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ScaColDesc.h
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1 //# ScaColDesc.h: Templated class for description of table scalar columns
2 //# Copyright (C) 1994,1995,1996,1997,1998,2000
3 //# Associated Universities, Inc. Washington DC, USA.
4 //#
5 //# This library is free software; you can redistribute it and/or modify it
6 //# under the terms of the GNU Library General Public License as published by
7 //# the Free Software Foundation; either version 2 of the License, or (at your
8 //# option) any later version.
9 //#
10 //# This library is distributed in the hope that it will be useful, but WITHOUT
11 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13 //# License for more details.
14 //#
15 //# You should have received a copy of the GNU Library General Public License
16 //# along with this library; if not, write to the Free Software Foundation,
17 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18 //#
19 //# Correspondence concerning AIPS++ should be addressed as follows:
20 //# Internet email: aips2-request@nrao.edu.
21 //# Postal address: AIPS++ Project Office
22 //# National Radio Astronomy Observatory
23 //# 520 Edgemont Road
24 //# Charlottesville, VA 22903-2475 USA
25 //#
26 //# $Id$
27 
28 #ifndef TABLES_SCACOLDESC_H
29 #define TABLES_SCACOLDESC_H
30 
31 
32 //# Includes
33 #include <casacore/casa/aips.h>
35 
36 namespace casacore { //# NAMESPACE CASACORE - BEGIN
37 
38 //# Forward Declarations
39 class PlainColumn;
40 class ColumnSet;
41 
42 
43 // <summary>
44 // Templated class to define columns of scalars in tables
45 // </summary>
46 
47 // <reviewed reviewer="Gareth Hunt" date="94Nov17" tests="">
48 // </reviewed>
49 
50 // <use visibility=export>
51 
52 // <prerequisite>
53 // <li> BaseColumnDesc
54 // <li> TableDesc
55 // </prerequisite>
56 
57 // <etymology>
58 // This class builds descriptions of table columns where each cell (which
59 // may also be called a row) will hold a scalar value.
60 // </etymology>
61 
62 // <synopsis>
63 // ScalarColumnDesc is a templated class for defining a
64 // table column containing scalar values.
65 // Note that class
66 // <linkto class=ScalarRecordColumnDesc>ScalarRecordColumnDesc</linkto>
67 // has to be used to define the description of a column containing records.
68 // <p>
69 // The table values are handled by a data manager. This can be
70 // a storage manager to store the values in a file or it can be
71 // a virtual column engine to calculate them on-the-fly.
72 // Only the basic data types are allowed when storing in a file. These are:
73 // Bool, uChar, Short, uShort, Int, uInt, Int64, float, double,
74 // Complex, DComplex and String.
75 // <p>
76 // At table creation time (when a table gets created from a table
77 // description), each column needs to be bound to a data manager.
78 // If not done explicitly, the table system will bind a column to the
79 // default data manager defined in the column description.
80 // <p>
81 // A scalar column description consists of the following attributes:
82 // <ul>
83 // <li> Name, which has to be unique and must also be different
84 // from possible table keyword names.
85 // <li> Data type, which is determined by the template parameter
86 // (e.g. ArrayColumnDesc<Int>).
87 // <li> A data type id, which tells the unique name of non-standard
88 // data types (i.e. for data type == TpOther).
89 // <li> Comment, which defaults to an empty string.
90 // This serves purely as an informational string for the user.
91 // <li> Default value, which is only possible for the standard data types.
92 // It defaults to the undefined value defined in ValType.h.
93 // When a row gets added to a table, it is possible to
94 // initialize the column fields in the row with this default value.
95 // <li> Default data manager, which will be used if a column
96 // for a newly created table is not explicitly bound to a
97 // data manager.
98 // <li> Data manager group, which serves 2 purposes.
99 // Firstly it can be used in class SetupNewTable to bind a group
100 // of columns.
101 // Secondly, when the default data managers are used, it
102 // allows, for example, to have 2 StandardStMan storage managers.
103 // One for one group of columns and one for another group of columns.
104 // <li> Options. These are defined in ColumnDesc.h and can be combined
105 // by or-ing them.
106 // Currently only the Undefined flag applies to scalars.
107 // <li> Default keyword set, which defaults to an empty set.
108 // When a table column gets created from the description, it gets
109 // a copy of this keyword set as its initial keyword set.
110 // </ul>
111 //
112 // There are several constructors, which allow to define most
113 // of the above mentioned attributes. Others, like the default keyword
114 // set, have to be defined explicitly.
115 // <p>
116 // This class is derived from BaseColumnDesc, thus the functions
117 // in there also apply to this class.
118 // <br>
119 // Once a column description is setup satisfactorily, it must be added
120 // to a table description before it can be used by the table system.
121 // </synopsis>
122 
123 // <example>
124 // <srcblock>
125 // TableDesc tabDesc("tTableDesc", "1", TableDesc::New);
126 //
127 // // Add a scalar integer column ac, define keywords for it
128 // // and define a default value 0.
129 // ScalarColumnDesc<Int> acColumn("ac");
130 // acColumn.rwKeywordSet().define ("scale", Complex(0));
131 // acColumn.rwKeywordSet().define ("unit", "");
132 // acColumn.setDefault (0);
133 // tabDesc.addColumn (acColumn);
134 //
135 // // Add another column, now with data type String..
136 // // This can be added directly, because no special things like
137 // // keywords or default values have to be set.
138 // tabDesc.addColumn (ScalarColumnDesc<String>("name", "comments"));
139 // </srcblock>
140 // </example>
141 
142 // <motivation>
143 // Several column description classes are needed to allow the user
144 // to define attributes which are special for each column type.
145 // For scalars the special attribute is the default value.
146 // They all have to be templated to support arbitrary data types.
147 // </motivation>
148 
149 // <templating arg=T>
150 // <li> Default constructor
151 // <li> Copy constructor
152 // <li> Assignment operator
153 // <li> <src>static String dataTypeId(); // (not needed for builtin types)</src>
154 // This should return the unique "name" of the class.
155 // </templating>
156 
157 // <todo asof="$DATE:$">
158 //# A List of bugs, limitations, extensions or planned refinements.
159 // </todo>
160 
161 
162 template<class T>
163 class ScalarColumnDesc : public BaseColumnDesc
164 {
165 friend class ColumnDesc;
166 
167 public:
168  // Construct the column with the given name.
169  // The data manager type defaults to the StandardStMan storage manager.
170  // The data manager group defaults to the data manager type.
171  // The possible options are defined in ColumnDesc.h.
172  explicit ScalarColumnDesc (const String& name, int options = 0);
173 
174  // Construct the column with the given name and comment.
175  // The data manager type defaults to the StandardStMan storage manager.
176  // The data manager group defaults to the data manager type.
177  // The possible options are defined in ColumnDesc.h.
178  ScalarColumnDesc (const String& name, const String& comment,
179  int options = 0);
180 
181  // Construct the column with the given name, comment, and
182  // default data manager type and group.
183  // A blank data manager group defaults to the data manager type.
184  // The possible options are defined in ColumnDesc.h.
185  ScalarColumnDesc (const String& name, const String& comment,
186  const String& dataManName, const String& dataManGroup,
187  int options = 0);
188 
189  // Construct the column with the given name, comment, default
190  // data manager type and group, and default value.
191  // A blank data manager group defaults to the data manager type.
192  // The possible options are defined in ColumnDesc.h.
193  ScalarColumnDesc (const String& name, const String& comment,
194  const String& dataManName, const String& dataManGroup,
195  const T& defaultValue, int options = 0);
196 
197  // Copy constructor (copy semantics);
199 
201 
202  // Assignment (copy semantics);
204 
205  // Clone this column description.
206  BaseColumnDesc* clone() const;
207 
208  // Get the name of this class. It is used by the registration process.
209  // The template argument gets part of the name.
210  String className() const;
211 
212  // Set the default value.
213  void setDefault (const T& defaultValue)
215 
216  // Get the default value.
217  const T& defaultValue() const
218  { return defaultVal_p; }
219 
220  // Create a Column object out of this.
221  // This is used by class ColumnSet to construct a table column object.
222  virtual PlainColumn* makeColumn (ColumnSet*) const;
223 
224  // Make a ConcatColumn object out of the description.
225  virtual ConcatColumn* makeConcatColumn (ConcatTable*) const;
226 
227  // Show the column.
228  void show (ostream& os) const;
229 
230  // Register the construction function of this class.
231  void registerClass() const;
232 
233  // Create the object from AipsIO (this function is registered).
234  static BaseColumnDesc* makeDesc (const String& name);
235 
236 private:
237  T defaultVal_p; //# default value
238 
239  // Put the object.
240  virtual void putDesc (AipsIO&) const;
241 
242  // Get the object.
243  virtual void getDesc (AipsIO&);
244 };
245 
246 
247 //# Explicitly instantiate these templates in ScaColDesc_tmpl.cc
248  extern template class ScalarColumnDesc<Bool>;
249  extern template class ScalarColumnDesc<Char>;
250  extern template class ScalarColumnDesc<Short>;
251  extern template class ScalarColumnDesc<uShort>;
252  extern template class ScalarColumnDesc<Int>;
253  extern template class ScalarColumnDesc<uInt>;
254  extern template class ScalarColumnDesc<Int64>;
255  extern template class ScalarColumnDesc<Float>;
256  extern template class ScalarColumnDesc<Double>;
257  extern template class ScalarColumnDesc<Complex>;
258  extern template class ScalarColumnDesc<DComplex>;
259  extern template class ScalarColumnDesc<String>;
260 
261 
262 } //# NAMESPACE CASACORE - END
263 
264 #ifndef CASACORE_NO_AUTO_TEMPLATES
265 #include <casacore/tables/Tables/ScaColDesc.tcc>
266 #endif //# CASACORE_NO_AUTO_TEMPLATES
267 #endif
void setDefault(const T &defaultValue)
Set the default value.
Definition: ScaColDesc.h:213
ScalarColumnDesc< T > & operator=(const ScalarColumnDesc< T > &)
Assignment (copy semantics);.
Templated class to define columns of scalars in tables.
Definition: ScaColData.h:39
AipsIO is the object persistency mechanism of Casacore.
Definition: AipsIO.h:168
An abstract base class for table column descriptions.
Definition: BaseColDesc.h:107
Envelope class for the description of a table column.
Definition: ColumnDesc.h:131
String className() const
Get the name of this class.
Class to manage a set of table columns.
Definition: ColumnSet.h:93
const String & comment() const
Get comment string.
Definition: BaseColDesc.h:173
virtual void getDesc(AipsIO &)
Get the object.
void show(ostream &os) const
Show the column.
Int options() const
Get the options.
Definition: BaseColDesc.h:181
const T & defaultValue() const
Get the default value.
Definition: ScaColDesc.h:217
virtual ConcatColumn * makeConcatColumn(ConcatTable *) const
Make a ConcatColumn object out of the description.
virtual PlainColumn * makeColumn(ColumnSet *) const
Create a Column object out of this.
BaseColumnDesc * clone() const
Clone this column description.
Base class for a column in a plain table.
Definition: PlainColumn.h:84
void registerClass() const
Register the construction function of this class.
ScalarColumnDesc(const String &name, int options=0)
Construct the column with the given name.
String: the storage and methods of handling collections of characters.
Definition: String.h:223
static BaseColumnDesc * makeDesc(const String &name)
Create the object from AipsIO (this function is registered).
Class to view a concatenation of tables as a single table.
Definition: ConcatTable.h:118
const String & name() const
Get the name of the column.
Definition: BaseColDesc.h:138
virtual void putDesc(AipsIO &) const
Put the object.
A column in a concatenated table.
Definition: ConcatColumn.h:91
#define casacore
&lt;X11/Intrinsic.h&gt; #defines true, false, casacore::Bool, and String.
Definition: X11Intrinsic.h:42