src/main/java/org/apache/aurora/scheduler/updater/InstanceStateProvider.java

/**
 * 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.
 */
package org.apache.aurora.scheduler.updater;

/**
 * Provider that fetches the state associated with an instance ID.
 *
 * @param <K> The identifier type for instances.
 * @param <T> Instance data type.
 */
interface InstanceStateProvider<K, T> {

  /**
   * Fetches the latest state for an instance.
   *
   * @param instanceId Instance identifier.
   * @return Data associated with {@code instanceId}.
   */
  T getState(K instanceId);
}