Poco::Data

class RowFormatter

Library: Data
Package: DataCore
Header: Poco/Data/RowFormatter.h

Description

Row formatter is an abstract class providing definition for row formatting functionality. For custom formatting strategies, inherit from this class and override formatNames() and formatValues() member functions.

Row formatter can be either passed to the RecordSet at construction time, like in the following example:

RecordSet rs(session. "SELECT * FROM Table", new MyRowFormater);

or it can be supplied to the statement as in the following example:

MyRowFormatter rf session << "SELECT * FROM Table", format(rf);

If no formatter is externally supplied to the statement, the SimpleRowFormatter is used. 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

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.

Inheritance

Known Derived Classes: SimpleRowFormatter

Member Summary

Member Functions: formatNames, formatValues, getMode, getTotalRowCount, postfix, prefix, reset, rowCount, setMode, setPostfix, setPrefix, setTotalRowCount, toString

Types

NameVec

typedef std::vector < std::string > NameVec;

NameVecPtr

typedef SharedPtr < std::vector < std::string > > NameVecPtr;

Ptr

typedef SharedPtr < RowFormatter > Ptr;

ValueVec

typedef std::vector < Poco::Dynamic::Var > ValueVec;

Enumerations

Mode

FORMAT_PROGRESSIVE

FORMAT_BULK

Constructors

RowFormatter

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.

Destructor

~RowFormatter virtual

virtual ~RowFormatter();

Destroys the RowFormatter.

Member Functions

formatNames virtual

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.

formatNames virtual

virtual void formatNames(
    const NameVecPtr pNames
);

Should be implemented to format the row fields names. The default implementation does nothing.

formatValues virtual

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.

formatValues virtual

virtual void formatValues(
    const ValueVec & vals
);

Should be implemented to format the row fields values. The default implementation does nothing.

getMode inline

Mode getMode() const;

Returns the formater mode.

getTotalRowCount inline

int getTotalRowCount() const;

Returns zero. Must be implemented by inheriting classes. Typically, total row count shall be set up front through setTotalRowCount() call.

postfix virtual inline

virtual const std::string & postfix() const;

Returns postfix string;

prefix virtual inline

virtual const std::string & prefix() const;

Returns prefix string;

reset

void reset();

Resets the formatter by setting prefix and postfix to empty strings and row count to INVALID_ROW_COUNT.

rowCount virtual inline

virtual int rowCount() const;

Returns INVALID_ROW_COUNT. Must be implemented by inheriting classes which maintain count of processed rows.

setMode inline

void setMode(
    Mode mode
);

Sets the fromatter mode.

setTotalRowCount inline

void setTotalRowCount(
    int count
);

Sets total row count.

toString virtual

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.

setPostfix protected inline

void setPostfix(
    const std::string & postfix
);

Sets the postfix for the formatter

setPrefix protected inline

void setPrefix(
    const std::string & prefix
);

Sets the prefix for the formatter.

Variables

INVALID_ROW_COUNT static

static const int INVALID_ROW_COUNT = - 1;