ArrColDesc.h

Classes

ArrayColumnDesc -- Templated class for description of table array columns (full description)

template<class T> class ArrayColumnDesc : public BaseColumnDesc

Interface

Public Members
ArrayColumnDesc (const String& name, Int ndim = -1, int options = 0)
ArrayColumnDesc (const String& name, const String& comment, Int ndim = -1, int options = 0)
ArrayColumnDesc (const String& name, const String& comment, const String& dataManName, const String& dataManGroup, Int ndim = -1, int options = 0)
ArrayColumnDesc (const String& name, const String& comment, const IPosition& shape, int options = 0)
ArrayColumnDesc (const String& name, const String& comment, const String& dataManName, const String& dataManGroup, const IPosition& shape, int options = 0)
ArrayColumnDesc (const ArrayColumnDesc<T>&)
~ArrayColumnDesc()
ArrayColumnDesc<T>& operator= (const ArrayColumnDesc<T>&)
BaseColumnDesc* clone() const
Bool isArray() const
String className() const
IPosition shape() const
void setDefault (const Array<T>& defaultValue)
const Array<T>* defaultValue() const
PlainColumn* makeColumn (ColumnSet*)
void show() const
Protected Members
ArrayColumnDesc (SimpleOrderedMap<String, BaseColumnDesc* (*)(const String&, AipsIO&)>&)
static BaseColumnDesc* makeDesc(const String& name, AipsIO&)
ArrayColumnDesc (AipsIO&)
void putDesc (AipsIO&) const

Description

Review Status

Reviewed By:
Gareth Hunt
Date Reviewed:
94Nov17

Prerequisite

Etymology

This class builds descriptions of table columns where each cell (which may also be called a row) will hold an array.

Synopsis

ArrayColumnDesc is a templated class for defining a table column containing arrays.

The table values are handled by a data manager. This can be a storage manager to store the values in a file or it can be a virtual column engine to calculate them on-the-fly. Only the basic data types are allowed when storing in a file. These are: Bool, uChar, Int, uInt, float, double, Complex, DComplex and String.

At table creation time (when a table gets created from a table description), each column needs to be bound to a data manager. If not done explicitly, the table system will bind a column to the default manager defined in the column description.

An array column description consists of the following attributes:

There are several constructors, which allow the definition of most of the above mentioned attributes. Others, like the default keyword set, have to be defined explicitly.

This class is derived from BaseColumnDesc, thus the functions in there also apply to this class.

Once a column description is set up satisfactorily, it must be added to a table description before it can be used by the table system.

Example

     TableDesc tabDesc("tTableDesc", "1", TableDesc::New);

     // Now define array columns.
     // This one is indirect and has no dimensionality mentioned yet.
     // Define the keyword UNIT in it.
     ArrayColumnDesc<Complex> arr1Column("Arr1", "comment for Arr1");
     arr1Column.keywordSet().keysString()("UNIT") = "Jy";
     tabDesc.addColumn (arr1Column);

     // This one is indirect and has 3-dim arrays.
     tabDesc.addColumn (ArrayColumnDesc<Int>("Arr2",
                                             "comment for Arr2",
                                             3));
     // This one is direct and has 2-dim arrays with axis lengths 4 and 7.
     tabDesc.addColumn (ArrayColumnDesc<uInt>("Arr3",
                                              "comment for Arr1",
        				        IPosition(2,4,7),
 					        ColumnDesc::Direct));

Motivation

Several column description classes are needed to allow the user to define attributes which are special for each column type. For scalars the special attribute is the default value. They all have to be templated to support arbitrary data types.

To Do

Member Description

ArrayColumnDesc (const String& name, Int ndim = -1, int options = 0)

Construct the column with the given name and dimensionality. The data manager type defaults to the StManAipsIO storage manager. The data manager group defaults to the data manager type. Ndim <=0 means that the number of dimensions is free and will be defined when creating the table (rows). Ndim>0 means that the arrays in this column must have the given dimensionality. The possible options are defined in ColumnDesc.h.

ArrayColumnDesc (const String& name, const String& comment, Int ndim = -1, int options = 0)

Construct the column with the given name, dimensionality, and comment. The data manager type defaults to the StManAipsIO storage manager. The data manager group defaults to the data manager type. Ndim <=0 means that the number of dimensions is free and will be defined when creating the table (rows). Ndim>0 means that the arrays in this column must have the given dimensionality. The possible options are defined in ColumnDesc.h.

ArrayColumnDesc (const String& name, const String& comment, const String& dataManName, const String& dataManGroup, Int ndim = -1, int options = 0)

Construct the column with the given name, dimensionality, comment, and default data manager type and group. A blank data manager group defaults to the data manager type. Ndim <=0 means that the number of dimensions is free and will be defined when creating the table (rows). Ndim>0 means that the arrays in this column must have the given dimensionality. The possible options are defined in ColumnDesc.h.

ArrayColumnDesc (const String& name, const String& comment, const IPosition& shape, int options = 0)

Construct the column with the given name, shape, and comment. The data manager type defaults to the StManAipsIO storage manager. The data manager group defaults to the data manager type. The possible options are defined in ColumnDesc.h. This constructor can only be used for direct arrays, because the shape of indirect arrays can only be set per row.

ArrayColumnDesc (const String& name, const String& comment, const String& dataManName, const String& dataManGroup, const IPosition& shape, int options = 0)

Construct the column with the given name, shape, comment, and default data manager type and group. A blank data manager group defaults to the data manager type. The possible options are defined in ColumnDesc.h. This constructor can only be used for direct arrays, because the shape of indirect arrays can only be set per row.

ArrayColumnDesc (const ArrayColumnDesc<T>&)

Copy constructor (copy semantics);

~ArrayColumnDesc()

ArrayColumnDesc<T>& operator= (const ArrayColumnDesc<T>&)

Assignment (copy semantics);

BaseColumnDesc* clone() const

Clone this column description to another.

Bool isArray() const

The column is an array.

String className() const

Get the name of this class. It is used by the registration process. The template argument gets part of the name.

IPosition shape() const

Get the shape. If no shape has been defined, a zero-length IPosition is returned.

void setDefault (const Array<T>& defaultValue)

Set the default value. This can only be done if the shape of the arrays in the column has defined, thus it can only be done for direct arrays. The shape of the default value array must match that shape.

const Array<T>* defaultValue() const

Get the default value. If no default value was defined, a zero pointer is returned.

PlainColumn* makeColumn (ColumnSet*)

Create a Column object out of this. This is used by class ColumnSet to construct a table column object.

void show() const

Show the column.

ArrayColumnDesc (SimpleOrderedMap<String, BaseColumnDesc* (*)(const String&, AipsIO&)>&)

default value

Construct the object to register its class.

static BaseColumnDesc* makeDesc(const String& name, AipsIO&)

Create the object from AipsIO (this function is registered).

ArrayColumnDesc (AipsIO&)

Construct object from AipsIO (used by makeDesc).

void putDesc (AipsIO&) const

Put the object.


Copyright © 1995 Associated Universities Inc., Washington, D.C.