AbstractGroupMember.java

/*
 * Copyright 2016 the original author or authors.
 *
 * 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 io.atomix.group.internal;

import io.atomix.catalyst.concurrent.Listener;
import io.atomix.catalyst.concurrent.Listeners;
import io.atomix.catalyst.util.Assert;
import io.atomix.group.GroupMember;
import io.atomix.group.messaging.internal.AbstractMessageClient;

import java.util.Optional;
import java.util.function.Consumer;

/**
 * Abstract group member.
 *
 * @author <a href="http://github.com/kuujo>Jordan Halterman</a>
 */
public abstract class AbstractGroupMember implements GroupMember {
  protected final String memberId;
  protected final MembershipGroup group;
  protected final Object metadata;
  protected volatile Status status = Status.ALIVE;
  protected final Listeners<Status> statusListeners = new Listeners<>();

  public AbstractGroupMember(GroupMemberInfo info, MembershipGroup group) {
    this.memberId = info.memberId();
    this.group = Assert.notNull(group, "group");
    this.metadata = info.metadata();
  }

  @Override
  public String id() {
    return memberId;
  }

  @Override
  public Status status() {
    return status;
  }

  /**
   * Called when a status change event is received for the member.
   */
  void onStatusChange(Status status) {
    if (this.status != status) {
      this.status = status;
      statusListeners.accept(status);
    }
  }

  @Override
  public Listener<Status> onStatusChange(Consumer<Status> callback) {
    return statusListeners.add(callback);
  }

  @Override
  public abstract AbstractMessageClient messaging();

  @SuppressWarnings("unchecked")
  public <T> Optional<T> metadata() {
    return metadata == null
        ? Optional.empty()
        : Optional.of((T) metadata);
  }

}