ParamGenerator

ParamBuilder.h

//
//  ParamBuilder.h
//  Petbox
//
//  Created by Алексей Демедецкий on 02.03.12.
//  Copyright (c) 2012 Ciklum. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface ParamBuilder : NSObject

- (NSDictionary*)buildDictionary;

@end

ParamBuilder.m

//
//  ParamBuilder.m
//  Petbox
//
//  Created by Алексей Демедецкий on 02.03.12.
//  Copyright (c) 2012 Ciklum. All rights reserved.
//

#import "ParamBuilder.h"

@interface ParamBuilder()

@property (nonatomic, readonly) NSMutableDictionary* dict;

@end


static NSString *PropertyNameFromSetter(NSString *setterName)
{
    setterName = [setterName substringFromIndex:3];                // Remove "set"
    NSString *firstChar = [[setterName substringToIndex:1] lowercaseString];
    NSString *tail = [setterName substringFromIndex:1];
    tail = [tail substringToIndex:[tail length] - 1];        // Remove ":"
    return [firstChar stringByAppendingString:tail];        // Convert first char to lowercase.
}


static id DynamicDictionaryGetter(id self, SEL _cmd)
{
    ParamBuilder* _self = self;
    return [_self.dict objectForKey:NSStringFromSelector(_cmd)];
}


static void DynamicDictionarySetter(id self, SEL _cmd, id value)
{
    ParamBuilder* _self = self;
    NSString *key = PropertyNameFromSetter(NSStringFromSelector(_cmd));
    
    if (value == nil)
    {
        [_self.dict removeObjectForKey:key];
    }
    else
    {
        [_self.dict setObject:value forKey:key];
    }
}

@implementation ParamBuilder

objection_register(ParamBuilder);

@synthesize dict = _dict;

- (id)init
{
    self = [super init];
    if (self) {
        _dict = [NSMutableDictionary dictionary];
    }
    return self;
}

- (NSDictionary *)buildDictionary
{
    return [self.dict copy];
}

+ (BOOL)resolveInstanceMethod:(SEL)sel
{
    NSString *selStr = NSStringFromSelector(sel);
    // Only handle selectors beginning with "set", ending with a colon and with no intermediate colons.
    // Also, to simplify PropertyNameFromSetter, we requre a length of at least 5 (2 + "set").
    if ([selStr rangeOfString:@":"].location == NSNotFound)
    {
        DLog(@"Generating dynamic accessor -%@", selStr);
        return class_addMethod(self, sel, (IMP)DynamicDictionaryGetter, @encode(id(*)(id, SEL)));
    }
    if ([selStr hasPrefix:@"set"] &&
        [selStr hasSuffix:@":"] &&
        [selStr rangeOfString:@":" options:0 range:NSMakeRange(0, [selStr length] - 1)].location == NSNotFound &&
        [selStr length] >= 6)
    {
        DLog(@"Generating dynamic accessor -%@ for property \"%@\"", 
             selStr, PropertyNameFromSetter(selStr));
        return class_addMethod(self, sel, (IMP)DynamicDictionarySetter, @encode(id(*)(id, SEL, id)));
    }
    else
    {
        return [super resolveInstanceMethod:sel];
    }
}

@end