desingpattern_builderfactory.java

* 程序名称：食品价格计算 * 程序说明： * 1. 将所购食品分为主食

/*****************************************************************
 *
 *            Design Pattern: Builder with Factory
 *
 *****************************************************************
 *
 * 程序名称：食品价格计算
 * 程序说明：
 * 1. 将所购食品分为主食，水果和饮料三组，在左面板目显示。
 * 2. 点击任何一个组名，右面板目显示其组内所包括的具体食物。
 * 3. 通过使用Builder方法,来控制对不同组食物，右面板的不同显示方式。
 * 4. 在底部面板显示各组内食品的总价格。
 * 5. 若选择中右面板中的特定食品，只显示所选中条目所代表的价格。
 * 6. 若选择中右面板中的全部食品，则其个底部面板上的总价格相等。
 *
 *****************************************************************
 * Author:   LU Hongyu (68721123, 62755625)
 * 
 * Class:    Advanced Program Design, Peking Univ.
 * Teacher:  GUO Yingshou
 *
 * Purpose: 
 * 1. Demonstrating the Power of Design Pattern and Java.
 * 2. Display different panel of different food group.
 * 3. Caculating the total cost in one food group.
 * 4. Caculating the cost of the selected items in a group.
 *
 * Run: javac LuhyBuilder.java, java LuhyBuilder 
 *
 * TabSize:  4 Characters 
 * Complier: JDK 1.2 on Windows98
 * Date:	 Jan, 23, 2002
 * 
 *****************************************************************/


//----------------------------------------------------------------
import java.awt.*;
import java.awt.List;
import java.awt.event.*;
import java.util.*;
import java.util.Vector;;
//----------------------------------------------------------------


public class lbd.java
{
	public static void main(String args[])
	{
		new CostBuilder();
	}
}
//----------------------------------------------------------------


// class for data communication using Vector
class MyFood extends Vector
{
	String name;
	float price;
	
	MyFood()
	{
	}
	
	MyFood(String nameTmp, float priceTmp)
	{
		name = nameTmp;
		price = priceTmp;
	}
}	
//----------------------------------------------------------------


// abstract class for listBox, btnBox, checkBox-Choice class
abstract class MultiChoice
{
	MyFood choices;
	
	public MultiChoice(MyFood choiceList)
	{
		choices = choiceList;	
	}

	abstract public Panel getUI(); //return a Panel of components

}
//----------------------------------------------------------------


// class for creating ListBoxChoice
class ListBoxChoice extends MultiChoice implements ItemListener
{
	List aList; 
	Label aLabel; 


	public ListBoxChoice(MyFood choices)
	{
		super(choices);
	}

	
	// create a panel containing a ListBox
	public Panel getUI()
	{
		Panel p = new Panel();
		p.setLayout(new BorderLayout());
		
		aLabel = new Label();
		aLabel.setBackground(Color.green);
		p.add("South", aLabel);
		
		aList = new List(choices.size()+2); 
		aList.setMultipleMode(true); 		
		aList.addItemListener(this);
		p.add(aList);
		
		for (int i=0; i< choices.size(); i++)
		{
			MyFood food = (MyFood) choices.get(i);
			aList.add(food.name);
		}
		
		return p; 
	}

	
	// event hanlder for selecting the list items
	public void itemStateChanged(ItemEvent ievt)
	{	
		List lsTmp;
		int lsSelIndex[];
		
		if(ievt.getItemSelectable() instanceof List)
		{
			lsTmp = (List) (ievt.getItemSelectable());
			lsSelIndex = lsTmp.getSelectedIndexes();
			
			// add money together for the selected items
			float sum = (float) 0.0;
			for (int i=0; i<lsSelIndex.length; i++)
			{
				int j = lsSelIndex[i];
				MyFood food = (MyFood) choices.get(j);
				sum = sum + food.price;
			}
			aLabel.setText(("  " + new Float(sum)).toString());
		}
	}			
}
//----------------------------------------------------------------


// class for creating ButtonBox
class BtnBoxChoice extends MultiChoice implements ActionListener
{
	int count;
	Panel p;
	Vector vb;
	Label lb;
	static int onFlag[];
	
	
	public BtnBoxChoice(MyFood choices)
	{
		super(choices);
		count = 0;
	}

	// create a ButtonBox containing several buttons
	public Panel getUI()
	{	
		p = new Panel();
		vb = new Vector(100, 10);
		onFlag = new int[10];
 
		p.setLayout(new GridLayout(choices.size()+1, 1));
		
		// add labeled button boxes to it
		for (int i=0; i< choices.size(); i++)
		{
			MyFood food = (MyFood) choices.get(i);
			String s = food.name;
			Button cb = new Button(s);
			cb.setBackground(Color.pink);
			cb.addActionListener(this);
			p.add(cb);
			
			vb.addElement(cb);
			count++;
		}

		lb = new Label();
		lb.setBackground(Color.green);
		p.add("South", lb);
		
		return p;
	}
	

	// event handler for clicking the button
	public void actionPerformed(ActionEvent evt)
	{
		Button bTmp;
		String sbTmp;	
	
		bTmp = (Button) evt.getSource();
		sbTmp = bTmp.getLabel();
		
		// set the color of the button according to the selected situation
		for(int i=0; i<choices.size(); i++)
		{
			MyFood food = (MyFood) choices.get(i);
			if(food.name==sbTmp)
			{
				if(onFlag[i]==0)
				{
					onFlag[i] = 1;
					bTmp.setBackground(Color.red);
					bTmp.setForeground(Color.red);
				}
				else if(onFlag[i]==1)
				{
					onFlag[i] = 0;
					bTmp.setBackground(Color.white);
				}
			}
		}
		
		// add money together for the selected items
		float sum = (float) 0.0;
		for(int i=0; i<choices.size(); i++)
		{
			if(onFlag[i]==1)
			{
				MyFood food = (MyFood) choices.get(i);
				sum = sum + food.price;
			}
		}
		lb.setText(("  " + new Float(sum)).toString());
	}
}
//----------------------------------------------------------------


// class for create the CheckBox
class CheckBoxChoice extends MultiChoice implements ItemListener
{
	int count;
	Panel p;
	Vector vcb;
	Label lbc;
	

	public CheckBoxChoice(MyFood choices)
	{
		super(choices);
		count = 0;
		p = new Panel();	
	}


	// create a CheckBox containing several CheckButtons with Label
	public Panel getUI()
	{	
		vcb = new Vector(100, 10);
		
		String s;
		p.setLayout(new GridLayout(choices.size()+1, 1));
		
		// add labeled check boxes
		for (int i=0; i< choices.size(); i++)
		{
			MyFood food = (MyFood) choices.get(i);
			s = food.name;
			Checkbox cb = new Checkbox(s);
			cb.addItemListener(this);
			p.add(cb);
			
			vcb.addElement(cb);
			
			count++;
		}

		lbc = new Label();
		lbc.setBackground(Color.green);
		p.add("South", lbc);
		return p;
	}


	// event handler for selecting the check box	
	public void itemStateChanged(ItemEvent ievt)
	{
		Checkbox cbTmp;
		
		if(ievt.getItemSelectable() instanceof Checkbox)
		{
			// add money togehter of slected items
			float sum = (float) 0.0;
			for (int i=0; i< choices.size(); i++)
			{
				
				cbTmp = (Checkbox) vcb.elementAt(i);
				
				if(cbTmp.getState())
				{
					MyFood food = (MyFood) choices.get(i);
					sum = sum + food.price;
				}		
			}
			lbc.setText(("  " + new Float(sum)).toString());
		}
	}			
}
//----------------------------------------------------------------


// class using Factory method to assign functions
class choiceFactory
{
	MultiChoice ui;
	
	// returns a Panel containing a set of choices 
	// displayed by one of several UI methods.
	public MultiChoice getChoiceUI(MyFood choices)
	{
		if(choices.size() <=3)
			ui = new CheckBoxChoice(choices);	// return a panel of checkboxes
		else if(choices.size()>=5)
			ui = new ListBoxChoice(choices);	// return a multi-select list box panel
		else
			ui = new BtnBoxChoice(choices);
			
		return ui;
	}
}
//----------------------------------------------------------------


// Main class for using GUI to calculate food cost
class CostBuilder extends Frame implements ActionListener, ItemListener
{
	MyFood MainFood, Fruit, Drink;
	List FoodList;
	Panel choicePanel;
	choiceFactory cfact;
	
	MyFood Bon, Bread, Noodle, Beef, Chicken, Fish;
	MyFood Apple, Grape, Peach, Pear;
	MyFood Wine, Juice, Milk;
	
	Panel p, pCalc;
	Button btnClose;
	Label lResult;
	
	
	public CostBuilder()
	{
		super("Food Cost Calculator");
		setGUI(); 
		buildFoodItems();	
		cfact = new choiceFactory();
		pack();	
	}	


	private void setGUI()
	{
		setLayout(new BorderLayout());
		p = new Panel();
		add("North", p);
		
		// frmae contains left and right panels
		p.setLayout(new GridLayout(1,2));
		//left is list of stocks
		FoodList= new List(10);
		p.add(FoodList);
		//right is empty at first
		choicePanel = new Panel();
		choicePanel.setBackground(Color.red);
		p.add(choicePanel);
		
		// bottom panel for dispalying the total money		
		pCalc = new Panel();
		pCalc.setLayout(new BorderLayout());
		pCalc.setBackground(Color.lightGray);
		add(pCalc);
		btnClose = new Button("Close");
		btnClose.addActionListener(this);
		pCalc.add("East", btnClose);
		lResult = new Label();
		lResult.setBackground(Color.green);
		pCalc.add(lResult);
		
		addWindowListener(new closeWin());
		
		setBounds(100, 100, 300, 200);
		setVisible(true);
	}
	
	
	public void buildFoodItems()
	{
		FoodList.add("MainFood");
		FoodList.add("Fruit");
		FoodList.add("Drink");
		FoodList.addItemListener(this);
		
		MainFood = new MyFood();
		Bon = new MyFood("Bon", (float) 4.0);
		Bread = new MyFood("Bread", (float) 6.2);
		Noodle = new MyFood("Noodle", (float) 3.5);
		Beef = new MyFood ("Beef", (float) 15.8);
		Chicken = new MyFood("Chicken", (float) 12.6);
		Fish = new MyFood("Fish", (float) 8.2);
		
		
		MainFood.addElement(Bon);
		MainFood.addElement(Bread);
		MainFood.addElement(Noodle);
		MainFood.addElement(Beef);
		MainFood.addElement(Chicken);
		MainFood.addElement(Fish);
		
		Fruit = new MyFood();
		Apple = new MyFood("Apple", (float) 5.8);
		Grape = new MyFood("Grape", (float) 3.2);
		Peach = new MyFood("Peach", (float) 2.8);
		Pear = new MyFood("Pear", (float) 4.6);
		Fruit.addElement(Apple);
		Fruit.addElement(Grape);
		Fruit.addElement(Peach);
		Fruit.addElement(Pear);
		
		Drink = new MyFood();
		Wine = new MyFood("Wine", (float) 12.5);
		Juice = new MyFood("Juice", (float) 6.8);
		Milk = new MyFood("Milk", (float) 5.0);
		Drink.addElement(Wine);
		Drink.addElement(Juice);
		Drink.addElement(Milk);
	}
	
	
	// event handler to close by clicking the close button
	public void actionPerformed(ActionEvent evt)
	{
		if(evt.getSource()==btnClose)
		{
			dispose();
			System.exit(0);
		}
	}
	
	
	// event handler to dispaly the sub-items on the right panel 
	// by clicking the food group name on the left panel
	public void itemStateChanged(ItemEvent ievt)
	{
		if(ievt.getSource()==FoodList)
		{
			MyFood v = null;
			int index = FoodList.getSelectedIndex();
							
			//this just switches among 3 different MyFoods
			//and passes the one you select to the Builder pattern	
			switch(index)
			{
			case 0:
				v = MainFood; 
				break;
				
			case 1:
				v = Fruit; 
				break;
				
			case 2:
				v = Drink;
				break;
			}
		
			MultiChoice mchoice = cfact.getChoiceUI(v);	// get one of the UIs

			choicePanel.removeAll(); 			// remove previous ui panel
			choicePanel.add(mchoice.getUI()); 	// insert in right panel
			choicePanel.validate(); 			// re-layout and display	
			
			// calculate the total money of a food goup
			float sum = (float) 0.0;
			for (int i=0; i<v.size(); i++)
			{
				MyFood food = (MyFood) v.get(i);
				sum = sum + food.price;
			}
			
			lResult.setText(("    " + new Float(sum)).toString());
				
		}			
	}
}
//----------------------------------------------------------------
	

// class for closing windows by clicking 'x' on the frame
class closeWin extends WindowAdapter
{
	public void winodowClose(WindowEvent evt)
	{
		Frame frm = (Frame) (evt.getSource());
		frm.dispose();
		System.exit(0);
	}
}
//----------------------------------------------------------------