class Attribute

(Return to index)

A representation of an Object attribute.

Contains a pointer to the polymorphic attribute value (derived from AttributeBase, and a pointer to the polymorphic attribute parser (derived from AttributeHandler).

Type:	Instantiable
Include file:	./AbstractObjects/Attribute.hh

Synopsis (including inherited members):

• Public members:
  • Attribute () ;
  • Attribute (const Attribute&) ;
  • Attribute (AttributeHandler*,AttributeBase*) ;
  • ~Attribute () ;
  • const Attribute& operator= (const Attribute&) ;
  • operator bool ()const ;
  • void doomGet (const DoomReader&,int) ;
  • void doomPut (DoomWriter&,int)const ;
  • AttributeBase& getBase ()const ;
  • string getImage ()const ;
  • AttributeHandler& getHandler ()const ;
  • const string& getHelp ()const ;
  • const string& getName ()const ;
  • const string& getType ()const ;
  • bool isDeferred ()const ;
  • void setDeferred (bool) ;
  • bool isExpression ()const ;
  • bool isReadOnly ()const ;
  • void setReadOnly (bool) ;
  • void parse (Statement&,bool) ;
  • void parseComponent (Statement&,bool,int) ;
  • void set (AttributeBase*) ;
  • void setDefault () ;
  • void print (std::ostream&,int&)const ;

Documentation:

• Public members:

  Attribute () ;

  Default constructor.
  Leaves both pointers NULL. An object constructed by the default constructor must be initialized using assignment before it can be used. Failing to do so may cause a program crash.

  Attribute (const Attribute&) ;

  Copy constructor.
  Both value and parser are shared with rhs.

  Attribute (AttributeHandler*,AttributeBase*) ;

  Constructor defining a parser and an optional value.
  The default value is ``undefined''.

  void doomGet (const DoomReader&,int) ;

  Read attribute from the DOOM data base.
  Use the contained parser to read the attribute.

  void doomPut (DoomWriter&,int)const ;

  Write attribute to the DOOM data base.
  Use the contained parser to write the attribute.

  AttributeBase& getBase ()const ;

  Return reference to polymorphic value.

  AttributeHandler& getHandler ()const ;

  Return a reference to the parser.

  const string& getHelp ()const ;

  Return the help string.
  This string is stored in the parser object.

  string getImage ()const ;

  Return printable representation.
  This string duplicates the input expression defining the attribute.

  const string& getName ()const ;

  Return the attribute name.
  This string is stored in the parser object.

  const string& getType ()const ;

  Return the attribute type.
  This string ("real", "logical", etc.) is stored in the parser object.

  bool isDeferred ()const ;

  Return deferred flag.
  If this flag is set, any expression is re-evaluated each time the value is fetched. Normally attribute evaluation is not deferred, i. e. any expression is evaluated only the first time the value is fetched after a new definition has been read. See Expressions::ADeferred and Expressions::SDeferred for information.

  bool isExpression ()const ;

  Test for expression.
  Return true, if the attribute is defined as an expression.

  bool isReadOnly ()const ;

  Test for read only.
  Return true, if the attribute cannot be redefined by the user.

  operator bool ()const ;

  Test for valid pointer.
  Returns true, when the value is defined (non-null pointer).

  void parse (Statement&,bool) ;

  Parse attribute.
  Use the contained parser to parse a new value for the attribute.

  void parseComponent (Statement&,bool,int) ;

  Parse array component.
  Use the contained parser to parse a new value for an existing vector component. If the attribute is a scalar value, or if the component does not exist, this method throws MadException.

  void print (std::ostream&,int&)const ;

  Print attribute.
  Print the attribute name, followed by an equals sign and its value.

  void set (AttributeBase*) ;

  Define new value.
  Assign a new value. The value must be compatible with the parser type, otherwise a MadException is thrown.

  void setDefault () ;

  Assign default value.
  Set the attribute value to the default value stored in the parser. If no default value exists, set it to ``undefined''.

  void setDeferred (bool) ;

  Set read-only flag.
  If this flag is set, the attribute cannot be redefined by the user. See Expressions::ADeferred and Expressions::SDeferred for information.

  void setReadOnly (bool) ;

  Set read-only flag.
  Set or reset the attribute's read-only flag.