Add DatastoreDB.replace({defaultPartition})

lib/src/db/db.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of gcloud.db;
 
 /**
  * A function definition for transactional functions.
  *
  * The function will be given a [Transaction] object which can be used to make
@@ skipping 229 matching lines @@
     }
     return propertyName;
   }
 }
 
 class DatastoreDB {
   final datastore.Datastore datastore;
   final ModelDB _modelDB;
   Partition _defaultPartition;
 
-  DatastoreDB(this.datastore, {ModelDB modelDB})
-      : _modelDB = modelDB != null ? modelDB : new ModelDBImpl() {
-    _defaultPartition = new Partition(null);
+  DatastoreDB(this.datastore, {ModelDB modelDB, Partition defaultPartition}) :
+      _modelDB = modelDB != null ? modelDB : new ModelDBImpl() {
+      _defaultPartition =
+          defaultPartition != null ? defaultPartition : new Partition(null);
   }
 
   /**
    * The [ModelDB] used to serialize/deserialize objects.
    */
   ModelDB get modelDB => _modelDB;
 
   /**
    * Gets the empty key using the default [Partition].
    *
@@ skipping 55 matching lines @@
    * The order of inserts and deletes is not specified. When the commit is done
    * direct lookups will see the effect but non-ancestor queries will see the
    * change in an eventual consistent way.
    *
    * For transactions, please use `beginTransaction` and it's returned
    * [Transaction] object.
    */
   Future commit({List<Model> inserts, List<Key> deletes}) {
     return _commitHelper(this, inserts: inserts, deletes: deletes);
   }
+
+  /**
+   * Returns a new [DatastoreDB] with the given [defaultPartition].
+   */
+  DatastoreDB replace({Partition defaultPartition}) {

[Søren Gjesse, 2015/02/19 11:59:51]

The method name 'replace' seems somewhat overloaded with operation you would
expect on a DatastoreDB instance. How about changing this to a DatastoreDB.from
constructor?

var existingDb = ...
var otherDb = new DatastoreDB.from(existingDb, defaultPartition: ...);

[kustermann, 2015/02/19 12:17:11]

Another constructor is of no value, since the existing one can do that as well.

Removed replace method now.

+    return new DatastoreDB(
+        datastore, modelDB: modelDB, defaultPartition: defaultPartition);
+  }
 }
 
 Future _commitHelper(DatastoreDB db,
                      {List<Model> inserts,
                       List<Key> deletes,
                       datastore.Transaction datastoreTransaction}) {
   var entityInserts, entityAutoIdInserts, entityDeletes;
   var autoIdModelInserts;
   if (inserts != null) {
     entityInserts = [];
@@ skipping 35 matching lines @@
 
 Future<List<Model>> _lookupHelper(
     DatastoreDB db, List<Key> keys,
     {datastore.Transaction datastoreTransaction}) {
   var entityKeys = keys.map(db.modelDB.toDatastoreKey).toList();
   return db.datastore.lookup(entityKeys, transaction: datastoreTransaction)
       .then((List<datastore.Entity> entities) {
     return entities.map(db.modelDB.fromDatastoreEntity).toList();
   });
 }