RowFormatter - progressive and bulk formatting modes

Data/include/Poco/Data/RecordSet.h

@@ -358,6 +358,9 @@ public:
 		/// Copies the column names to the target output stream.
 		/// Copied string is formatted by the current RowFormatter.
 
+	void formatNames() const;
+		/// Formats names using the current RowFormatter.
+
 	std::ostream& copyValues(std::ostream& os, 
 		std::size_t offset = 0, 
 		std::size_t length = RowIterator::POSITION_END) const;
@@ -369,6 +372,14 @@ public:
 		/// cause RangeException to be thrown.
 		/// Copied string is formatted by the current RowFormatter.
 
+	void formatValues(std::size_t offset, std::size_t length) const;
+		/// Formats values using the current RowFormatter.
+		/// The data set to be formatted is starting at the specified offset 
+		/// from the recordset beginning. The number of rows to be copied
+		/// is specified by length argument.
+		/// An invalid combination of offset/length arguments shall
+		/// cause RangeException to be thrown.
+
 	std::ostream& copy(std::ostream& os,
 		std::size_t offset = 0,
 		std::size_t length = RowIterator::POSITION_END) const;
@@ -622,6 +633,12 @@ inline const RowFilter* RecordSet::getFilter() const
 }
 
 
+inline void RecordSet::formatNames() const
+{
+	(*_pBegin)->formatNames();
+}
+
+
 /* TODO
 namespace Keywords {
 

Data/include/Poco/Data/Row.h

@@ -195,10 +195,16 @@ public:
 		/// Resets the sorting criteria to field 0 only.
 
 	const std::string& namesToString() const;
-		/// Converts the row names to string.
+		/// Converts the column names to string.
+
+	void formatNames() const;
+		/// Fomats the column names.
 
 	const std::string& valuesToString() const;
-		/// Converts the row values to string.
+		/// Converts the row values to string and returns the formated string.
+
+	void formatValues() const;
+		/// Fomats the row values.
 
 	bool operator == (const Row& other) const;
 		/// Equality operator.
@@ -243,12 +249,12 @@ private:
 	bool isEqualSize(const Row& other) const;
 	bool isEqualType(const Row& other) const;
 
-	NameVecPtr           _pNames;
-	ValueVec             _values;
-	SortMapPtr           _pSortMap;
-	RowFormatterPtr      _pFormatter;
-	mutable std::string  _nameStr;
-	mutable std::string  _valueStr;
+	NameVecPtr              _pNames;
+	ValueVec                _values;
+	SortMapPtr              _pSortMap;
+	mutable RowFormatterPtr _pFormatter;
+	mutable std::string     _nameStr;
+	mutable std::string     _valueStr;
 };
 
 
@@ -319,6 +325,12 @@ inline const std::string& Row::valuesToString() const
 }
 
 
+inline void Row::formatValues() const
+{
+	return _pFormatter->formatValues(values());
+}
+
+
 } } // namespace Poco::Data
 
 

Data/include/Poco/Data/RowFormatter.h

@@ -71,6 +71,23 @@ class Data_API RowFormatter
 	/// Statement always has the ownership of the row formatter and shares
 	/// it with rows through RecordSet.
 	///
+	/// To accomodate for various formatting needs, a formatter can operate in two modes:
+	/// 
+	///	  - progressive: formatted individual row strings are gemerated and returned from each 
+	///     call to formatValues;
+	///     std::string& formatNames(const NameVecPtr, std::string&) and
+	///     std::string& formatValues(const ValueVec&, std::string&) member calls should be
+	///     used in this case; this is the default mode
+	///
+	///   - bulk: formatted resulting string is accumulated internally and obtained at
+	///     the end of iteration via toString() member function;
+	///     void formatNames(const NameVecPtr) and
+	///     void formatValues(const ValueVec&) member calls should be used in this case
+	///
+	/// When formatter is used in conjunction with Row/RecordSet, the formatting members corresponding
+	/// to the formater mode are expected to be implemented. If a call is propagated to this parent
+	/// class, the functions do nothing or silently return empty string respectively.
+	///
 {
 public:
 	typedef std::vector<std::string>             NameVec;
@@ -79,17 +96,39 @@ public:
 
 	static const int INVALID_ROW_COUNT = -1;
 
-	RowFormatter(const std::string& prefix = "", const std::string& postfix = "");
+	enum Mode
+	{
+		FORMAT_PROGRESSIVE,
+		FORMAT_BULK
+	};
+
+	RowFormatter(const std::string& prefix = "",
+		const std::string& postfix = "",
+		Mode mode = FORMAT_PROGRESSIVE);
 		/// Creates the RowFormatter and sets the prefix and postfix to specified values.
 
 	virtual ~RowFormatter();
 		/// Destroys the RowFormatter.
 
-	virtual std::string& formatNames(const NameVecPtr pNames, std::string& formattedNames) const = 0;
-		/// Formats the row field names.
+	virtual std::string& formatNames(const NameVecPtr pNames, std::string& formattedNames);
+		/// Should be implemented to format the row fields names and return the formatted string.
+		/// The default implementation clears the names string and returns it.
 
-	virtual std::string& formatValues(const ValueVec& vals, std::string& formattedValues) const = 0;
-		/// Formats the row values.
+	virtual void formatNames(const NameVecPtr pNames);
+		/// Should be implemented to format the row fields names.
+		/// The default implementation does nothing.
+
+	virtual std::string& formatValues(const ValueVec& vals, std::string& formattedValues);
+		/// Should be implemented to format the row fields values and return the formatted string.
+		/// The default implementation clears the values string and returns it.
+
+	virtual void formatValues(const ValueVec& vals);
+		/// Should be implemented to format the row fields values.
+		/// The default implementation does nothing.
+
+	virtual const std::string& toString();
+		/// Throws NotImplementedException. Formatters operating in bulk mode should 
+		/// implement this member function to return valid pointer to the formatted result.
 
 	virtual int rowCount() const;
 		/// Returns INVALID_ROW_COUNT. Must be implemented by inheriting classes
@@ -113,18 +152,25 @@ public:
 		/// Resets the formatter by setting prefix and postfix
 		/// to empty strings and row count to INVALID_ROW_COUNT.
 
+	Mode getMode() const;
+		/// Returns the formater mode.
+
+	void setMode(Mode mode);
+		/// Sets the fromatter mode.
+
 protected:
 
-	void setPrefix(const std::string& prefix) const;
+	void setPrefix(const std::string& prefix);
 		/// Sets the prefix for the formatter.
 
-	void setPostfix(const std::string& postfix) const;
+	void setPostfix(const std::string& postfix);
 		/// Sets the postfix for the formatter
 
 private:
 
 	mutable std::string _prefix;
 	mutable std::string _postfix;
+	Mode                _mode;
 	int                 _totalRowCount;
 };
 
@@ -150,13 +196,13 @@ inline void RowFormatter::setTotalRowCount(int count)
 }
 
 
-inline void RowFormatter::setPrefix(const std::string& prefix) const
+inline void RowFormatter::setPrefix(const std::string& prefix)
 {
 	_prefix = prefix;
 }
 
 
-inline void RowFormatter::setPostfix(const std::string& postfix) const
+inline void RowFormatter::setPostfix(const std::string& postfix)
 {
 	_postfix = postfix;
 }
@@ -174,6 +220,18 @@ inline const std::string& RowFormatter::postfix() const
 }
 
 
+inline RowFormatter::Mode RowFormatter::getMode() const
+{
+	return _mode;
+}
+
+
+inline void RowFormatter::setMode(Mode mode)
+{
+	_mode = mode;
+}
+
+
 namespace Keywords {
 
 

Data/include/Poco/Data/SimpleRowFormatter.h

@@ -73,10 +73,10 @@ public:
 	void swap(SimpleRowFormatter& other);
 		/// Swaps the row formatter with another one.
 
-	std::string& formatNames(const NameVecPtr pNames, std::string& formattedNames) const;
+	std::string& formatNames(const NameVecPtr pNames, std::string& formattedNames);
 		/// Formats the row field names.
 
-	std::string& formatValues(const ValueVec& vals, std::string& formattedValues) const;
+	std::string& formatValues(const ValueVec& vals, std::string& formattedValues);
 		/// Formats the row values.
 
 	int rowCount() const;
@@ -90,7 +90,7 @@ public:
 
 private:
 	std::streamsize _colWidth;
-	mutable int     _rowCount;
+	int             _rowCount;
 };
 
 

Data/samples/RowFormatter/src/RowFormatter.cpp

@@ -63,7 +63,7 @@ public:
 		setPostfix(os.str());
 	}
 
-	std::string& formatNames(const NameVecPtr pNames, std::string& formattedNames) const
+	std::string& formatNames(const NameVecPtr pNames, std::string& formattedNames)
 	{
 		std::ostringstream str;
 
@@ -76,7 +76,7 @@ public:
 		return formattedNames = str.str();
 	}
 
-	std::string& formatValues(const ValueVec& vals, std::string& formattedValues) const
+	std::string& formatValues(const ValueVec& vals, std::string& formattedValues)
 	{
 		std::ostringstream str;
 

Data/src/RecordSet.cpp

@@ -329,26 +329,40 @@ std::ostream& RecordSet::copyNames(std::ostream& os) const
 
 std::ostream& RecordSet::copyValues(std::ostream& os, std::size_t offset, std::size_t length) const
 {
-	RowIterator itBegin = *_pBegin + offset;
-	RowIterator itEnd = (RowIterator::POSITION_END != length) ? itBegin + length : *_pEnd;
-	std::string val;
-	for (; itBegin != itEnd; ++itBegin)
-	{
-		val = itBegin->valuesToString();
-		if (!val.empty()) os << val;
-	}
+	RowIterator it = *_pBegin + offset;
+	RowIterator end = (RowIterator::POSITION_END != length) ? it + length : *_pEnd;
+	std::copy(it, end, std::ostream_iterator<Row>(os));
 	return os;
 }
 
 
+void RecordSet::formatValues(std::size_t offset, std::size_t length) const
+{
+	RowIterator it = *_pBegin + offset;
+	RowIterator end = (RowIterator::POSITION_END != length) ? it + length : *_pEnd;
+	std::string val;
+	for (; it != end; ++it) it->formatValues();
+}
+
+
 std::ostream& RecordSet::copy(std::ostream& os, std::size_t offset, std::size_t length) const
 {
 	RowFormatter& rf = const_cast<RowFormatter&>((*_pBegin)->getFormatter());
 	rf.setTotalRowCount(getTotalRowCount());
-	os << rf.prefix();
-	copyNames(os);
-	copyValues(os, offset, length);
-	os << rf.postfix();
+	if (RowFormatter::FORMAT_PROGRESSIVE == rf.getMode())
+	{
+		os << rf.prefix();
+		copyNames(os);
+		copyValues(os, offset, length);
+		os << rf.postfix();
+	}
+	else
+	{
+		formatNames();
+		formatValues(offset, length);
+		os << rf.toString();
+	}
+
 	return os;
 }
 

Data/src/Row.cpp

@@ -398,4 +398,13 @@ const std::string& Row::namesToString() const
 }
 
 
+void Row::formatNames() const
+{
+	if (!_pNames)
+		throw NullPointerException();
+
+	return _pFormatter->formatNames(names());
+}
+
+
 } } // namespace Poco::Data

Data/src/RowFormatter.cpp

@@ -43,9 +43,12 @@ namespace Poco {
 namespace Data {
 
 
-RowFormatter::RowFormatter(const std::string& prefix, const std::string& postfix):
+RowFormatter::RowFormatter(const std::string& prefix,
+	const std::string& postfix,
+	Mode mode):
 	_prefix(prefix), 
 	_postfix(postfix),
+	_mode(mode),
 	_totalRowCount(0)
 {
 }
@@ -56,6 +59,38 @@ RowFormatter::~RowFormatter()
 }
 
 
+std::string& RowFormatter::formatNames(const NameVecPtr pNames, std::string& formattedNames)
+{
+	formattedNames.clear();
+	return formattedNames;
+}
+
+
+void RowFormatter::formatNames(const NameVecPtr pNames)
+{
+	return;
+}
+
+
+std::string& RowFormatter::formatValues(const ValueVec& vals, std::string& formattedValues)
+{
+	formattedValues.clear();
+	return formattedValues;
+}
+
+
+void RowFormatter::formatValues(const ValueVec& vals)
+{
+	return;
+}
+
+
+const std::string& RowFormatter::toString()
+{
+	throw NotImplementedException("RowFormatter::toString()");
+}
+
+
 void RowFormatter::reset()
 {
 	_prefix = "";

Data/src/SimpleRowFormatter.cpp

@@ -79,7 +79,7 @@ void SimpleRowFormatter::swap(SimpleRowFormatter& other)
 }
 
 
-std::string& SimpleRowFormatter::formatNames(const NameVecPtr pNames, std::string& formattedNames) const
+std::string& SimpleRowFormatter::formatNames(const NameVecPtr pNames, std::string& formattedNames)
 {
 	_rowCount = 0;
 
@@ -98,7 +98,7 @@ std::string& SimpleRowFormatter::formatNames(const NameVecPtr pNames, std::strin
 }
 
 
-std::string& SimpleRowFormatter::formatValues(const ValueVec& vals, std::string& formattedValues) const
+std::string& SimpleRowFormatter::formatValues(const ValueVec& vals, std::string& formattedValues)
 {
 	std::ostringstream str;