ServiceClientHandshake.java

/*
 * Copyright (C) 2012 Google Inc.
 *
 * 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.ros.internal.node.service;

import org.apache.commons.logging.Log;
import org.ros.internal.node.BaseClientHandshake;
import org.ros.internal.transport.ConnectionHeader;
import org.ros.internal.transport.ConnectionHeaderFields;
import org.ros.log.RosLogFactory;

/**
 * Handshake logic from the client side of a service connection.
 *
 * @author damonkohler@google.com (Damon Kohler)
 */
public class ServiceClientHandshake extends BaseClientHandshake {

  private static final Log log = RosLogFactory.getLog(ServiceClientHandshake.class);

  public ServiceClientHandshake(ConnectionHeader outgoingConnectionHeader) {
    super(outgoingConnectionHeader);
  }

  @Override
  public boolean handshake(ConnectionHeader incommingConnectionHeader) {
    if (log.isDebugEnabled()) {
      log.debug("Outgoing service client connection header: " + outgoingConnectionHeader);
      log.debug("Incoming service server connection header: " + incommingConnectionHeader);
    }
    setErrorMessage(incommingConnectionHeader.getField(ConnectionHeaderFields.ERROR));
    if (getErrorMessage() != null) {
      return false;
    }
    if (!incommingConnectionHeader.getField(ConnectionHeaderFields.TYPE).equals(
        incommingConnectionHeader.getField(ConnectionHeaderFields.TYPE))) {
      setErrorMessage("Message types don't match.");
    }
    if (!incommingConnectionHeader.getField(ConnectionHeaderFields.MD5_CHECKSUM).equals(
        incommingConnectionHeader.getField(ConnectionHeaderFields.MD5_CHECKSUM))) {
      setErrorMessage("Checksums don't match.");
    }
    return getErrorMessage() == null;
  }
}