RegisterEntry.java

/*
 * Copyright 2015 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.copycat.server.storage.entry;

import io.atomix.catalyst.buffer.BufferInput;
import io.atomix.catalyst.buffer.BufferOutput;
import io.atomix.catalyst.serializer.Serializer;
import io.atomix.catalyst.util.Assert;
import io.atomix.catalyst.util.reference.ReferenceManager;
import io.atomix.copycat.protocol.RegisterRequest;

/**
 * Stores a client register request.
 * <p>
 * The {@code RegisterEntry} is stored and replicated when a client submits a
 * {@link RegisterRequest} to the cluster to register a new session.
 * Session registrations are replicated and applied on all state machines to ensure each server state
 * machine has a consistent view of the sessions in the cluster, and registration entries are not
 * removed from the underlying log until the session itself has been expired or closed.
 *
 * @author <a href="http://github.com/kuujo">Jordan Halterman</a>
 */
public class RegisterEntry extends TimestampedEntry<RegisterEntry> {
  private String client;
  private long timeout;

  public RegisterEntry() {
  }

  public RegisterEntry(ReferenceManager<Entry<?>> referenceManager) {
    super(referenceManager);
  }

  /**
   * Returns the entry client ID.
   *
   * @return The entry client ID.
   */
  public String getClient() {
    return client;
  }

  /**
   * Sets the entry client ID.
   *
   * @param client The entry client ID.
   * @return The register entry.
   * @throws NullPointerException if {@code client} is null
   */
  public RegisterEntry setClient(String client) {
    this.client = Assert.notNull(client, "client");
    return this;
  }

  /**
   * Returns the session timeout.
   *
   * @return The session timeout.
   */
  public long getTimeout() {
    return timeout;
  }

  /**
   * Sets the session timeout.
   *
   * @param timeout The session timeout.
   * @return The register entry.
   */
  public RegisterEntry setTimeout(long timeout) {
    this.timeout = Assert.argNot(timeout, timeout <= 0, "timeout must be positive");
    return this;
  }

  @Override
  public void writeObject(BufferOutput buffer, Serializer serializer) {
    super.writeObject(buffer, serializer);
    buffer.writeString(client);
    buffer.writeLong(timeout);
  }

  @Override
  public void readObject(BufferInput buffer, Serializer serializer) {
    super.readObject(buffer, serializer);
    client = buffer.readString();
    timeout = buffer.readLong();
  }

  @Override
  public String toString() {
    return String.format("%s[index=%d, term=%d, client=%s, timeout=%d]", getClass().getSimpleName(), getIndex(), getTerm(), getClient(), getTimestamp());
  }

}