JobCatalogListenersContainer.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 gobblin.runtime.api;

/**
 * Manages a collection of {@link JobCatalogListener}s .
 */
public interface JobCatalogListenersContainer {

  /**
   * Adds a {@link JobCatalogListener} that will be invoked upon updates on the
   * {@link JobCatalog}. Upon registration {@link JobCatalogListener#onAddJob(JobSpec)} will be
   * invoked for all pre-existing jobs in the JobCatalog.
   */
  void addListener(JobCatalogListener jobListener);

  /**
   * Like {@link #addListener(JobCatalogListener)} but it will create a weak reference. The
   * implementation will automatically remove the listener registration once the listener object
   * gets GCed.
   *
   * <p>Note that weak listeners cannot be removed using {@link #removeListener(JobCatalogListener)}.
   */
  void registerWeakJobCatalogListener(JobCatalogListener jobListener);

  /**
   * Removes the specified listener. No-op if not registered.
   */
  void removeListener(JobCatalogListener jobListener);

}