/*
 * Copyright 2010 The Apache Software Foundation
 *
 * 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.hadoop.hbase.ipc;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.hbase.security.User;

/**
 * The IPC connection header sent by the client to the server
 * on connection establishment.
 */
class ConnectionHeader implements Writable {
  protected String protocol;

  public ConnectionHeader() {}

  /**
   * Create a new {@link ConnectionHeader} with the given <code>protocol</code>
   * and {@link User}.
   * @param protocol protocol used for communication between the IPC client
   *                 and the server
   * @param user {@link User} of the client communicating with
   *            the server
   */
  public ConnectionHeader(String protocol, User user) {
    this.protocol = protocol;
  }

  @Override
  public void readFields(DataInput in) throws IOException {
    protocol = Text.readString(in);
    if (protocol.isEmpty()) {
      protocol = null;
    }
  }

  @Override
  public void write(DataOutput out) throws IOException {
    Text.writeString(out, (protocol == null) ? "" : protocol);
  }

  public String getProtocol() {
    return protocol;
  }

  public User getUser() {
    return null;
  }

  public String toString() {
    return protocol;
  }
}