type::Primitive: add getValue(<default-val> method)

changelog/1.3.0.md

@@ -38,9 +38,13 @@ Now it's much easier to use `oatpp::String` since `oatpp::String` is now wrapper
 
 {
   oatpp::String s1 = "Hello";
-  std::string s2 = s1;   // s1 is used a l-value with a typecast operator
+  std::string s2 = s1;   // implicit cast
 }
 
+{
+  oatpp::String s1 = nullptr;
+  std::string s2 = s1;   // implicit cast from null-value trows runtime_error 
+}
 
 {
   oatpp::String s1 = "Hello";
@@ -63,6 +67,14 @@ Now it's much easier to use `oatpp::String` since `oatpp::String` is now wrapper
 
   OATPP_LOGD("TEST", "str='%s'", s3->c_str()); // prints 'Hello World'
 }
+
+{
+  oatpp::String s1 = nullptr;
+  oatpp::String s2 = "hello";
+  
+  OATPP_ASSERT(s1.getValue("default") == "default")
+  OATPP_ASSERT(s2.getValue("default") == "hello")
+}
 ```
 
 ## ConnectionPool::get() Timeout

src/oatpp/core/data/mapping/type/Primitive.cpp

@@ -79,6 +79,13 @@ bool String::equalsCI_ASCII(const char* other) {
   return ciLabel == other;
 }
 
+std::string String::getValue(const std::string& defaultValue) {
+  if(m_ptr) {
+    return *m_ptr;
+  }
+  return defaultValue;
+}
+
 String operator + (const char* a, const String& b) {
   data::stream::BufferOutputStream stream;
   stream << a << b;

src/oatpp/core/data/mapping/type/Primitive.hpp

@@ -209,6 +209,13 @@ public:
    */
   bool equalsCI_ASCII(const char* str);
 
+  /**
+   * Get underlying value.
+   * @param defaultValue - value to return in case stored value is `nullptr`.
+   * @return - value or `defaultValue` if stored value is `nullptr`.
+   */
+  std::string getValue(const std::string& defaultValue);
+
   template<typename T,
     typename enabled = typename std::enable_if<std::is_same<T, std::nullptr_t>::value, void>::type
   >
@@ -346,6 +353,13 @@ public:
     return *this->m_ptr;
   }
 
+  TValueType getValue(const TValueType& defaultValue) {
+    if(this->m_ptr) {
+      return *this->m_ptr;
+    }
+    return defaultValue;
+  }
+
 };
 
 /**

test/oatpp/core/data/mapping/type/PrimitiveTest.cpp

@@ -244,6 +244,14 @@ void PrimitiveTest::onRun() {
     OATPP_LOGI(TAG, "OK");
   }
 
+  {
+    OATPP_LOGI(TAG, "check default value");
+    oatpp::UInt8 s0;
+    oatpp::UInt8 s1 = 255;
+    OATPP_ASSERT(s0.getValue(128) == 128)
+    OATPP_ASSERT(s1.getValue(128) == 255)
+  }
+
 }
 
 }}}}}}

test/oatpp/core/data/mapping/type/StringTest.cpp

@@ -314,6 +314,14 @@ void StringTest::onRun() {
 
   }
 
+  {
+    OATPP_LOGI(TAG, "check default value");
+    oatpp::String s0;
+    oatpp::String s1 = "hello";
+    OATPP_ASSERT(s0.getValue("def") == "def")
+    OATPP_ASSERT(s1.getValue("def") == "hello")
+  }
+
 }
 
 }}}}}}