# ActiveObject

Inspired by ActiveModel for Rails, ActiveObject provides functionality to easily validate and merge JSON documents.

## Installation

    $ npm install activeobject
  
## Features
  * Attribute Accessible
  * Validations
  * hasOne
  * hasMany
  * Normalization
  
## Using ActiveObject

ActiveObject takes an object defining the properties of the class to create, and returns a constructor for that class.

    var ActiveObject = require("active-object");
    var Foo = ActiveObject({});
    
## Defining Attributes  

    var Rectangle = ActiveObject({
      attributeAccessible: ["height", "width"]
    });
    
    var square = new Rectangle();
    square.height = 5;
    square.width = 5;

Once an object is created, it will only accept assignment of properties defined in attributeAccessible

    square.radius = 10;
    // => Error!

Properties can also be set when creating the object:

    var square = new Rectangle({ height: 5, width: 5 });
    
Or they can be set together:

    var square = new Rectangle();
    square.attributes = { height: 5, width: 5 };
    
Again, setting a property not defined in the attributeAccessible will result in an error:

    var square = new Rectangle({ radius: 10 });
    // => Error
    
    var square = new Rectangle();
    square.attributes = { radius: 10 };
    // => Error
  
## Defining Child Objects

  ActiveObject provides 2 ways to define child objects, hasOne and hasMany

### hasOne
hasOne relationships can be defined with an object using the key as the property name, and the constructor as the value.

    var Star = ActiveObject({
      attributeAccessible: ["diameter"]
    });
    
    var SolarSystem = ActiveObjct({
      hasOne: { sun: Star }
    });
    
The object can then have its child set the same as a regular attribute:

    var solarSystem = new SolarSystem();
    solarSystem.sun = new Star({diameter: "1,392,000 Km"});
    
    solarSystem.sun.diamaeter;
    // => 1,392,000 Km
  
### hasMany
hasMany relationships are defined the same as hasOne relationships. 

    var Star = ActiveObject({
      attributeAccessible: ["diameter"]
    });
  
    var SolarSystem = ActiveObjct({
      hasOne: { sun: Star },
      hasMany: { planets: Planet }
    });
  
    var Planet = ActiveObject({
      attributeAccessible: ["name"]
    });
  
A SolarSystem can now have 1 star and many planets.

    var solarSystem = new SolarSystem();
    solarSystem.sun = new Star({diameter: "1,392,000 Km"});
    
    solarSystem.planets.build({ name: "Mercury"});
    solarSystem.planets.build({ name:"Venus"});
    solarSystem.planets.build({ name:"Earth"})
    solarSystem.planets.build({ name:"Mars"});
    solarSystem.planets.build({ name:"Jupiter"});
    solarSystem.planets.build({ name:"Saturn"});
    solarSystem.planets.build({ name:"Uranus"});
  
    forEach(solarSystem.planets, function(planet) {
      console.log(planet.name);
    });
    
    // => "Mercury"
    // => "Venus"
    // => "Earth"
    // => "Mars"
    // => "Jupiter"
    // => "Saturn"
    // => "Uranus"
  
### hasMany Collection Methods
ActiveObject adds the following methods for retrieval and query to collections:

#### collection.findById(id)
Finds an associated object responding to the id and that meets the condition that it has to be associated with this object.

#### collection.build(attributes = {})
Returns a new object of the collection type that has been instantiated with attributes and added to this objects collection.

## License 

(The MIT License)

Copyright (c) 2009-2011 Mike Hemesath <mike.hemesath@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.