configmaps.md

Config Maps {#configmaps}

Overview

The ConfigMap is a nested implementation of std::maps and std::vectors to provide a python dictionary-like data storage structure. Datatypes that can be stored are:

• std::string
• int
• unsigned int
• unsinged long
• double
• bool

An important feature is the loading and storing of ConfigMaps in yaml files. The example shows the usage of ConfigMaps for further details check [ConfigMap](@ref mars::utils::ConfigData.h).

Note: While reading and writing yaml files the order of dictionaries is not necessarily kept.

Yaml example file:

    list: [1, 2, a, b]
    name: foo
    value1: 1.3
    value2: 1
    foo:
        foo2: Hello world!
        foo3: blub

Example program:

    #include <configmaps/ConfigMap.hpp>
    #include <configmaps/ConfigVector.hpp>

    int main(int argc, char *argv[]) {

      // some ConfigMap test
      configmaps::ConfigMap map;
      map = configmaps::ConfigMap::fromYamlFile("test.yml");
      configmaps::ConfigVector::iterator it;
      for(it=map["list"].begin(); it!=map["list"].end(); ++it) {
        printf("list entry: %s\n", it->c_str());
      }
      double value1 = map["value1"];
      printf("value1: %g\n", value1);
      int value2 =  map["value2"];
      printf("value2: %d\n", value2);
      map["value2"] = 3;
      printf("value2 modified: %d\n", value2);

      std::string foo2 = map["foo"]["foo2"];
      std::string foo3 = map["foo"][0]["foo3"];

      printf("%s\n", foo2.c_str());
      printf("%s\n", foo3.c_str());

      // add some keys:
      map["value3"] = 3.14;
      printf("value3: %g\n", (double)map["value3"]);

      map["blub"]["foo"] = "3.14";
      printf("blub/foo: %g\n", (double)map["blub"]["foo"]);


      // if map contains the key "da" the map value is returned
      // otherwise the second argument is returned
      long unsigned da = map.get("da", 0lu);

      // if map contains the key "da2" the map value is returned
      // otherwise the second argument is added to the map and returned
      // afterwards
      long unsigned da2 = map.getOrCreate("da2", 0lu);

      map.toYamlFile("result.yml");

      return 0;
    }

result.yml:

    foo:
      foo2: Hello world!
      foo3: blub
    list:
      - 1
      - 2
      - a
      - b
    name: foo
    value1: 1.3
    value2: 3
    value3: 3.14
    blub:
      foo: 3.14

more syntax examples:

     double inputs[4] = {1, 2, 3, 4};
     for(int i=0; i<4; ++i) {
       for(int n=0; n<4; ++n) {
         map["unit_tests"][i]["inputs"] << inputs[n];
       }
     }

ConfigSchema example: Schema:

name:
  type: string
weight:
  type: number
age:
  type: integer
  minimum: 18
  maximum: 60
verified: 
  type: boolean
contact:
    type: object
    properties:
      phone:
        type: string
      email: 
        type: string                                                                                                         
nicknames:
  type: array
  contains:
    type: string

Config:

name: Angel
weight: 56.33
age: 23
verified: true
contact:
  phone: "0171140123"
  email: "[email protected]"
nicknames:
  - santa
  - angie

Usage:

ConfigSchema cs(schema);
bool isValid = cs.validate(config);

[26.08.2014]