content: /* Copyright 2010, Object Management Group, Inc.
   * Copyright 2010, PrismTech, Inc.
   * Copyright 2010, Real-Time Innovations, Inc.
   * All rights reserved.
   *
   * 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.omg.dds.core.status;
  
  import org.omg.dds.core.InstanceHandle;
  
  
  /**
   * The liveliness of one or more {@link org.omg.dds.pub.DataWriter}s that were writing
   * instances read through the {@link org.omg.dds.sub.DataReader} has changed. Some
   * DataWriter(s) have become "active" or "inactive."
   *
   * @see org.omg.dds.core.event.LivelinessChangedEvent
   * @see LivelinessLostStatus
   */
  public abstract class LivelinessChangedStatus extends Status
  {
      // -----------------------------------------------------------------------
      // Constants
      // -----------------------------------------------------------------------
  
      private static final long serialVersionUID = -8771335633962700621L;
  
  
  
      // -----------------------------------------------------------------------
      // Methods
      // -----------------------------------------------------------------------
  
      /**
       * The total number of currently active {@link org.omg.dds.pub.DataWriter}s that write
       * the Topic read by the {@link org.omg.dds.sub.DataReader}. This count increases when a
       * newly matched DataWriter asserts its liveliness for the first time or
       * when a DataWriter previously considered to be not alive reasserts its
       * liveliness. The count decreases when a DataWriter considered alive
       * fails to assert its liveliness and becomes not alive, whether because
       * it was deleted normally or for some other reason.
       */
      public abstract int getAliveCount();
  
      /**
       * The total count of currently {@link org.omg.dds.pub.DataWriter}s that write the
       * {@link org.omg.dds.topic.Topic} read by the {@link org.omg.dds.sub.DataReader} that are no longer
       * asserting their liveliness. This count increases when a DataWriter
       * considered alive fails to assert its liveliness and becomes not alive
       * for some reason other than the normal deletion of that DataWriter.
       * It decreases when a previously not alive DataWriter either reasserts
       * its liveliness or is deleted normally.
       */
      public abstract int getNotAliveCount();
  
      /**
       * The change in the aliveCount since the last time the listener was
       * called or the status was read.
       */
      public abstract int getAliveCountChange();
  
      /**
       * The change in the notAliveCount since the last time the listener was
       * called or the status was read.
       */
      public abstract int getNotAliveCountChange();
  
      /**
       * Handle to the last {@link org.omg.dds.pub.DataWriter} whose change in liveliness
       * caused this status to change.
       * contains the instance handle to the {@link org.omg.dds.topic.PublicationBuiltinTopicData} instance that represents the last
       * {@link org.omg.dds.pub.DataWriter} whose change in liveliness caused this status to change.
       * Be aware that this handle belongs to another datareader, the PublicationBuiltinTopicDataDataReader
       * in the builtin-subscriber, and has no meaning in the context of the datareader from which the
       * LivelinessChangedStatus was obtained. If the builtin-subscriber has not explicitly been obtained using
       * get_builtin_subscriber on the DomainParticipant, then there is no PublicationBuiltinTopicDataDataReader as well,
       * in which case the last_publication_handle will be set to HANDLE_NIL.
       */
      public abstract InstanceHandle getLastPublicationHandle();
  }
  