設計模式-建造者模式 C++實現

建造者模式

定義：將一個複雜對象的構造與他的表示分離，是同樣的構造過程可以創建不同的表示。可以想象爲先創建一個產品的骨架，再拼接他的零件。

特點：（1）各個具體的建造者相互獨立，有利於系統的擴展。（2）客戶端不必知道產品內部的組成細節，便於控制細節風險。

主要角色 Product,AbstractBuilder,Builder,Director

C++實現

Product.h

#pragma once
#include<string>
using namespace std;
class Product {
public:
	Product();
	~Product();
	void setPartA(string param);
	void setPartB(string param);
	void setPartC(string param);
	void show();
private:
	string partA;
	string partB;
	string partC;
};

Product.cpp

#include"Product.h"
#include<iostream>

using namespace std;

Product::Product() {

}
Product::~Product() {

}
void Product::setPartA(string param) {
	this->partA = param;
}
void Product::setPartB(string param) {
	this->partB = param;
}
void Product::setPartC(string param) {
	this->partC = param;
}
void Product::show() {
	cout << "partA:" << partA << " partB:" << partB << " partC:" << partC << endl;
}

Builder.h

#pragma once
#include"Product.h"
class AbstractBuilder {
public:
	AbstractBuilder();
	virtual ~AbstractBuilder();
	virtual void buildPartA(string param) = 0;
	virtual void buildPartB(string param) = 0;
	virtual void buildPartC(string param) = 0;
	virtual void PrepareProduct() = 0;
	virtual Product* createProduct() = 0;
};
class Builder :public AbstractBuilder {
public:
	Builder();
	~Builder();
	void buildPartA(string param);
	void buildPartB(string param);
	void buildPartC(string param);
	void PrepareProduct();
	Product* createProduct();
private:
	Product* curProduct;
};

Builder.cpp

#include"Builder.h"
#include<iostream>

using namespace std;
AbstractBuilder::AbstractBuilder() {

}
AbstractBuilder::~AbstractBuilder() {

}
Builder::Builder() {

}
Builder::~Builder() {

}
void Builder::PrepareProduct() {
	cout << "創建一個產品骨架" << endl;
	curProduct = new Product();

}
void Builder::buildPartA(string param) {
	cout << "正在構造產品A部分" << endl;
	curProduct->setPartA(param);
}
void Builder::buildPartB(string param) {
	cout << "正在構建產品B部分" << endl;
	curProduct->setPartB(param);
}
void Builder::buildPartC(string param) {
	cout << "正在構建產品C部分" << endl;
	curProduct->setPartC(param);
}
Product* Builder::createProduct() {
	return curProduct;
}

Director.h

#pragma once
#include"Builder.h"
class Director {
public:
	Director(AbstractBuilder* builder);
	~Director();
	void construct();
private:
	AbstractBuilder* curBuilder;
};

Director.cpp

#include"Director.h"
Director::Director(AbstractBuilder* builder) {
	this->curBuilder = builder;
}
Director::~Director() {

}
void Director::construct() {
	if (curBuilder == nullptr)	return;
	curBuilder->PrepareProduct();
	curBuilder->buildPartA("A");
	curBuilder->buildPartB("B");
	curBuilder->buildPartC("C");
}

main.cpp

#include"Director.h"
int main(void) {
	AbstractBuilder* builder = new Builder();
	Director* director = new Director(builder);

	director->construct();
	Product* product = builder->createProduct();
	product->show();
	return 0;
}