fixed NPE for objc client

Author: fehguy

modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java

@@ -815,7 +815,8 @@ public CodegenProperty fromProperty(String name, Property p) {
           			if (property.items.isEnum) {
           				  property.datatypeWithEnum = property.datatypeWithEnum.replace(property.items.baseType,
           						property.items.datatypeWithEnum);
-          				  property.defaultValue = property.defaultValue.replace(property.items.baseType, property.items.datatypeWithEnum);
+                            if(property.defaultValue != null)
+          				        property.defaultValue = property.defaultValue.replace(property.items.baseType, property.items.datatypeWithEnum);
           			}
         		}
       	} else if (p instanceof MapProperty) {

modules/swagger-codegen/src/main/resources/JavaInflector/inflector.mustache

@@ -4,3 +4,7 @@ swaggerUrl: ./src/main/swagger/swagger.json
 modelMappings:
   {{#models}}{{#model}}{{classname}} : {{modelPackage}}.{{classname}}{{/model}}
   {{/models}}
+entityProcessors:
+  - json
+  - xml
+  - yaml