工厂模式是一种快速创建大量对象的模式.简单易上手,今天我就谈一下我对工厂模式的理解.工厂模式的核心思想就是继承.子类继承父类的方法并且重写父类方法.下面我们就看一下实际中是如何使用工厂模式的.
现在我们需要创建一百个对象,其中五十个是学生对象,五十是老师对象.两者都继承与Person类.
现在我们需要在Person.h中声明一个创建方法.但是在Person.m中不做实现.
#import <Foundation/Foundation.h>
@interface Person : NSObject
@property(nonatomic,strong)NSString *name;
@end
然后我们需要在Student类中和Teacher类中对createNewObject方法进行方法的实现.当然了,Student类和Teacher类是继承于Person类的.
Student.中代码实现
#import "Person.h"
@interface Student : Person
@end
#import "Student.h"
@end
Teacher中代码实现如下
#import "Person.h"
@interface Teacher : Person
@end
#import "Teacher.h"
@implementation Teacher
@end
下面就需要创建批量生产的初始化工厂PersonFactory.
PersonFactory.h中
#import <Foundation/Foundation.h>
@class Teacher;
@class Student;
@interface PersonFactory : NSObject
//声明创建新对象的方法.
+(Student *)createNewStudent;
+(Teacher *)createNewTeacher;
@end
PersonFactory.m中
#import "PersonFactory.h"
#import "Student.h"
#import "Teacher.h"
@implementation PersonFactory
//实现创建新对象的方法.
+(Student *)createNewStudent{
Student *student = [[Student alloc]init];
student.name = @"栋哥";
return student;
}
+(Teacher *)createNewTeacher{
Teacher *teacher = [[Teacher alloc]init];
teacher.name = @"政哥";
return teacher;
}
@end
这里,我就使用ViewController调用一下createNewObject方法.然后我们就能批量生产带有特定name属性的学生对象和教师对象了.
#import "ViewController.h"
#import "Teacher.h"
#import "Student.h"
#import "PersonFactory.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
Teacher *teacher = [PersonFactory createNewTeacher];
NSLog(@"%@",teacher.name);
Student *student = [PersonFactory createNewStudent];
NSLog(@"%@",student.name);
}
@end
通过上面的方法,我们只能批量创建一些带有特殊属性的对象,如果现在我们需要把这些对象全部改变成另外的对象,我们改如何做呢? 这就需要我们再一步的细分我们的工厂.Person工厂中只做方法的声明,在Student工厂和Teacher中做出方法的实现.
PersonFactory.h中
#import <Foundation/Foundation.h>
@class Person;
@interface PersonFactory : NSObject
//只在.h中做方法的声明,在.m中不做方法的实现.
+(Person *)createNewObject;
@end
StudentFactory.m中
#import "StudentFactory.h"
#import "Student.h"
@implementation StudentFactory
+(Person *)createNewObject{
Student *student = [[Student alloc]init];
student.name = @"栋哥";
return student;
}
@end
同样.TeacherFactory.m中.
#import "TeacherFactory.h"
#import "Teacher.h"
@implementation TeacherFactory
+(Person *)createNewObject{
Teacher *teacher = [[Teacher alloc]init];
teacher.name = @"政哥";
return teacher;
}
@end
然后我们在ViewController中创建我们的两种对象.
#import "ViewController.h"
#import "Person.h"
#import "PersonFactory.h"
#import "StudentFactory.h"
#import "TeacherFactory.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
Person *teacher = [TeacherFactory createNewObject];
NSLog(@"%@",teacher.name);
Person *student = [StudentFactory createNewObject];
NSLog(@"%@",student.name);
}
@end
