设计模式之迭代器与访问者模式解析
迭代器模式
迭代器模式的代码片段展示了 Mark
协议和 Stroke
类的变化。以下是相关代码:
// Mark.h
@protocol Mark <NSObject>
@property (nonatomic, retain) UIColor *color;
@property (nonatomic, assign) CGFloat size;
@property (nonatomic, assign) CGPoint location;
@property (nonatomic, readonly) NSUInteger count;
@property (nonatomic, readonly) id <Mark> lastChild;
- (void) addMark:(id <Mark>) mark;
- (void) removeMark:(id <Mark>) mark;
- (id <Mark>) childMarkAtIndex:(NSUInteger) index;
- (NSEnumerator *) enumerator;
// for internal iterator implementation
- (void) enumerateMarksUsingBlock:(void (^)(id <Mark> item, BOOL *stop)) block;
@end
Stroke