test

Client SocketListener  // The Socket listener of the client
Server SocketListener  // The Socket server
Client Socket(address)  // Send data to the server 
ServerSocket.accept(address)  // Receive data 
Switch(Socket){  // Jump to sub-modules 
  case Location_Update:
    update user_data  // Update user data 
    update group_data  // Update grouping data
    update group_location  // Update a group location
    break
  case Location_Request:
    if(group_location valid)  /* Determine if there is a 
latest group location satisfying precision requirements. */          
      Socket.output(group_location)  
    else 
      Socket.output(GPS_on_demand)  
    break
  default: logout(“null”)
}