foam-framework/js/foam/dao/FutureDAO.js

MVC metaprogramming framework

/**
 * @license
 * Copyright 2014 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

CLASS({
  package: 'foam.dao',
  name: 'FutureDAO',
  extends: 'foam.dao.ProxyDAO',

  documentation: function() {/*
    A DAO proxy that delays operations until the delegate is set in the future.
  */ },

  properties: [
    {
      name: 'delegate',
      factory: function() { return null; }
    },
    {
      name: 'future',
      required: true,
      documentation: "The future on which to operate before the delegate becomes available."
    },
    {
      name: 'model',
      defaultValueFn: function() { return this.delegate ? this.delegate.model : ''; },
      documentation: function() {/*
        The model type of the items in the delegate DAO. Empty if the future has not been set yet.
      */}
    }
  ],

  methods: {
    init: function() { /* Sets up the future to provide us with the delegate when it becomes available. */
      this.SUPER();

      this.future(function(delegate) {
        var listeners = this.daoListeners_;
        this.daoListeners_ = [];
        this.delegate = delegate;
        this.daoListeners_ = listeners;
      }.bind(this));
    },

    put: function(value, sink) { /* Passthrough to delegate or the future, if delegate not set yet. */
      if ( this.delegate ) {
        this.delegate.put(value, sink);
      } else {
        this.future(this.put.bind(this, value, sink));
      }
    },

    remove: function(query, sink) { /* Passthrough to delegate or the future, if delegate not set yet. */
      if ( this.delegate ) {
        this.delegate.remove(query, sink);
      } else {
        this.future(this.remove.bind(this, query, sink));
      }
    },

    removeAll: function() { /* Passthrough to delegate or the future, if delegate not set yet. */
      if ( this.delegate ) {
        return this.delegate.removeAll.apply(this.delegate, arguments);
      }

      var a = arguments;
      var f = afuture();
      this.future(function(delegate) {
        this.removeAll.apply(this, a)(f.set);
      }.bind(this));

      return f.get;
    },

    find: function(key, sink) {/* Passthrough to delegate or the future, if delegate not set yet. */
      if ( this.delegate ) {
        this.delegate.find(key, sink);
      } else {
        this.future(this.find.bind(this, key, sink));
      }
    },

    select: function(sink, options) {/* Passthrough to delegate or the future, if delegate not set yet. */
      if ( this.delegate ) {
        return this.delegate.select(sink, options);
      }

      var a = arguments;
      var f = afuture();
      this.future(function() {
        this.select.apply(this, a)(f.set);
      }.bind(this));

      return f.get;
    },
  }
});