{
计算器的功能实现
实现工厂设计模式
通过面向对象的思想，进行设计，所用的编程思想为对象的三大特性：封装，继承，多态
通过实现一个简单的 计算器的功能（输入两个数，进行加，减，乘，除）
思想思路：
1.设计虚拟父类;
2.子类继承父类
3. 通过虚拟方法，进行进行重载
4.工厂类，实例化对象，采用多态
}
unit uOperation;
interface
uses Classes, inifiles;
type
{基础类}
TOperation = class(Tobject)
private
FNumberA: Double;
FNumberB: Double;
public
function GetResult: double; virtual; abstract;
property NumberA: Double read FNumberA write FNumberA;
property NumberB: Double read FNumberB write FNumberB;
constructor create;
destructor Destroy; override;
end;
{加法}
TAdd = class(TOperation)
public
function GetResult: double; override;
end;
{减法}
TSub = class(Toperation)
public
function GetResult: double; override;
end;
{乘法}
TMultiple = class(TOperation)
public
function GetResult: double; override;
end;
{除法}
TDev = class(TOperation)
public
function GetResult: Double; override;
end;
{工厂类}
TOperationFactory = class
private
FOpMap: TStringHash;
public
{可以 GetOperation 定义为类方法，这样就不用创建TOperationFactory 对象，可以直接使用
TOperationFactory.GetOperation 但是在本例子中，由于要创建 FOpMap，所有不能定义 类方法，根据情况灵活应用，还有
简单工厂模式，返回值是父类型}
function GetOperation(Op: string): TOperation;
constructor create;
destructor Destroy; override;
end;
implementation
{ TOperation }
constructor TOperation.create;
begin
end;
destructor TOperation.Destroy;
begin
inherited;
end;
{ TAdd }
function TAdd.GetResult: double;
begin
result := FNumberA + FNumberB;
end;
{ TSub }
function TSub.GetResult: double;
begin
result := FNumberA - FNumberB;
end;
{ TMultiple }
function TMultiple.GetResult: double;
begin
Result := FNumberA * FNumberB;
end;
{ TDev }
function TDev.GetResult: Double;
begin
Result := 0;
if FNumberB <> 0 then
Result := FNumberA / FNumberB;
end;
{ TOperationFactory }
constructor TOperationFactory.create;
begin
FOpMap := TStringHash.Create;
FOpMap.Add('+', 1);
FOpMap.Add('-', 2);
FOpMap.Add('*', 3);
FOpMap.Add('/', 4);
end;
destructor TOperationFactory.Destroy;
begin
FOpMap.Free;
inherited;
end;
function TOperationFactory.GetOperation(Op: string): TOperation;
begin
result := nil;
case FOpMap.ValueOf(Op) of
1: result := TAdd.create;
2: result := TSub.create;
3: result := TMultiple.create;
4: result := TDev.create;
end;
end;
end.
{使用}
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
Edit2: TEdit;
Edit3: TEdit;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
Label4: TLabel;
Edit4: TEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
uses uOperation;
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
op: TOperation;
OpFact: TOperationFactory;
begin
OpFact := TOperationFactory.create;
op := OpFact.GetOperation(Edit4.Text);
try
if op = nil then exit;
op.NumberA := strtointdef(Edit1.Text, -1);
op.NumberB := strtointdef(Edit2.Text, -1);
edit3.Text := FloatToStr(op.GetResult);
finally
OPFact.Free;
OP.Free;
end;
end;
end.
窗体文件：
object Form1: TForm1
Left = 252
Top = 218
Width = 419
Height = 271
Caption = 'Form1'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object Label1: TLabel
Left = 120
Top = 56
Width = 60
Height = 13
Caption = '第一个数：'
end
object Label2: TLabel
Left = 120
Top = 88
Width = 60
Height = 13
Caption = '第二个数：'
end
object Label3: TLabel
Left = 120
Top = 144
Width = 36
Height = 13
Caption = '结果：'
end
object Label4: TLabel
Left = 120
Top = 114
Width = 48
Height = 13
Caption = '操作符：'
end
object Button1: TButton
Left = 232
Top = 176
Width = 75
Height = 25
Caption = '计算'
TabOrder = 0
OnClick = Button1Click
end
object Edit1: TEdit
Left = 184
Top = 56
Width = 121
Height = 21
TabOrder = 1
end
object Edit2: TEdit
Left = 184
Top = 88
Width = 121
Height = 21
TabOrder = 2
end
object Edit3: TEdit
Left = 184
Top = 144
Width = 121
Height = 21
TabOrder = 3
end
object Edit4: TEdit
Left = 184
Top = 114
Width = 121
Height = 21
TabOrder = 4
Text = '+'
end
end
// C Sharp 实现
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace OpeartionClass
{
//抽象父类
public class TOpeartion
{
private Double _NumberA = 0;
private double _NumberB = 0;
public Double NumberA
{
get { return _NumberA; }
set { _NumberA = value; }
}
public Double NumberB
{
get { return _NumberB; }
set { _NumberB = value; }
}
public virtual Double GetResult()
{
Double result = 0;
return result;
}
}
// 加法子类
public class TAdd : TOpeartion
{
public override Double GetResult()
{
Double result = 0;
result = NumberA + NumberB;
return result;
}
}
// 减法子类
public class TSub : TOpeartion
{
public override Double GetResult()
{
Double result = 0;
result = NumberA - NumberB;
return result;
}
}
// 乘法子类
public class TMul : TOpeartion
{
public override Double GetResult()
{
Double result = 0;
result = NumberA * NumberB;
return result;
}
}
// 除法子类
public class TDev : TOpeartion
{
public override double GetResult()
{
Double result = 0;
if (NumberB == 0)
throw new Exception("除数不能为零！");
result = NumberA / NumberB;
return result;
}
}
public class TFactoryCreate
{
public static TOpeartion GetOperation(string str)
{
TOpeartion opr = null;
switch (str)
{
case "+":
opr= new TAdd();
break;
case "-":
opr= new TSub();
break;
case "*":
opr = new TMul();
break;
case "/":
opr= new TDev();
break;
}
return opr;
}
}
}
// 调用
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using OpeartionClass;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
TOpeartion opr;
opr = TFactoryCreate.GetOperation(textBox3.Text);
opr.NumberA = Convert.ToInt32(textBox1.Text);
opr.NumberB = Convert.ToInt32(textBox2.Text);
textBox4.Text = Convert.ToString(opr.GetResult());
}
}
}
// 窗体文件
namespace WindowsFormsApplication1
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.button1 = new System.Windows.Forms.Button();
this.textBox1 = new System.Windows.Forms.TextBox();
this.textBox2 = new System.Windows.Forms.TextBox();
this.textBox3 = new System.Windows.Forms.TextBox();
this.textBox4 = new System.Windows.Forms.TextBox();
this.label1 = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
this.label3 = new System.Windows.Forms.Label();
this.label4 = new System.Windows.Forms.Label();
this.SuspendLayout();
//
// button1
//
this.button1.Location = new System.Drawing.Point(191, 168);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(64, 27);
this.button1.TabIndex = 0;
this.button1.Text = "计算";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(93, 23);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(120, 21);
this.textBox1.TabIndex = 1;
//
// textBox2
//
this.textBox2.Location = new System.Drawing.Point(93, 50);
this.textBox2.Name = "textBox2";
this.textBox2.Size = new System.Drawing.Size(120, 21);
this.textBox2.TabIndex = 2;
//
// textBox3
//
this.textBox3.Location = new System.Drawing.Point(93, 77);
this.textBox3.Name = "textBox3";
this.textBox3.Size = new System.Drawing.Size(120, 21);
this.textBox3.TabIndex = 3;
//
// textBox4
//
this.textBox4.Location = new System.Drawing.Point(93, 104);
this.textBox4.Name = "textBox4";
this.textBox4.Size = new System.Drawing.Size(120, 21);
this.textBox4.TabIndex = 4;
//
// label1
//
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(11, 26);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(77, 12);
this.label1.TabIndex = 5;
this.label1.Text = "第一个参数：";
//
// label2
//
this.label2.AutoSize = true;
this.label2.Location = new System.Drawing.Point(12, 50);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(77, 12);
this.label2.TabIndex = 6;
this.label2.Text = "第二个参数：";
//
// label3
//
this.label3.AutoSize = true;
this.label3.Location = new System.Drawing.Point(12, 80);
this.label3.Name = "label3";
this.label3.Size = new System.Drawing.Size(65, 12);
this.label3.TabIndex = 7;
this.label3.Text = "运算符号：";
//
// label4
//
this.label4.AutoSize = true;
this.label4.Location = new System.Drawing.Point(11, 113);
this.label4.Name = "label4";
this.label4.Size = new System.Drawing.Size(41, 12);
this.label4.TabIndex = 8;
this.label4.Text = "结果：";
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(296, 225);
this.Controls.Add(this.label4);
this.Controls.Add(this.label3);
this.Controls.Add(this.label2);
this.Controls.Add(this.label1);
this.Controls.Add(this.textBox4);
this.Controls.Add(this.textBox3);
this.Controls.Add(this.textBox2);
this.Controls.Add(this.textBox1);
this.Controls.Add(this.button1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.Button button1;
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.TextBox textBox2;
private System.Windows.Forms.TextBox textBox3;
private System.Windows.Forms.TextBox textBox4;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Label label2;
private System.Windows.Forms.Label label3;
private System.Windows.Forms.Label label4;
}
}
// JAVA 实现
//实现抽象类
package OperationFactory;
public abstract class Operation {
private double NumberA;
private double NumberB;
public double GetNumberA()
{
return NumberA;
}
public void SetNumberA(double numbera)
{
this.NumberA=numbera;
}
public double GetNumberB()
{
return NumberB;
}
public void SetNumberB(double numberb)
{
this.NumberB=numberb;
}
public abstract double getresult()throws Exception;
}
//实现子类 加法 OPerationAdd
package OperationFactory;
public class OperationAdd extends Operation {
@Override
public double getresult()throws Exception {
double result = 0;
result = GetNumberA() + GetNumberB();
return result;
}
}
//实现子类 除法 OperationDev
package OperationFactory;
public class OperationDev extends Operation {
@Override
public double getresult() throws Exception {
double result=0;
if (GetNumberB()==0)
throw new Exception("除数不能为0");
result=GetNumberA()/GetNumberB();
return result;
}
}
//实现子类 乘法 OPerationMul
package OperationFactory;
public class OperationMul extends Operation {
@Override
public double getresult() throws Exception {
// TODO Auto-generated method stub
double result=0;
result=GetNumberA() * GetNumberB();
return result;
}
}
//实现子类 减法 OperationSub
package OperationFactory;
public class OperationSub extends Operation {
@Override
public double getresult() throws Exception {
double result = 0;
result = GetNumberA() - GetNumberB();
return result;
}
}
// 工厂类 OperateFactory
package OperationFactory;
public class OperateFactory {
public static Operation CreateFactory(String sOperat){
Operation opr=null;
if ("+".equalsIgnoreCase(sOperat))
{
opr=new OperationAdd();
}else if ("-".equalsIgnoreCase(sOperat))
{
opr=new OperationSub();
}else if ("*".equalsIgnoreCase(sOperat))
{
opr=new OperationMul();
}else if ("/".equalsIgnoreCase(sOperat))
{
opr=new OperationDev();
}
return opr;
}
}
总结： 上面我用三种语言- Delphi 、C Sharp、 JAVA 实现了简单工厂设计模式。它们都是面向对象语言特性，都可以实现其模式设计。这样做的目的是一种尝试，对于初学者来，可以洞悉其中的异同，对于同时需要掌握多门开发语言的人来说，可以做一个比较，印象会更深刻。