Sex){
		CloseFactory CF = null;
		if(Sex.equals(MAN)){
			CF = new ManCloseFactory();
		}else if(Sex.equals(WOMAN)){
			CF = new WomanCloseFactory();
		}
		return CF;
	}
}

男服生产工厂，ManCloseFactory：

public class ManCloseFactory extends CloseFactory {

	@Override
	public Shoes getShoes() {
		// TODO Auto-generated method stub
		return new ManShoes();
	}

	@Override
	public Suit getSuit() {
		// TODO Auto-generated method stub
		return new ManSuit();
	}

	@Override
	public Shirt getShirt() {
		// TODO Auto-generated method stub
		return new ManShirt();
	}
}

女服生产工厂，WomanCloseFactory：

public class WomanCloseFactory extends CloseFactory {

	@Override
	public Shoes getShoes() {
		// TODO Auto-generated method stub
		return new WomanShoes();
	}

	@Override
	public Suit getSuit() {
		// TODO Auto-generated method stub
		return new WomanSuit();
	}

	@Override
	public Shirt getShirt() {
		// TODO Auto-generated method stub
		return new WomanShirt();
	}
}

client：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;

public class clientGUI extends JFrame implements ActionListener{

	private String SHOES = "鞋";
	private String SHIRT = "衬衫";
	private String SUIT = "套装";
	
	private String MAN = "男";
	private String WOMAN = "女";
	
	private JLabel labelShowSex;
	private JLabel labelShowType;
	
	private JTextArea textShowInfo;
	private JComboBox ChoiceSex;
	private JComboBox ChoiceType;
	
	private JButton BtnOK;
	private JButton BtnExit;
	
	private JPanel panelNorth;
	private JPanel panelCenter;
	private JPanel panelSouth;
	
	public void initComponents(){
		labelShowSex = new JLabel("请选择性别：");
		labelShowType = new JLabel("请选择服饰：");
		
		textShowInfo = new JTextArea();
		textShowInfo = new JTextArea();
		textShowInfo.setColumns(20);
		textShowInfo.setRows(100);
		textShowInfo.setBackground(Color.PINK);
		ChoiceSex = new JComboBox();
		ChoiceSex.addItem(MAN);
		ChoiceSex.addItem(WOMAN);
		
		ChoiceType = new JComboBox();
		ChoiceType.addItem(SHOES);
		ChoiceType.addItem(SHIRT);
		ChoiceType.addItem(SUIT);
		
		BtnOK = new JButton("OK");
		BtnOK.addActionListener(this);
		BtnExit = new JButton("EXIT");
		BtnExit.addActionListener(this);
		
		panelNorth = new JPanel();
		panelCenter = new JPanel();
		panelSouth = new JPanel();
	}
	
	public void panelAddComponenets(){
		panelNorth.add(labelShowSex);
		panelNorth.add(ChoiceSex);
		
		panelNorth.add(labelShowType);
		panelNorth.add(ChoiceType);
		
		panelCenter.add(textShowInfo);
		panelSouth.add(BtnOK);
		panelSouth.add(BtnExit);
	}
	
	public void mainFrameAddPanel(){
		this.add("North", panelNorth);
		this.add("Center", panelCenter);
		this.add("South", panelSouth);
	}
	
	public void mianFramSet(){
		Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
		this.setLocation((d.width - this.getSize().width)/2, (d.height - this.getSize().height)/2);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setSize(300, 200);
		this.setVisible(true);
	}

	public clientGUI(){
		initComponents();
		panelAddComponenets();
		mainFrameAddPanel();
		mianFramSet();
	}
	@Override
	public void actionPerformed(ActionEvent e) {
		// TODO Auto-generated method stub
		if(e.getSource() == BtnOK){
			String Sex = ChoiceSex.getSelectedItem().toString();
			String Type = ChoiceType.getSelectedItem().toString();
			CloseFactory cf =  CloseFactory.getCloseFactory(Sex);//依据性别调用对应的工厂
			if(Type.equals(SHIRT)){//依据类型生产对应的产品
				Shirt s = cf.getShirt();
				String info = s.getInfo();
				textShowInfo.setText(info);
			}else if(Type.equals(SHOES)){
				Shoes s = cf.getShoes();
				String info = s.getInfo();
				textShowInfo.setText(info);
			}else if(Type.equals(SUIT)){
				Suit s = cf.getSuit();
				String info = s.getInfo();
				textShowInfo.setText(info);
			}
		}
		if(e.getSource() == BtnExit){
			System.exit(0);
		}
	}
}

測试：

public class mian {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		clientGUI cGUI = new clientGUI();
	}

}

    这样设计是不是好多了。！

！

    总结一下，抽象工厂模式应用在产品类别不唯一的情况，而工厂模式应用在产品类别单一的情况。再画一下抽象工厂模式的设计图：

    上节中说到。工厂方法符合开闭原则，可是抽象工厂方法仅仅是部分的符合开闭原则，举个样例：