geode-core/src/main/java/org/apache/geode/cache/client/internal/Connection.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 org.apache.geode.cache.client.internal;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.SocketException;
import java.nio.ByteBuffer;

import org.apache.geode.InternalGemFireException;
import org.apache.geode.distributed.internal.ServerLocation;
import org.apache.geode.internal.cache.tier.sockets.ServerQueueStatus;

/**
 * Represents a connection from a client to a server. Instances are created, kept, and used by
 * {@link PoolImpl}.
 *
 * @since GemFire 5.7
 */
public interface Connection {
  long DEFAULT_CONNECTION_ID = 26739;

  Socket getSocket();

  ByteBuffer getCommBuffer() throws SocketException;

  ConnectionStats getStats();

  /**
   * Forcefully close the resources used by this connection. This should be called if the connection
   * or the server dies.
   */
  void destroy();

  /**
   * Return true if this connection has been destroyed
   */
  boolean isDestroyed();

  /**
   * Gracefully close the connection by notifying the server. It is not necessary to call destroy
   * after closing the connection.
   *
   * @param keepAlive What do do this server to client connection proxy on this server.
   * @throws Exception if there was an error notifying the server. The connection will still be
   *         destroyed.
   */
  void close(boolean keepAlive) throws Exception;

  ServerLocation getServer();

  Endpoint getEndpoint();

  ServerQueueStatus getQueueStatus();

  Object execute(Op op) throws Exception;

  void emergencyClose();

  short getWanSiteVersion();

  void setWanSiteVersion(short wanSiteVersion);

  int getDistributedSystemId();

  OutputStream getOutputStream();

  InputStream getInputStream();

  void setConnectionID(long id);

  long getConnectionID();

  /**
   * If this connection wraps another connection then
   * return the wrapped connection.
   * If this connection does not wrap then return this.
   *
   * @return the wrapped connection or this connection
   * @throws ConnectionDestroyedException if the wrapped connection no longer exists
   */
  default Connection getWrappedConnection() {
    return this;
  }

  /**
   * Mark the connection as being actively used.
   *
   * @return true if connection activated, false if could not be activated because it is destroyed
   * @throws InternalGemFireException when the connection is already active
   */
  default boolean activate() {
    return true;
  }

  /**
   * Mark the connection as one that is not being used.
   *
   * @param accessed true if the connection was used while active
   * @throws InternalGemFireException when the connection is already passive
   */
  default void passivate(boolean accessed) {}
}