/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2008 INRIA
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
*/
#ifndef GLOBAL_VALUE_H
#define GLOBAL_VALUE_H
#include <string>
#include <vector>
#include "ptr.h"
#include "attribute.h"
namespace ns3 {
/**
* \ingroup Core
*
* \brief hold a so-called 'global value'.
*
* Instances of this class are expected to be allocated as static
* global variables and should be used to store configurable global state.
* GlobalValues can be set directly by calling ns3::GlobalValue::SetValue
* but they can also be set through the NS_GLOBAL_VALUE environment variable.
* For example, NS_GLOBAL_VALUE='Name=Value;OtherName=OtherValue;' would set
* global values Name and OtherName to Value and OtherValue respectively.
*
* Users of the ns3::CommandLine class also get the ability to set global
* values through commandline arguments to their program: --Name=Value will
* set global value Name to Value.
*/
class GlobalValue
{
typedef std::vector<GlobalValue *> Vector;
public:
typedef Vector::const_iterator Iterator;
/**
* \param name the name of this global value.
* \param help some help text which describes the purpose of this
* global value.
* \param initialValue the value to assign to this global value
* during construction.
* \param checker a pointer to an AttributeChecker which can verify
* that any user-supplied value to override the initial
* value matches the requested type constraints.
*/
GlobalValue (std::string name, std::string help,
const AttributeValue &initialValue,
Ptr<const AttributeChecker> checker);
/**
* \returns the name of this GlobalValue.
*/
std::string GetName (void) const;
/**
* \returns the help text of this GlobalValue.
*/
std::string GetHelp (void) const;
/**
* \returns the current value of this GlobalValue.
*/
void GetValue (AttributeValue &value) const;
/**
* \returns the checker associated to this GlobalValue.
*/
Ptr<const AttributeChecker> GetChecker (void) const;
/**
* \param value the new value to set in this GlobalValue.
*/
bool SetValue (const AttributeValue &value);
/**
* \param name the name of the global value
* \param value the value to set in the requested global value.
*
* Iterate over the set of GlobalValues until a matching name is found
* and then set its value with GlobalValue::SetValue.
*
* This method cannot fail. It will crash if the input is not valid.
*/
static void Bind (std::string name, const AttributeValue &value);
/**
* \param name the name of the global value
* \param value the value to set in the requested global value.
* \returns true if the value could be set successfully, false otherwise.
*
* Iterate over the set of GlobalValues until a matching name is found
* and then set its value with GlobalValue::SetValue.
*/
static bool BindFailSafe (std::string name, const AttributeValue &value);
/**
* \returns an iterator which represents a pointer to the first GlobalValue registered.
*/
static Iterator Begin (void);
/**
* \returns an iterator which represents a pointer to the last GlobalValue registered.
*/
static Iterator End (void);
private:
friend class GlobalValueTests;
static Vector *GetVector (void);
void InitializeFromEnv (void);
std::string m_name;
std::string m_help;
Ptr<AttributeValue> m_initialValue;
Ptr<const AttributeChecker> m_checker;
};
} // namespace ns3
#endif /* GLOBAL_VALUE_H */