Persistence.java

/**
 * Copyright 2016 Google Inc.
 *
 * <p>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
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.
 */
package com.example.guestbook;

import com.google.cloud.datastore.Datastore;
import com.google.cloud.datastore.DatastoreOptions;
import com.google.cloud.datastore.KeyFactory;

import java.util.concurrent.atomic.AtomicReference;

//[START all]
public class Persistence {
  private static AtomicReference<Datastore> datastore = new AtomicReference<>();

  public static Datastore getDatastore() {
    if (datastore.get() == null) {
      datastore.set(DatastoreOptions.newBuilder().setProjectId("your-project-id-here")
          .build().getService());
    }

    return datastore.get();
  }

  public static void setDatastore(Datastore datastore) {
    Persistence.datastore.set(datastore);
  }

  public static KeyFactory getKeyFactory(Class<?> c) {
    return getDatastore().newKeyFactory().setKind(c.getSimpleName());
  }
}
//[END all]