JsonKVMap.h

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// # JsonKVMap.h: Class to hold a collection of JSON key:value pairs
// # Copyright (C) 2016
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 of the License, or (at your
// # option) any later version.
// #
// # This library is distributed in the hope that it will be useful, but WITHOUT
// # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef CASA_JSONKVMAP_H
#define CASA_JSONKVMAP_H
 
#include <casacore/casa/Json/JsonValue.h>
#include <map>
#include <iosfwd>
 
namespace casacore {
 
// # Forward Declarations
class ValueHolder;
 
// <summary>
// Class to hold a collection of JSON key:value pairs.
// </summary>
 
// <use visibility=export>
// <reviewed reviewer="" date="" tests="tJsonKVMap">
// </reviewed>
 
// # <prerequisite>
// # </prerequisite>
 
// <synopsis>
// A JsonKVMap object is the result of a JSON file parsed by JsonParser.
// It is a map of name to a JsonValue object holding an arbitrary value
// (including a JsonKVMap for nested structs).
//
// JsonKVMap has functions to test if a given field is present and to
// get its JsonValue. It also has functions to get a scalar value
// where a default value is used if the key is undefined.
//
// JsonKVMap is derived from std::map, so all its functions are available.
// Iterators make standard iteration possible.
// </synopsis>
 
// <motivation>
// JSON is a commonly used interchange format.
// </motivation>
 
// # <todo asof="1996/03/10">
// #   <li>
// # </todo>
 
class JsonKVMap : public std::map<String, JsonValue> {
 public:
  // Define the iterator types.
  typedef std::map<String, JsonValue>::const_iterator const_iterator;
  typedef std::map<String, JsonValue>::iterator iterator;
 
  // Construct an empty map.
  JsonKVMap();
 
  // Copy constructor (copy semantics)
  JsonKVMap(const JsonKVMap& that);
 
  ~JsonKVMap();
 
  // Assignment (copy semantics)
  JsonKVMap& operator=(const JsonKVMap& that);
 
  // Is a key defined?
  Bool isDefined(const String& name) const { return find(name) != end(); }
 
  // Get the value of a key. An exception is thrown if undefined.
  const JsonValue& get(const String& name) const;
 
  // \name Get the typed value of a key
  // Use the default if not existing.
  // <group>
  Bool getBool(const String& name, Bool defVal) const;
  Int64 getInt(const String& name, Int64 defVal) const;
  double getDouble(const String& name, double defVal) const;
  DComplex getDComplex(const String& name, const DComplex& defVal) const;
  const String& getString(const String& name, const String& defVal) const;
  // </group>
 
  // Convert the map to a Record.
  Record toRecord() const;
 
  // \name Show the contents of the object
  // <group>
  void show(ostream&) const;
  friend ostream& operator<<(ostream&, const JsonKVMap&);
  // </group>
};
 
}  // namespace casacore
 
#endif