PlaceholderExpression.hpp

//
//  Copyright PHOENIX CONTACT Electronics GmbH
//
#pragma once
#include "Arp/System/Core/Arp.h"
#include "Arp/System/Commons/Exceptions/Exceptions.h"
#include "Arp/System/Commons/Environment.hpp"
#include <sstream>

namespace Arp { namespace System { namespace Commons { namespace Configuration
{

class PlaceholderExpression
{
public: // typedefs

public: // construction/destruction
    PlaceholderExpression(void) = default;
    PlaceholderExpression(const PlaceholderExpression& arg) = default;
    PlaceholderExpression& operator=(const PlaceholderExpression& arg) = default;
    ~PlaceholderExpression(void) = default;

public: // operators

public: // static operations
    static bool HasPlaceholder(const String& input, const String& placeholder);
    static bool HasPlaceholder(const String& input);
    static bool HasLogicalExpression(const String& input);

public: // setter/getter operations

public: // operations
    String  Resolve(const String& input);
    bool    TryResolve(const String& input, String& result);
    bool    ResolveCondition(const String& input);
    String  ResolveLogicalExpression(const String& input);

    template<class T>
    T       ResolveTo(const String& input);

protected: // operations

private: // static methods

private: // methods
    static bool HasLogicalExpression(const std::string& input);

private: // fields

private: // static fields
    static const String envVarSeperator;
};

// inline methods of class PlaceholderExpression

inline bool PlaceholderExpression::HasLogicalExpression(const String& input)
{
    return PlaceholderExpression::HasLogicalExpression(input.GetBaseString());
}

template<class T>
inline T PlaceholderExpression::ResolveTo(const String& input)
{
    if (input.IsEmpty())
    {
        throw ArgumentException("Input is empty.");
    }
    // else
    std::istringstream iss(this->Resolve(input));
    T result;
    iss >> std::boolalpha >> result;
    if (iss.fail())
    {
        throw ArgumentException("Input is not of required type.");
    }
    // else
    return result;
}

}}}} // end of namespace Arp::System::Commons::Configuration