Package org.web3d.vrml.scripting.external.neteai

Class NetworkProtocolConstants

java.lang.Object
org.web3d.vrml.scripting.external.neteai.NetworkProtocolConstants
public abstract class NetworkProtocolConstants extends Object
NetworkProtocolConstants is a utility class for specifying constants for the communications framework and utility methods for reading and writing data. Upon opening a connection, the client will transmit the integer CONNECTION_MAGIC_NUMBER_CLIENT and expect to read CONNECTION_MAGIC_NUMBER_SERVER. The server expects to read CONNECTION_MAGIC_NUMBER_CLIENT and then transmits CONNECTION_MAGIC_NUMBER_SERVER. Deviation from this handshake routine causes the connection to be closed. The network protocol is broken into a sequence of packets. Requests from the client to the server follows the format of <PACKET_TYPE> <PACKET_ID> <PACKET_DATA> Responses to client requests follow the format <PACKET_TYPE> <PACKET_ID> <RESPONSE_TYPE> <PACKET_DATA> where PACKET_ID for a response matches the PACKET_ID of the original request, and RESPONSE_TYPE is a normal response (calling method should return normally), an unexpected error (calling method should indicate a run time exception), or a routine exception response (calling method should generate an expected exception). For spontaneous client to server messages such as the various event notifications, the format is instead <PACKET_TYPE> <PACKET_DATA> The format of PACKET_DATA is naturally specific to the packet type. When dealing with arrays, the array length is transmitted before the array elements. For null arrays an array length of -1 is specified. For Node objects only the ID number of each node is specified. The ID -1 is reserved to specify a null Node object. Strings are transmitted using the readUTF and writeUTF methods. All other field types (int, float, etc.) use the appropriate read and write methods on the data input/output stream.