Command_Exercise.cpp

Go to the documentation of this file.

 
 
#include <iostream>
#include <sstream>
#include <vector>
 
#include "Command_Exercise.h"
#include "Command_Classes.h"
 
#include "helpers/formatstring.h"
#include "helpers/replace.h"
 
namespace // Anonymous
{
    using namespace DesignPatternExamples_cpp;
 
    std::vector<Command> _commandUndoList;
 
    void Command_Save_And_Execute(Command command)
    {
        _commandUndoList.push_back(command);
        command.Execute();
    }
 
    static void Command_Operation_Replace(Command_TextObject::shared_ptr_t source, std::string searchPattern, std::string replaceText)
    {
        std::string newText = Helpers::Replace(source->Text(), searchPattern.c_str(), replaceText.c_str());
        source->SetText(newText);
    }
 
    static void Command_Operation_Reverse(Command_TextObject::shared_ptr_t source)
    {
        std::ostringstream output;
        std::string text = source->Text();
        for (size_t index = 0; index < text.size(); ++index)
        {
            output << text[text.size() - 1 - index];
        }
        source->SetText(output.str());
    }
 
    void Command_Undo(Command_TextObject::shared_ptr_t text)
    {
        if (!_commandUndoList.empty())
        {
            // Reset the text to the starting point.
            text->Reset();
 
            // Get rid of the last command applied and remember it.
            Command lastCommand = _commandUndoList.back();
            _commandUndoList.pop_back();
 
            // Now apply all remaining commands to the text in order
            // (oldest to newest).
            std::vector<Command>::iterator commandIter = std::begin(_commandUndoList);
            while (commandIter != std::end(_commandUndoList))
            {
                (*commandIter).Execute();
                commandIter++;
            }
 
            // Show off what we (un)did.
            std::cout << Helpers::formatstring("    undoing command %-31s==> \"%s\"",
                lastCommand.ToString().c_str(), text->ToString().c_str()) << std::endl;
        }
    }
 
    void Command_ApplyReplaceCommand(Command_TextObject::shared_ptr_t text, std::string searchPattern, std::string replaceText)
    {
        Command command(text, "Replace", Command_Operation_Replace, searchPattern, replaceText);
        Command_Save_And_Execute(command);
        std::cout << Helpers::formatstring("    command %-31s==> \"%s\"",
            command.ToString().c_str(), text->ToString().c_str()) << std::endl;
    }
 
 
    void Command_ApplyReverseCommand(Command_TextObject::shared_ptr_t text)
    {
        Command command(text, "Reverse", Command_Operation_Reverse);
        Command_Save_And_Execute(command);
        std::cout << Helpers::formatstring("    command %-31s==> \"%s\"",
            command.ToString().c_str(), text->ToString().c_str()) << std::endl;
    }
 
} // end anonymous namespace
 
namespace DesignPatternExamples_cpp
{
 
    // ! [Using Command in C++]
    void Command_Exercise()
    {
        std::cout << std::endl;
        std::cout << "Command Exercise" << std::endl;
 
        // The base text object to work from.
        Command_TextObject::shared_ptr_t text = std::make_shared<Command_TextObject>("This is a line of text on which to experiment.");
 
        std::cout << Helpers::formatstring("  Starting text: \"%s\"", text->ToString().c_str()) << std::endl;
 
        // Apply four operations to the text.
        Command_ApplyReplaceCommand(text, "text", "painting");
        Command_ApplyReplaceCommand(text, "on", "off");
        Command_ApplyReverseCommand(text);
        Command_ApplyReplaceCommand(text, "i", "!");
 
        std::cout << "  Now perform undo until back to original" << std::endl;
 
        // Now undo the four operations.
        Command_Undo(text);
        Command_Undo(text);
        Command_Undo(text);
        Command_Undo(text);
 
        std::cout << Helpers::formatstring("  Final text   : \"%s\"", text->ToString().c_str()) << std::endl;
 
        std::cout << "  Done." << std::endl;
    }
    // ! [Using Command in C++]
 
 
} // end namespace