creer-une-structure.md

description
Structures represent the schema of a collection, containing its fields and types

Create Structure

{% hint style="info" %} Information: this is a simple class to create, which must extend the class Element {% endhint %}

{% hint style="info" %} Information: the class can contain fields of type derived from Element {% endhint %}

{% hint style="danger" %} Warning: The class must not have a defined constructor, or the constructor must not have an argument, since the instantiation is done by reflection. {% endhint %}

Examples

public static class VillageScore extends Element {
    public int security;
    public int livingComfort;
    public int decoration;
}

public static class Village extends Element {
    @Required
    @Index(unique = true, type = Index.Type.SINGLE)
    public String name;
    public int members;
    public VillageScore score = new VillageScore(); // must be instancied !!
}

Features:

The class:

• It must be independent. If not, it must be static.
• It must necessarily extend Element.
• It must not have a constructor, except the default constructor with no arguments.

The fields:

• They can contain default values ​​if necessary.
• They can be of structure class type, for sub-documents, it will be necessary to manually instantiate a new instance to define the value of this field.
• The field _id already exists, in restricted scope.

Field annotations:

• The @Required annotation allows to require a defined value, otherwise an error will be caused.
• The @Index annotation makes it possible to require indexing on the database side, it will create the index if it does not exist.
• The unique parameter makes it possible to force the unique value for the field at the database level, but also at the library level by causing an error.
• The type parameter is used to define the type of index.

Les méthodes

• Vous pouvez bien sûr créer les méthodes que vous souhaitez, quelque soit l'action qu'elles font, elles peuvent lire ou écrire des fields sans problème.