fix(nullattributes): Accepting null attributes and eventTags (#335)

* null support for attributes & eventTags Notification Center PR.

* Nullable attribute and eventTags activate listener and track listener

* Generic listener and sendNotifications should have NSDictionary.

* Addressed Code Review comments.

* Minor conflicts resolved.

* Addressed code review comments.

* adding xcpretty

* Notification Center issues fixed.

* removed xcpretty

* supress warnings.

Author: msohailhussain

.travis.yml

@@ -15,7 +15,7 @@ before_install:
   - gem install slather --no-rdoc --no-ri --no-document --quiet
 script:
   - pod spec lint --quick
-  - if [[ "$TRAVIS_BRANCH" == "master" ]]; then xcodebuild test -quiet -workspace OptimizelySDK.xcworkspace -scheme $SCHEME -configuration Release CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO -sdk $TEST_SDK -destination "platform=$PLATFORM,OS=$OS,name=$NAME" ONLY_ACTIVE_ARCH=YES | egrep -B 10 -A 10 "(error|warning|failed|crash|exit|FAILED|Failing|failures)"; fi
+  - if [[ "$TRAVIS_BRANCH" == "master" ]]; then xcodebuild test -quiet -workspace OptimizelySDK.xcworkspace -scheme $SCHEME -configuration Release CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO -sdk $TEST_SDK -destination "platform=$PLATFORM,OS=$OS,name=$NAME" ONLY_ACTIVE_ARCH=YES | egrep -B 10 -A 10 "(error|failed|crash|exit|FAILED|Failing|failures)"; fi
 after_success:
   - slather
   - sleep 5 # https://github.com/travis-ci/travis-ci/issues/4725

OptimizelySDKCore/OptimizelySDKCore.xcodeproj/project.pbxproj

@@ -225,6 +225,10 @@
 		90855D0120ED254600A97BEC /* OPTLYControlAttributes.h in Headers */ = {isa = PBXBuildFile; fileRef = 90855CFC20ED237F00A97BEC /* OPTLYControlAttributes.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		90855D0D20ED2E0100A97BEC /* OPTLYControlAttributes.m in Sources */ = {isa = PBXBuildFile; fileRef = 90855D0420ED2B0200A97BEC /* OPTLYControlAttributes.m */; };
 		90855D0E20ED2E0300A97BEC /* OPTLYControlAttributes.m in Sources */ = {isa = PBXBuildFile; fileRef = 90855D0420ED2B0200A97BEC /* OPTLYControlAttributes.m */; };
+		C77958C3219BFBC300B4CA89 /* OPTLYNSObject+Validation.h in Headers */ = {isa = PBXBuildFile; fileRef = C77958C0219BFBA000B4CA89 /* OPTLYNSObject+Validation.h */; };
+		C77958C4219BFBC400B4CA89 /* OPTLYNSObject+Validation.h in Headers */ = {isa = PBXBuildFile; fileRef = C77958C0219BFBA000B4CA89 /* OPTLYNSObject+Validation.h */; };
+		C77958C5219BFBC700B4CA89 /* OPTLYNSObject+Validation.m in Sources */ = {isa = PBXBuildFile; fileRef = C77958C1219BFBA000B4CA89 /* OPTLYNSObject+Validation.m */; };
+		C77958C6219BFBC800B4CA89 /* OPTLYNSObject+Validation.m in Sources */ = {isa = PBXBuildFile; fileRef = C77958C1219BFBA000B4CA89 /* OPTLYNSObject+Validation.m */; };
 		EA064BC71DD3FC8800DF7537 /* OPTLYQueue.h in Headers */ = {isa = PBXBuildFile; fileRef = EA064BC51DD3FC8800DF7537 /* OPTLYQueue.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		EA064BC81DD3FC8800DF7537 /* OPTLYQueue.h in Headers */ = {isa = PBXBuildFile; fileRef = EA064BC51DD3FC8800DF7537 /* OPTLYQueue.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		EA064BC91DD3FC8800DF7537 /* OPTLYQueue.m in Sources */ = {isa = PBXBuildFile; fileRef = EA064BC61DD3FC8800DF7537 /* OPTLYQueue.m */; };
@@ -629,6 +633,8 @@
 		A52039FD7B704890859320C4 /* Pods-OptimizelySDKCoreiOSTests.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-OptimizelySDKCoreiOSTests.debug.xcconfig"; path = "../Pods/Target Support Files/Pods-OptimizelySDKCoreiOSTests/Pods-OptimizelySDKCoreiOSTests.debug.xcconfig"; sourceTree = "<group>"; };
 		B333468714C0D4A8633103EF /* Pods-OptimizelySDKCoreiOSTests.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-OptimizelySDKCoreiOSTests.release.xcconfig"; path = "../Pods/Target Support Files/Pods-OptimizelySDKCoreiOSTests/Pods-OptimizelySDKCoreiOSTests.release.xcconfig"; sourceTree = "<group>"; };
 		BE0C3BD9DC6186DB98A667C2 /* Pods_OptimizelySDKCoreTVOS.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_OptimizelySDKCoreTVOS.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		C77958C0219BFBA000B4CA89 /* OPTLYNSObject+Validation.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "OPTLYNSObject+Validation.h"; sourceTree = "<group>"; };
+		C77958C1219BFBA000B4CA89 /* OPTLYNSObject+Validation.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "OPTLYNSObject+Validation.m"; sourceTree = "<group>"; };
 		E2E7211C032DF7A75264FDDB /* Pods-OptimizelySDKCoreTVOSTests.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-OptimizelySDKCoreTVOSTests.debug.xcconfig"; path = "../Pods/Target Support Files/Pods-OptimizelySDKCoreTVOSTests/Pods-OptimizelySDKCoreTVOSTests.debug.xcconfig"; sourceTree = "<group>"; };
 		EA064BC51DD3FC8800DF7537 /* OPTLYQueue.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OPTLYQueue.h; sourceTree = "<group>"; };
 		EA064BC61DD3FC8800DF7537 /* OPTLYQueue.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OPTLYQueue.m; sourceTree = "<group>"; };
@@ -1003,6 +1009,15 @@
 			name = Pods;
 			sourceTree = "<group>";
 		};
+		C77958BF219BFADE00B4CA89 /* Categories */ = {
+			isa = PBXGroup;
+			children = (
+				C77958C0219BFBA000B4CA89 /* OPTLYNSObject+Validation.h */,
+				C77958C1219BFBA000B4CA89 /* OPTLYNSObject+Validation.m */,
+			);
+			name = Categories;
+			sourceTree = "<group>";
+		};
 		EA2FA83D1DC5E0E900B1D81B /* Utilities */ = {
 			isa = PBXGroup;
 			children = (
@@ -1216,6 +1231,7 @@
 				EA2FAA4A1DC6F53E00B1D81B /* Optimizely.m */,
 				EA2FA83F1DC5E11F00B1D81B /* Bucketer */,
 				EA2FA90B1DC6F17400B1D81B /* Builder */,
+				C77958BF219BFADE00B4CA89 /* Categories */,
 				EA2FA8401DC5E13A00B1D81B /* Data Models */,
 				EA2FA8411DC5E14700B1D81B /* Error Handler */,
 				EA2FA8421DC5E15700B1D81B /* Event Builder */,
@@ -1348,6 +1364,7 @@
 				EA2FAAAC1DC6F57200B1D81B /* OPTLYEvent.h in Headers */,
 				EA2FAAD01DC6F57200B1D81B /* OPTLYEventFeature.h in Headers */,
 				EA2C24331DE7887C0063ADA0 /* OPTLYVariationVariable.h in Headers */,
+				C77958C3219BFBC300B4CA89 /* OPTLYNSObject+Validation.h in Headers */,
 				EA2FAABE1DC6F57200B1D81B /* OPTLYEventDecision.h in Headers */,
 				EA2FAAA61DC6F57200B1D81B /* OPTLYDecisionEventTicket.h in Headers */,
 				EA2FAAC41DC6F57200B1D81B /* OPTLYEventDecisionTicket.h in Headers */,
@@ -1413,6 +1430,7 @@
 				EA2FAAE91DC6F57200B1D81B /* OPTLYEventParameterKeys.h in Headers */,
 				EA2FAAFB1DC6F57200B1D81B /* OPTLYEventView.h in Headers */,
 				EA2C24341DE7887C0063ADA0 /* OPTLYVariationVariable.h in Headers */,
+				C77958C4219BFBC400B4CA89 /* OPTLYNSObject+Validation.h in Headers */,
 				EA2FAABF1DC6F57200B1D81B /* OPTLYEventDecision.h in Headers */,
 				EA2FAAD71DC6F57200B1D81B /* OPTLYEventHeader.h in Headers */,
 				EA2FAAD11DC6F57200B1D81B /* OPTLYEventFeature.h in Headers */,
@@ -1914,6 +1932,7 @@
 				EA2FAC0A1DC6FFC600B1D81B /* OPTLYAttribute.m in Sources */,
 				EA2FAC0B1DC6FFC600B1D81B /* OPTLYAudience.m in Sources */,
 				EA2FAC0C1DC6FFC600B1D81B /* OPTLYBaseCondition.m in Sources */,
+				C77958C5219BFBC700B4CA89 /* OPTLYNSObject+Validation.m in Sources */,
 				EA2FAC0D1DC6FFC600B1D81B /* OPTLYCondition.m in Sources */,
 				EA2FAC0E1DC6FFC600B1D81B /* OPTLYDatafileKeys.m in Sources */,
 				EA2FAC0F1DC6FFC600B1D81B /* OPTLYDecisionEventTicket.m in Sources */,
@@ -2005,6 +2024,7 @@
 				EA2FABE61DC6FFA100B1D81B /* OPTLYAudience.m in Sources */,
 				EA2FABE71DC6FFA100B1D81B /* OPTLYBaseCondition.m in Sources */,
 				EA2FABE81DC6FFA100B1D81B /* OPTLYCondition.m in Sources */,
+				C77958C6219BFBC800B4CA89 /* OPTLYNSObject+Validation.m in Sources */,
 				EA2FABE91DC6FFA100B1D81B /* OPTLYDatafileKeys.m in Sources */,
 				EA2FABEA1DC6FFA100B1D81B /* OPTLYDecisionEventTicket.m in Sources */,
 				EA2FABEB1DC6FFA100B1D81B /* OPTLYEvent.m in Sources */,

OptimizelySDKCore/OptimizelySDKCore/OPTLYDecisionService.m

@@ -31,6 +31,7 @@
 #import "OPTLYFeatureDecision.h"
 #import "OPTLYGroup.h"
 #import "OPTLYControlAttributes.h"
+#import "OPTLYNSObject+Validation.h"
 
 @interface OPTLYDecisionService()
 @property (nonatomic, strong) OPTLYProjectConfig *config;
@@ -163,11 +164,14 @@ - (NSString *)getBucketingId:(NSString *)userId
     NSString *bucketingId = userId;
     // If the bucketing ID key is defined in attributes, then use that
     // in place of the userID for the murmur hash key
-    if (![OPTLYDecisionService isEmptyString:attributes[OptimizelyBucketId]]) {
-        bucketingId = attributes[OptimizelyBucketId];
-        [self.config.logger logMessage:[NSString stringWithFormat:OPTLYLoggerMessagesDecisionServiceSettingTheBucketingID,
-                                        bucketingId]
-                             withLevel:OptimizelyLogLevelDebug];
+    if (attributes != nil) {
+        NSString *validBucketingId = [attributes[OptimizelyBucketId] getValidString];
+        if (validBucketingId != nil) {
+            bucketingId = validBucketingId;
+            [self.config.logger logMessage:[NSString stringWithFormat:OPTLYLoggerMessagesDecisionServiceSettingTheBucketingID,
+                                            bucketingId]
+                                 withLevel:OptimizelyLogLevelDebug];
+        }
     }
     return bucketingId;
 }
@@ -194,7 +198,7 @@ - (OPTLYFeatureDecision *)getVariationForFeatureGroup:(OPTLYFeatureFlag *)featur
     OPTLYFeatureDecision *decision = nil;
     NSString *logMessage = nil;
 
-    if ([OPTLYDecisionService isEmptyString:groupId]) {
+    if ([groupId getValidString] == nil) {
         logMessage = OPTLYLoggerMessagesDecisionServiceGroupIdNotFound;
     } else {
         NSString *bucketing_id = [self getBucketingId:userId attributes:attributes];
@@ -230,7 +234,7 @@ - (OPTLYFeatureDecision *)getVariationForFeatureExperiment:(OPTLYFeatureFlag *)f
     NSString *featureFlagKey = featureFlag.key;
     NSArray *experimentIds = featureFlag.experimentIds;
     // Check if there are any experiment IDs inside feature flag
-    if ([OPTLYDecisionService isEmptyArray:experimentIds]) {
+    if ([experimentIds getValidArray] == nil) {
         [self.config.logger logMessage:[NSString stringWithFormat:OPTLYLoggerMessagesDecisionServiceFFNotUsed, featureFlagKey]
                              withLevel:OptimizelyLogLevelDebug];
         return nil;
@@ -266,7 +270,7 @@ - (OPTLYFeatureDecision *)getVariationForFeatureRollout:(OPTLYFeatureFlag *)feat
     NSString *bucketing_id = [self getBucketingId:userId attributes:attributes];
     NSString *featureFlagKey = featureFlag.key;
     NSString *rolloutId = featureFlag.rolloutId;
-    if ([OPTLYDecisionService isEmptyString:rolloutId]) {
+    if ([rolloutId getValidString] == nil) {
         [self.config.logger logMessage:[NSString stringWithFormat:OPTLYLoggerMessagesDecisionServiceFFNotUsed, featureFlagKey]
                              withLevel:OptimizelyLogLevelDebug];
         return nil;
@@ -277,7 +281,7 @@ - (OPTLYFeatureDecision *)getVariationForFeatureRollout:(OPTLYFeatureFlag *)feat
         return nil;
     }
     NSArray *rolloutRules = rollout.experiments;
-    if ([OPTLYDecisionService isEmptyArray:rolloutRules]) {
+    if ([rolloutRules getValidArray] == nil) {
         return nil;
     }
     // Evaluate all rollout rules except for last one
@@ -500,17 +504,4 @@ - (BOOL)isUserInExperiment:(OPTLYProjectConfig *)config
 
     return false;
 }
-
-+ (BOOL)isEmptyString:(NSObject*)string {
-    return (!string
-            || ![string isKindOfClass:[NSString class]]
-            || [(NSString *)string isEqualToString:@""]);
-}
-
-
-+ (BOOL)isEmptyArray:(NSObject*)array {
-    return (!array
-            || ![array isKindOfClass:[NSArray class]]
-            || (((NSArray *)array).count == 0));
-}
 @end

OptimizelySDKCore/OptimizelySDKCore/OPTLYEventBuilder.m

@@ -25,6 +25,7 @@
 #import "OPTLYLogger.h"
 #import "OPTLYProjectConfig.h"
 #import "OPTLYVariation.h"
+#import "OPTLYNSObject+Validation.h"
 
 NSString * const OptimizelyActivateEventKey = @"campaign_activated";
 
@@ -92,15 +93,15 @@ - (NSDictionary *)createCommonParamsForUser:(NSString *)userId
 
     NSMutableDictionary *visitor = [NSMutableDictionary new];
     visitor[OPTLYEventParameterKeysSnapshots] =  [NSMutableArray new];
-    visitor[OPTLYEventParameterKeysVisitorId] = [OPTLYEventBuilderDefault stringOrEmpty:userId];
+    visitor[OPTLYEventParameterKeysVisitorId] = [userId getStringOrEmpty];
     visitor[OPTLYEventParameterKeysAttributes] = [self createUserFeatures:self.config attributes:attributes];
 
     commonParams[OPTLYEventParameterKeysVisitors] = @[visitor];
-    commonParams[OPTLYEventParameterKeysProjectId] = [OPTLYEventBuilderDefault stringOrEmpty:self.config.projectId ];
-    commonParams[OPTLYEventParameterKeysAccountId] = [OPTLYEventBuilderDefault stringOrEmpty:self.config.accountId];
-    commonParams[OPTLYEventParameterKeysClientEngine] = [OPTLYEventBuilderDefault stringOrEmpty:[self.config clientEngine]];
-    commonParams[OPTLYEventParameterKeysClientVersion] = [OPTLYEventBuilderDefault stringOrEmpty:[self.config clientVersion]];
-    commonParams[OPTLYEventParameterKeysRevision] = [OPTLYEventBuilderDefault stringOrEmpty:self.config.revision];
+    commonParams[OPTLYEventParameterKeysProjectId] = [self.config.projectId getStringOrEmpty];
+    commonParams[OPTLYEventParameterKeysAccountId] = [self.config.accountId getStringOrEmpty];
+    commonParams[OPTLYEventParameterKeysClientEngine] = [[self.config clientEngine] getStringOrEmpty];
+    commonParams[OPTLYEventParameterKeysClientVersion] = [[self.config clientVersion] getStringOrEmpty];
+    commonParams[OPTLYEventParameterKeysRevision] = [self.config.revision getStringOrEmpty];
     commonParams[OPTLYEventParameterKeysAnonymizeIP] = @(self.config.anonymizeIP.boolValue);
 
     return [commonParams copy];
@@ -111,13 +112,13 @@ - (NSDictionary *)createImpressionParamsOfExperiment:(OPTLYExperiment *)experime
     NSMutableDictionary *snapshot = [NSMutableDictionary new];
 
     NSMutableDictionary *decision = [NSMutableDictionary new];
-    decision[OPTLYEventParameterKeysDecisionCampaignId]     = [OPTLYEventBuilderDefault stringOrEmpty:experiment.layerId];
+    decision[OPTLYEventParameterKeysDecisionCampaignId]     = [experiment.layerId getStringOrEmpty];
     decision[OPTLYEventParameterKeysDecisionExperimentId]   = experiment.experimentId;
     decision[OPTLYEventParameterKeysDecisionVariationId]    = variation.variationId;
     NSArray *decisions = @[decision];
 
     NSMutableDictionary *event = [NSMutableDictionary new];
-    event[OPTLYEventParameterKeysEntityId]      = [OPTLYEventBuilderDefault stringOrEmpty:experiment.layerId];
+    event[OPTLYEventParameterKeysEntityId]      = [experiment.layerId getStringOrEmpty];
     event[OPTLYEventParameterKeysTimestamp]     = [self time] ? : @0;
     event[OPTLYEventParameterKeysKey]           = OptimizelyActivateEventKey;
     event[OPTLYEventParameterKeysUUID]          = [[NSUUID UUID] UUIDString];
@@ -149,7 +150,7 @@ - (NSArray *)createConversionParamsOfEvent:(OPTLYEvent *)event
     NSMutableDictionary *snapshot = [NSMutableDictionary new];
 
     NSMutableDictionary *eventDict = [NSMutableDictionary new];
-    eventDict[OPTLYEventParameterKeysEntityId]      = [OPTLYEventBuilderDefault stringOrEmpty:event.eventId];
+    eventDict[OPTLYEventParameterKeysEntityId]      = [event.eventId getStringOrEmpty];
     eventDict[OPTLYEventParameterKeysTimestamp]     = [self time] ? : @0;
     eventDict[OPTLYEventParameterKeysKey]           = event.eventKey;
     eventDict[OPTLYEventParameterKeysUUID]          = [[NSUUID UUID] UUIDString];
@@ -213,7 +214,7 @@ - (NSArray *)createUserFeatures:(OPTLYProjectConfig *)config
             continue;
         }
         NSString *attributeId = [config getAttributeIdForKey:attributeKey];
-        if ([OPTLYEventBuilderDefault isEmptyString:attributeId]) {
+        if ([attributeId getValidString] == nil) {
             NSString *logMessage = [NSString stringWithFormat:OPTLYLoggerMessagesAttributeInvalidFormat, attributeKey];
             [config.logger logMessage:logMessage withLevel:OptimizelyLogLevelDebug];
             continue;
@@ -247,17 +248,6 @@ - (NSNumber *)time
     return timestamp;
 }
 
-+ (NSString *)stringOrEmpty:(NSString *)str {
-    NSString *string = str != nil ? str : @"";
-    return string;
-}
-
-+ (BOOL)isEmptyString:(NSObject *)str {
-    return (!str
-            || ![str isKindOfClass:[NSString class]]
-            || [(NSString *)str isEqualToString:@""]);
-}
-
 + (BOOL)isValidAttributeValue:(NSObject *)value {
     // check value is NSObject
     if (!value || [value isEqual:[NSNull null]]) {

OptimizelySDKCore/OptimizelySDKCore/OPTLYFeatureFlag.m

@@ -1,5 +1,5 @@
 /****************************************************************************
- * Copyright 2017, Optimizely, Inc. and contributors                        *
+ * Copyright 2018, Optimizely, Inc. and contributors                        *
  *                                                                          *
  * Licensed under the Apache License, Version 2.0 (the "License");          *
  * you may not use this file except in compliance with the License.         *
@@ -19,6 +19,7 @@
 #import "OPTLYProjectConfig.h"
 #import "OPTLYExperiment.h"
 #import "OPTLYFeatureVariable.h"
+#import "OPTLYNSObject+Validation.h"
 
 @interface OPTLYFeatureFlag()
 
@@ -40,7 +41,7 @@ + (OPTLYJSONKeyMapper*)keyMapper
 }
 
 - (BOOL)isValid:(OPTLYProjectConfig *)config {
-    if ([OPTLYFeatureFlag isEmptyArray:self.experimentIds]) {
+    if ([self.experimentIds getValidArray] == nil) {
         return true;
     }
     if (self.experimentIds.count == 1) {
@@ -80,10 +81,4 @@ - (OPTLYFeatureVariable *)getFeatureVariableForKey:(NSString *)variableKey {
     return [NSDictionary dictionaryWithDictionary:map];
 }
 
-+ (BOOL)isEmptyArray:(NSObject*)array {
-    return (!array
-            || ![array isKindOfClass:[NSArray class]]
-            || (((NSArray *)array).count == 0));
-}
-
 @end

OptimizelySDKCore/OptimizelySDKCore/OPTLYNSObject+Validation.h

@@ -0,0 +1,53 @@
+/****************************************************************************
+ * Copyright 2018, Optimizely, Inc. and contributors                        *
+ *                                                                          *
+ * Licensed under the Apache License, Version 2.0 (the "License");          *
+ * you may not use this file except in compliance with the License.         *
+ * You may obtain a copy of the License at                                  *
+ *                                                                          *
+ *    http://www.apache.org/licenses/LICENSE-2.0                            *
+ *                                                                          *
+ * Unless required by applicable law or agreed to in writing, software      *
+ * distributed under the License is distributed on an "AS IS" BASIS,        *
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
+ * See the License for the specific language governing permissions and      *
+ * limitations under the License.                                           *
+ ***************************************************************************/
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface NSObject (Validation)
+
+/**
+ * Determines if object is a valid non-empty string type.
+ *
+ * @returns A NSString if object is valid string type, else return nil.
+ **/
+- (nullable NSString *)getValidString;
+
+/**
+ * Determines if object is a valid non-empty array type.
+ *
+ * @returns A NSArray if object is valid array type, else return nil.
+ **/
+- (nullable NSArray *)getValidArray;
+
+/**
+ * Determines if object is a valid non-empty dictionary type.
+ *
+ * @returns A NSDictionary if object is valid dictionary type, else return nil.
+ **/
+- (nullable NSDictionary *)getValidDictionary;
+
+/**
+ * Returns a string value for the object
+ *
+ * @returns A NSString if object is valid string type, else return empty string.
+ **/
+- (NSString *)getStringOrEmpty;
+
+@end
+
+NS_ASSUME_NONNULL_END