mediawiki-extensions-Visual.../modules/ve/ve.Factory.js

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/**
* Generic object factory.
*
* @class
* @abstract
* @constructor
* @extends {ve.EventEmitter}
*/
ve.Factory = function() {
// Inheritance
ve.EventEmitter.call( this );
// Properties
this.registry = [];
};
/* Methods */
/**
* Register a constructor with the factory.
*
* Arguments will be passed through directly to the constructor.
* @see {ve.Factory.prototype.create}
*
* @method
* @param {String} type Object type
* @param {Function} constructor Constructor to use when creating object
* @throws 'Constructor must be a function, cannot be a string'
*/
ve.Factory.prototype.register = function( type, constructor ) {
if ( typeof constructor !== 'function' ) {
throw 'Constructor must be a function, cannot be a ' + typeof constructor;
}
this.registry[type] = constructor;
this.emit( 'register', type, constructor );
};
/**
* Create an object based on a type.
*
* Type is used to look up the constructor to use, while all additional arguments are passed to the
* constructor directly, so leaving one out will pass an undefined to the constructor.
*
* WARNING: JavaScript does not allow using new and .apply together, so we just pass through 2
* arguments here since we know we only need that many at this time. If we need more in the future
* we should change this to suit that use case. Because of undefined pass through, there's no harm
* in adding more.
*
* @method
* @param {String} type Object type
* @param {Mixed} [...] Up to 2 additional arguments to pass through to the constructor
* @returns {Object} The new object
* @throws 'Unknown object type'
*/
ve.Factory.prototype.create = function( type, a, b ) {
if ( type in this.registry ) {
return new this.registry[type]( a, b );
}
throw 'Unknown object type: ' + type;
};
/**
* Gets a constructor for a given type.
*
* @method
* @param {String} type Object type
* @returns {Function|undefined} Constructor for type
*/
ve.Factory.prototype.lookup = function( type ) {
return this.registry[type];
};
/* Inheritance */
ve.extendClass( ve.Factory, ve.EventEmitter );