IsNull.h
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1 /* Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.
2 
3  This file is part of the TerraLib - a Framework for building GIS enabled applications.
4 
5  TerraLib is free software: you can redistribute it and/or modify
6  it under the terms of the GNU Lesser General Public License as published by
7  the Free Software Foundation, either version 3 of the License,
8  or (at your option) any later version.
9 
10  TerraLib is distributed in the hope that it will be useful,
11  but WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  GNU Lesser General Public License for more details.
14 
15  You should have received a copy of the GNU Lesser General Public License
16  along with TerraLib. See COPYING. If not, write to
17  TerraLib Team at <terralib-team@terralib.org>.
18  */
19 
20 /*!
21  \file terralib/dataaccess/query/IsNull.h
22 
23  \brief Tells if a value is NULL.
24 */
25 
26 #ifndef __TERRALIB_DATAACCESS_INTERNAL_ISNULL_H
27 #define __TERRALIB_DATAACCESS_INTERNAL_ISNULL_H
28 
29 // TerraLib
30 #include "FunctionNames.h"
31 #include "UnaryFunction.h"
32 
33 namespace te
34 {
35  namespace da
36  {
37  /*!
38  \class IsNull
39 
40  \brief Tells if a value is NULL.
41 
42  This function is just a syntatic-suggar.
43 
44  \sa UnaryFunction
45  */
47  {
48  public:
49 
51 
52  /*!
53  \brief Constructor.
54 
55  \param arg The argument.
56 
57  \note The addition operator will take the ownership of the given arguments.
58  */
59  IsNull(Expression* arg) : UnaryFunction(FunctionNames::sm_IsNull, arg) {}
60 
61  /*!
62  \brief Constructor.
63 
64  \param arg The argument.
65  */
66  IsNull(const Expression& arg) : UnaryFunction(FunctionNames::sm_IsNull, arg) {}
67 
68  /*! \brief Copy constructor. */
69  IsNull(const IsNull& rhs);
70 
71  /*! \brief Destructor. */
72  ~IsNull() {}
73 
74  /*! Assignment operator. */
75  IsNull& operator=(const IsNull& rhs);
76 
77  /*! \brief It creates a new copy of this expression. */
78  Expression* clone() const;
79  };
80 
81  } // end namespace da
82 } // end namespace te
83 
84 #endif // __TERRALIB_DATAACCESS_INTERNAL_ISNULL_H
85 
A base class for unary functions.
~IsNull()
Destructor.
Definition: IsNull.h:72
A base class for unary functions.
Definition: UnaryFunction.h:43
This is an abstract class that models a query expression.
Definition: Expression.h:47
URI C++ Library.
TE_DEFINE_VISITABLE IsNull(Expression *arg)
Constructor.
Definition: IsNull.h:59
Tells if a value is NULL.
Definition: IsNull.h:46
#define TE_DEFINE_VISITABLE
Definition: BaseVisitable.h:75
IsNull(const Expression &arg)
Constructor.
Definition: IsNull.h:66
A static class with global function name definitions.
#define TEDATAACCESSEXPORT
You can use this macro in order to export/import classes and functions from this module.
Definition: Config.h:97
A static class with global function name definitions.
Definition: FunctionNames.h:45