When the message arrives at the server side, it is to send a message to all clients, no concept of a group.
There should be a new group, and then join a group chat. After a group chat, a message will be sent a notification to all clients in the group chat.
Can also group chat, chat messages sent after exiting the group will not be received by the client.
Second, the class description
ConnectorHandlerChain: Handler chain connecting structure
ConnectorCloseChain: Close ligation chain structure
ConnectorStringPacketChain: receiving a configuration string, the string package encapsulation
DefaultNonConnectorStringPacketChain: Default String receiving node, do not do anything
DefaultPrintConnectorCloseChain: the close link chain structure
ParseCommandConnectorStringPacketChain: parsing command, create groups, join a group, remove a group
ForwardConnectorStringPacketChain: forwarding chain structure
Third, 类图
Fourth, each ClientHandler contain many processing chain structure
Fifth, join groups
Sixth, the group removed
Seven, within the group members to send messages, group members will receive the message, but the members of the group can not receive outside messages
