DynamicAny non-initialized state capability

made DynamicAnyHolder::create() and is...() pure virtual functions virtual
(simplifies DynamicAnyHolderImpl implementation)
made DynamicAnyHolder default constructor protected
made DynamicAnyHolderImpl default constructor private
added DynamicAnyTest::testEmpty()

Data/include/Poco/Data/BLOB.h

@@ -373,6 +373,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Data::BLOB _val;
 };
 

Data/include/Poco/Data/Date.h

@@ -306,6 +306,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Data::Date _val;
 };
 

Data/include/Poco/Data/Time.h

@@ -310,6 +310,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Data::Time _val;
 };
 

Foundation/include/Poco/DynamicAny.h

@@ -53,6 +53,9 @@ class Foundation_API DynamicAny
 	/// DynamicAny puts forth the best effort to provide intuitive and reasonable conversion semantics and prevent 
 	/// unexpected data loss, particularly when performing narrowing or signedness conversions of numeric data types.
 	///
+	/// An attempt to convert or extract from a non-initialized (“empty”) DynamicAny variable shall result
+	/// in an exception being thrown.
+	///
 	/// Loss of signedness is not allowed for numeric values. This means that if an attempt is made to convert 
 	/// the internal value which is a negative signed integer to an unsigned integer type storage, a RangeException is thrown. 
 	/// Overflow is not allowed, so if the internal value is a larger number than the target numeric type size can accomodate, 
@@ -89,7 +92,7 @@ class Foundation_API DynamicAny
 {
 public:
 	DynamicAny();
-		/// Creates a DynamicAny holding an int with value 0.
+		/// Creates an empty DynamicAny.
 
 	template <typename T> 
 	DynamicAny(const T &val):
@@ -123,7 +126,11 @@ public:
 		/// into the result variable.
 		/// Throws a NotImplementedException if conversion is
 		/// not available for the given type.
+		/// Throws InvalidAccessException if DynamicAny is empty.
 	{
+		if (!_pHolder)
+			throw InvalidAccessException("Can not convert empty value.");
+
 		_pHolder->convert(val);
 	}
 	
@@ -139,7 +146,11 @@ public:
 		/// into the result variable.
 		/// Throws a NotImplementedException if conversion is
 		/// not available for the given type.
+		/// Throws InvalidAccessException if DynamicAny is empty.
 	{
+		if (!_pHolder)
+			throw InvalidAccessException("Can not convert empty value.");
+
 		T result;
 		_pHolder->convert(result);
 		return result;
@@ -154,7 +165,11 @@ public:
 		/// into the result variable.
 		/// Throws a NotImplementedException if conversion is
 		/// not available for the given type.
+		/// Throws InvalidAccessException if DynamicAny is empty.
 	{
+		if (!_pHolder)
+			throw InvalidAccessException("Can not convert empty value.");
+
 		T result;
 		_pHolder->convert(result);
 		return result;
@@ -167,12 +182,15 @@ public:
 		/// Must be instantiated with the exact type of
 		/// the stored value, otherwise a BadCastException
 		/// is thrown.
+		/// Throws InvalidAccessException if DynamicAny is empty.
 	{
 		if (_pHolder && _pHolder->type() == typeid(T))
 		{
-			DynamicAnyHolderImpl<T>* pHolder = static_cast<DynamicAnyHolderImpl<T>*>(_pHolder);
-			return pHolder->value();
+			DynamicAnyHolderImpl<T>* pHolderImpl = static_cast<DynamicAnyHolderImpl<T>*>(_pHolder);
+			return pHolderImpl->value();
 		}
+		else if (!_pHolder)
+			throw InvalidAccessException("Can not extract empty value.");
 		else
 			throw BadCastException();
 	}
@@ -397,6 +415,12 @@ public:
 	const std::type_info& type() const;
 		/// Returns the type information of the stored content.
 
+	void empty();
+		/// Empties DynamicAny.
+
+	bool isEmpty() const;
+		/// Returns true if empty.
+
 	bool isInteger() const;
 		/// Returns true if stored value is integer.
 
@@ -523,6 +547,19 @@ inline bool DynamicAny::operator != (const char* other) const
 }
 
 
+inline void DynamicAny::empty()
+{
+	delete _pHolder;
+	_pHolder = 0;
+}
+
+
+inline bool DynamicAny::isEmpty() const
+{
+	return 0 == _pHolder;
+}
+
+
 inline bool DynamicAny::isArray() const
 {
 	return _pHolder->isArray();

Foundation/include/Poco/DynamicAnyHolder.h

@@ -76,9 +76,6 @@ class Foundation_API DynamicAnyHolder
 	/// std::vector<DynamicAny> and DynamicStruct.
 {
 public:
-	DynamicAnyHolder();
-		/// Creates the DynamicAnyHolder.
-
 	virtual ~DynamicAnyHolder();
 		/// Destroys the DynamicAnyHolder.
 
@@ -88,36 +85,38 @@ public:
 	virtual const std::type_info& type() const = 0;
 		/// Returns the type information of the stored content.
 
-	virtual void convert(Int8& val) const = 0;
-	virtual void convert(Int16& val) const = 0;
-	virtual void convert(Int32& val) const = 0;
-	virtual void convert(Int64& val) const = 0;
-	virtual void convert(UInt8& val) const = 0;
-	virtual void convert(UInt16& val) const = 0;
-	virtual void convert(UInt32& val) const = 0;
-	virtual void convert(UInt64& val) const = 0;
-	virtual void convert(DateTime& val) const = 0;
-	virtual void convert(LocalDateTime& val) const = 0;
-	virtual void convert(Timestamp& val) const = 0;
-	virtual bool isArray() const = 0;
-	virtual bool isStruct() const = 0;
-	virtual bool isInteger() const = 0;
-	virtual bool isSigned() const = 0;
-	virtual bool isNumeric() const = 0;
-	virtual bool isString() const = 0;
-
+	virtual void convert(Int8& val) const;
+	virtual void convert(Int16& val) const;
+	virtual void convert(Int32& val) const;
+	virtual void convert(Int64& val) const;
+	virtual void convert(UInt8& val) const;
+	virtual void convert(UInt16& val) const;
+	virtual void convert(UInt32& val) const;
+	virtual void convert(UInt64& val) const;
+	virtual void convert(DateTime& val) const;
+	virtual void convert(LocalDateTime& val) const;
+	virtual void convert(Timestamp& val) const;
 #ifndef POCO_LONG_IS_64_BIT
 	void convert(long& val) const;
 	void convert(unsigned long& val) const;
 #endif
+	virtual void convert(bool& val) const;
+	virtual void convert(float& val) const;
+	virtual void convert(double& val) const;
+	virtual void convert(char& val) const;
+	virtual void convert(std::string& val) const;
 
-	virtual void convert(bool& val) const = 0;
-	virtual void convert(float& val) const = 0;
-	virtual void convert(double& val) const = 0;
-	virtual void convert(char& val) const = 0;
-	virtual void convert(std::string& val) const = 0;
+	virtual bool isArray() const;
+	virtual bool isStruct() const;
+	virtual bool isInteger() const;
+	virtual bool isSigned() const;
+	virtual bool isNumeric() const;
+	virtual bool isString() const;
 
 protected:
+	DynamicAnyHolder();
+		/// Creates the DynamicAnyHolder.
+
 	template <typename F, typename T>
 	void convertToSmaller(const F& from, T& to) const
 		/// This function is meant to convert signed numeric values from
@@ -244,6 +243,73 @@ private:
 //
 // inlines
 //
+
+inline void DynamicAnyHolder::convert(Int8& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for Int8");
+}
+
+
+inline void DynamicAnyHolder::convert(Int16& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for Int16");
+}
+
+
+inline void DynamicAnyHolder::convert(Int32& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for Int32");
+}
+
+
+inline void DynamicAnyHolder::convert(Int64& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for Int64");
+}
+
+
+inline void DynamicAnyHolder::convert(UInt8& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for UInt8");
+}
+
+
+inline void DynamicAnyHolder::convert(UInt16& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for UInt16");
+}
+
+
+inline void DynamicAnyHolder::convert(UInt32& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for UInt32");
+}
+
+
+inline void DynamicAnyHolder::convert(UInt64& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for UInt64");
+}
+
+
+inline void DynamicAnyHolder::convert(DateTime& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for DateTime");
+}
+
+
+inline void DynamicAnyHolder::convert(LocalDateTime& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for LocalDateTime");
+}
+
+
+inline void DynamicAnyHolder::convert(Timestamp& val) const
+{
+		throw NotImplementedException("No DynamicAnyHolder specialization for Timestamp");
+}
+
+
 #ifndef POCO_LONG_IS_64_BIT
 inline void DynamicAnyHolder::convert(long& val) const
 {
@@ -261,6 +327,61 @@ inline void DynamicAnyHolder::convert(unsigned long& val) const
 }
 #endif
 
+inline void DynamicAnyHolder::convert(bool& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for bool");
+}
+
+inline void DynamicAnyHolder::convert(float& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for float");
+}
+
+inline void DynamicAnyHolder::convert(double& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for double");
+}
+
+inline void DynamicAnyHolder::convert(char& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for char");
+}
+
+inline void DynamicAnyHolder::convert(std::string& val) const
+{
+	throw NotImplementedException("No DynamicAnyHolder specialization for std::string");
+}
+
+inline bool DynamicAnyHolder::isArray() const
+{
+	return false;
+}
+
+inline bool DynamicAnyHolder::isStruct() const
+{
+	return false;
+}
+
+inline bool DynamicAnyHolder::isInteger() const
+{
+	return false;
+}
+
+inline bool DynamicAnyHolder::isSigned() const
+{
+	return false;
+}
+
+inline bool DynamicAnyHolder::isNumeric() const
+{
+	return false;
+}
+
+inline bool DynamicAnyHolder::isString() const
+{
+	return false;
+}
+
 
 template <typename T>
 class DynamicAnyHolderImpl: public DynamicAnyHolder
@@ -280,10 +401,6 @@ class DynamicAnyHolderImpl: public DynamicAnyHolder
 	/// returning a const reference to the actual stored value.
 {
 public:
-	DynamicAnyHolderImpl()
-	{
-	}
-
 	~DynamicAnyHolderImpl()
 	{
 	}
@@ -313,100 +430,8 @@ public:
 		return type() == typeid(std::string);
 	}
 
-	void convert(Int8&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(Int16&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(Int32&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(Int64&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-	
-	void convert(UInt8&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(UInt16&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(UInt32&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(UInt64&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(bool&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(float&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(double&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(char&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(std::string&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(DateTime&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(LocalDateTime&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	void convert(Timestamp&) const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	DynamicAnyHolder* clone() const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	bool isArray() const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
-
-	bool isStruct() const
-	{
-		throw NotImplementedException("No DynamicAnyHolder specialization for type", typeid(T).name());
-	}
+private:
+	DynamicAnyHolderImpl();
 };
 
 
@@ -548,6 +573,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Int8 _val;
 };
 
@@ -692,6 +718,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Int16 _val;
 };
 
@@ -836,6 +863,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Int32 _val;
 };
 
@@ -980,6 +1008,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Int64 _val;
 };
 
@@ -1124,6 +1153,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	UInt8 _val;
 };
 
@@ -1268,6 +1298,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	UInt16 _val;
 };
 
@@ -1412,6 +1443,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	UInt32 _val;
 };
 
@@ -1562,6 +1594,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	UInt64 _val;
 };
 
@@ -1704,6 +1737,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	bool _val;
 };
 
@@ -1849,6 +1883,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	float _val;
 };
 
@@ -2000,6 +2035,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	double _val;
 };
 
@@ -2142,6 +2178,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	char _val;
 };
 
@@ -2317,6 +2354,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	std::string _val;
 };
 
@@ -2464,6 +2502,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	long _val;
 };
 
@@ -2608,6 +2647,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	unsigned long _val;
 };
 
@@ -2694,8 +2734,8 @@ public:
 
 	void convert(std::string& val) const
 	{
-		// Serialize in JSON format: note: although this a vector<T>, the code only 
-		// supports vector<DynamicAny>. We can't make this a total specialization,
+		// Serialize in JSON format: note: although this is a vector<T>, the code only 
+		// supports vector<DynamicAny>. Total specialization is not possible
 		// because of the cyclic dependency between DynamicAny and DynamicAnyHolder
 
 		// JSON format definition: [ n times: elem ',' ], no ',' for last elem
@@ -2718,17 +2758,17 @@ public:
 
 	void convert(DateTime&) const
 	{
-		throw BadCastException("vector -> DateTime");
+		throw BadCastException("Cannot cast collection type to non-collection type");
 	}
 
 	void convert(LocalDateTime&) const
 	{
-		throw BadCastException("vector -> LocalDateTime");
+		throw BadCastException("Cannot cast collection type to non-collection type");
 	}
 
 	void convert(Timestamp&) const
 	{
-		throw BadCastException("vector -> Timestamp");
+		throw BadCastException("Cannot cast collection type to non-collection type");
 	}
 
 	DynamicAnyHolder* clone() const
@@ -2782,6 +2822,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	std::vector<T> _val;
 };
 
@@ -2924,6 +2965,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	DateTime _val;
 };
 
@@ -3066,6 +3108,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	LocalDateTime _val;
 };
 
@@ -3208,6 +3251,7 @@ public:
 	}
 
 private:
+	DynamicAnyHolderImpl();
 	Timestamp _val;
 };
 

Foundation/src/DynamicAny.cpp

@@ -43,8 +43,7 @@
 namespace Poco {
 
 
-DynamicAny::DynamicAny():
-	_pHolder(new DynamicAnyHolderImpl<int>(0))
+DynamicAny::DynamicAny(): _pHolder(0)
 {
 }
 

Foundation/testsuite/src/DynamicAnyTest.cpp

@@ -2224,6 +2224,33 @@ void DynamicAnyTest::testGetIdxMustThrow(DynamicAny& a1, std::vector<DynamicAny>
 }
 
 
+void DynamicAnyTest::testEmpty()
+{
+	DynamicAny da;
+	assert (da.isEmpty());
+	da = "123";
+	int i = da.convert<int>();
+	assert (123 == i);
+	std::string s = da.extract<std::string>();
+	assert ("123" == s);
+	assert (!da.isEmpty());
+	da.empty();
+	assert (da.isEmpty());
+
+	try
+	{
+		int i = da;
+		fail ("must fail");
+	} catch (InvalidAccessException&) { }
+
+	try
+	{
+		int i = da.extract<int>();
+		fail ("must fail");
+	} catch (InvalidAccessException&) { }
+}
+
+
 void DynamicAnyTest::setUp()
 {
 }
@@ -2274,6 +2301,7 @@ CppUnit::Test* DynamicAnyTest::suite()
 	CppUnit_addTest(pSuite, DynamicAnyTest, testJSONDeserializeStruct);
 	CppUnit_addTest(pSuite, DynamicAnyTest, testJSONDeserializeComplex);
 	CppUnit_addTest(pSuite, DynamicAnyTest, testDate);
+	CppUnit_addTest(pSuite, DynamicAnyTest, testEmpty);
 
 	return pSuite;
 }

Foundation/testsuite/src/DynamicAnyTest.h

@@ -83,6 +83,7 @@ public:
 	void testJSONDeserializeStruct();
 	void testJSONDeserializeComplex();
 	void testDate();
+	void testEmpty();
 
 	void setUp();
 	void tearDown();