设计模式(1)-模板模式(Template) (一)

【描述】模板设计模式将常用的方法进行封装，创建了一个实施一组方法和功能的抽象的对象。子类通常将这个对象作为模板用于设计。

【UML图】
图1 UML图

1 DrawTemplate有三个抽象的方法：draw() - (protected)、getMethod() - (public)、setMethod() - (protected、纯虚函数-接口)

2 Draw1和Draw2继承了DrawTemplate，Draw1对draw()方法进行了重载、重用了DrawTemplate类的getMethod()方法，实现了setMethod接口。Draw2对draw()、getMethod()方法进行了重载，实现了setMethod接口。

3 对方法的重用是模板模式的优点，如Draw1重用了DrawTemplate类的getMethod方法

【示例代码】

drawtemplate.h

[html] view plaincopyprint #ifndef DRAWTEMPLATE_H
#define DRAWTEMPLATE_H

#include
class DrawTemplate
{
public:
DrawTemplate();

protected:
virtual void draw();
virtual void setMethod(QString method) const = 0;

public:
virtual QString getMethod();
};

#endif // DRAWTEMPLATE_H
#ifndef DRAWTEMPLATE_H
#define DRAWTEMPLATE_H

#include
class DrawTemplate
{
public:
DrawTemplate();

protected:
virtual void draw();
virtual void setMethod(QString method) const = 0;

public:
virtual QString getMethod();
};

#endif // DRAWTEMPLATE_H

drawtemplate.cpp

[html] view plaincopyprint #include
#include "drawtemplate.h"

DrawTemplate::DrawTemplate()
{
qDebug()<<"construct DrawTemplate";
}

void DrawTemplate::draw()
{
qDebug()<<"DrawTemplate::draw()";
setMethod(getMethod());
}

QString DrawTemplate::getMethod()
{
QString test = "Method::DrawTemplate";
qDebug()<<"DrawTemplate::getMethod()";
return test;
}
#include
#include "drawtemplate.h"

DrawTemplate::DrawTemplate()
{
qDebug()<<"construct DrawTemplate";
}

void DrawTemplate::draw()
{
qDebug()<<"DrawTemplate::draw()";
setMethod(getMethod());
}

QString DrawTemplate::getMethod()
{
QString test = "Method::DrawTemplate";
qDebug()<<"DrawTemplate::getMethod()";
return test;
}

draw1.h

[html] view plaincopyprint #ifndef DRAW1_H
#define DRAW1_H

#include "drawtemplate.h"

class Draw1 : public DrawTemplate
{
public:
Draw1();

public:
void draw();

void setMethod(QString) const;
};

#endif // DRAW1_H
#ifndef DRAW1_H
#define DRAW1_H

#include "drawtemplate.h"

class Draw1 : public DrawTemplate
{
public:
Draw1();

public:
void draw();

void setMethod(QString) const;
};

#endif // DRAW1_H

draw1.cpp

[html] view plaincopyprint #include
#include "draw1.h"

Draw1::Draw1()
{
qDebug()<<"construct Draw1";
}

void Draw1::draw()
{
qDebug()<<"Draw1::draw()";
setMethod(getMethod());
}

void Draw1::setMethod(QString method) const
{
qDebug()< }
#include
#include "draw1.h"

Draw1::Draw1()
{
qDebug()<<"construct Draw1";
}

void Draw1::draw()
{
qDebug()<<"Draw1::draw()";
setMethod(getMethod());
}

void Draw1::setMethod(QString method) const
{
qDebug()< }

draw2.h

[html] view plaincopyprint #ifndef DRAW2_H
#define DRAW2_H

#include "drawtemplate.h"

class Draw2 : public DrawTemplate
{
public:
Draw2();

public:
void draw();

QString getMethod();
void setMethod(QString method) const;
};

#endif // DRAW2_H
#ifndef DRAW2_H
#define DRAW2_H

#include "drawtemplate.h"

class Draw2 : public DrawTemplate
{
public:
Draw2();

public:
void draw();

QString getMethod();
void setMethod(QString method) const;
};

#endif // DRAW2_H

draw2.cpp

[html] view plaincopyprint #include
#include "draw2.h"

Draw2::Draw2()
{
qDebug()<<"construct Draw2";
}

void Draw2::draw()
{
qDebug()<<"Draw2::draw()";
setMethod(getMethod());
}

QString Draw2::getMethod()
{
QString test = "Method::Draw2";
qDebug()<<"Draw2::getMethod()";
return test;
}

void Draw2::setMethod(QString method) const
{
qDebug()< }
#include
#include "draw2.h"

Draw2::Draw2()
{
qD