[model][m]: (fixes #6) create a BackendMemory (local data in memory) and refactor code to use this rather than current hard-coding-of-data approach.

src/model.js

@@ -2,9 +2,7 @@ this.recline = this.recline || {};
 
 // A Dataset model.
 recline.Dataset = Backbone.Model.extend({
-  initialize: function(data, rawDocumentSet) {
-    this.documentSet = new recline.DocumentSet(rawDocumentSet);
-  }
+  __type__: 'Dataset'
 });
 
 recline.Document = Backbone.Model.extend({});
@@ -15,9 +13,7 @@ recline.DocumentList = Backbone.Collection.extend({
 })
 
 recline.DocumentSet = Backbone.Model.extend({
-  fetch: function(options) {
-    options.success(this);
-  },
+  __type__: 'DocumentSet',
   getLength: function() { 
     return this.get('rows').length;
   },
@@ -35,3 +31,46 @@ recline.DocumentSet = Backbone.Model.extend({
   }
 });
 
+// Backend which just caches in memory
+// 
+// Does not need to be a backbone model but provides some conveience
+recline.BackendMemory = Backbone.Model.extend({
+  initialize: function() {
+    this._datasetCache = {}
+  }, 
+  // dataset is object with metadata and data attributes
+  addDataset: function(dataset) {
+    this._datasetCache[dataset.metadata.id] = dataset;
+  },
+  getDataset: function(id) {
+    var dataset = new recline.Dataset({
+      id: id
+    });
+    // this is a bit weird but problem is in sync this is set to parent model object so need to give dataset a reference to backend explicitly
+    dataset.backend = this;
+    return dataset;
+  },
+  sync: function(method, model, options) {
+    if (method === "read") {
+      var dfd = $.Deferred();
+      // this switching on object type is rather horrible
+      // think may make more sense to do work in individual objects rather than in central Backbone.sync
+      if (this.__type__ == 'Dataset') {
+        var dataset = this;
+        var rawDataset = this.backend._datasetCache[model.id];
+        dataset.set(rawDataset.metadata);
+        dataset.documentSet = new recline.DocumentSet(rawDataset.data);
+        dataset.documentSet.dataset = dataset;
+        dfd.resolve(dataset);
+      } else if (this.__type__ == 'DocumentSet') {
+        dfd.resolve(this);
+      }
+      return dfd.promise();
+    }
+  }
+});
+
+recline.setBackend = function(backend) {
+  Backbone.sync = backend.sync;
+};
+