foam-framework/js/foam/core/dao/MergeDAO.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.core.dao',
  name: 'MergeDAO',
  extends: 'foam.dao.ProxyDAO',

  properties: [
    {
      model_: 'FunctionProperty',
      name: 'mergeStrategy',
      required: true
    }
  ],

  methods: {
    put: function(obj, sink) {
      var self = this;
      this.delegate.find(obj.id, {
        put: function(oldValue) {
          aseq(
            function(ret) {
              self.mergeStrategy(ret, oldValue, obj);
            },
            function(ret, obj) {
              self.delegate.put(obj, sink);
            })();
        },
        error: function() {
          // TODO: Distinguish internal versus external errors.
          self.delegate.put(obj, sink);
        }
      });
    }
  }
});