05. 建造者模式

建造者模式：建造过程相同，然后可以建造出不同的产品。简单工厂模式是同一个工厂生产不同的产品。侧重点有些区别。代码示例如下

/**
 * @file builder.h
 * @brief builder pattern
 * @author timeshark
 * @version 1.0
 * @date 2018-08-07
 */

#ifndef BUILDER_H
#define BUILDER_H

#include <iostream>

using std::cout;
using std::endl;

class Builder {
public:
    virtual void build_head() = 0;
    virtual void build_body() = 0;
    virtual void build_left_arm() = 0;
    virtual void build_right_arm() = 0;
    virtual void build_left_leg() = 0;
    virtual void build_right_leg() = 0;
};

class ThinBuilder : public Builder {
public:
    void build_head() { cout << "build thin head" << endl; }
    void build_body() { cout << "build thin body" << endl; }
    void build_left_arm() { cout << "build thin left arm" << endl; }
    void build_right_arm() { cout << "build thin right arm" << endl; }
    void build_left_leg() { cout << "build thin left leg" << endl; }
    void build_right_leg() { cout << "build thin right leg" << endl; }
};

class FatBuilder : public Builder {
public:
    void build_head() { cout << "build fat head" << endl; }
    void build_body() { cout << "build fat body" << endl; }
    void build_left_arm() { cout << "build fat left arm" << endl; }
    void build_right_arm() { cout << "build fat right arm" << endl; }
    void build_left_leg() { cout << "build fat left leg" << endl; }
    void build_right_leg() { cout << "build fat right leg" << endl; }
};

class Director {
public:
    Director(Builder *builder) : _builder(builder) {}

    ~Director() {
        // 注意存在内存泄露问题
        _builder = NULL;
    }

    void create() {
        _builder->build_head();
        _builder->build_body();
        _builder->build_left_arm();
        _builder->build_right_arm();
        _builder->build_left_leg();
        _builder->build_right_leg();
    }

private:
    Builder* _builder;
};

#endif

/**
 * @file main.cpp
 * @brief main
 * @author timeshark
 * @version 1.0
 * @date 2018-08-07
 */

#include "builder.h"

int main() {
    ThinBuilder thin;
    FatBuilder fat;

    Director director(&thin);
    director.create();

    Director director2(&fat);
    director2.create();

    return 0;
}

输出：

猜你喜欢