#Non Blocking Server In this exercise we will implement a basic client-server application, such that server would be non-blocking. The communication between clients and server will be done via TCP.
##Client Side Client will have a command line user interface that includes the following commands:
-
Login <CLIENT_NAME> - logs this client into the system
-
Logout – logs this client out from the system
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SendMessageToClient <CLIENT_NAME_TO_SEND>| - send a dedicated message to a specific logged in client
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BroadcastNessageToAllClients - send a message to all logged in clients
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GetAllLoggedInClients – return all logged in clients
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GetDBData – get All DB data via the following format.
- Currently, DB data is returned via JSON format only, but there is a requirement from USA headquarters to extend the support to other formats. Please note that. When getting the data, client needs to parse it and print it to the console in a well formatted way.
- Please see table 1 for example.
- Client will communicate through server for all commands. Client A cannot access client directly.
- All commands are having a unique identifier that will be sent to server. You can assume that client name is also unique.
- Client will not be blocked due to performing operations against server. Some of the server operation mat take time – please consider that!
- Server will need to react to all clients’ commands.
- Per each command from client, server will return a message to the sender OR to another client OR to all clients. Please see table 1 for example.
- You can safely assume that the max number of clients is 20.
- You need to consider that some of the server operations may take time.
- Currently, DB data is returned via JSON format only, but there is a requirement from US headquarters to extend the support to other formats. Please note that.
- Currently, the data is located at the DB_data.json file located in your eclipse project.
##Commands and Corresponding Output Examples
| Operation | User Interface Command | Server Operation |
|---|---|---|
| Shimi is logging in | Login Shimi | Hello Shimi. You are logged in. |
| Moshe is logging in | Login Moshe | Hello Moshe. You are logged in. |
| Yossi is logging in | Login Yossi | Hello Yossi. You are logged in. |
| Shimi is logging out | Logout | Server is sending Shimi: “Goodbye Shimi. You are logged out.” Server is sending the rest of the logged in clients: “Shimi has logged out”. |
| Baruch is sending a message to Moshe | SendMessageToClient Moshe: Hello Moshe! How are you? | Server is sending to Moshe only a message: “Baruch sent you a message: hello Moshe! How are you??” |
| Baruch is sending a broadcast message | BroadcastNessageToAllClients hello folks! Let’s go dancing tonight | Server is sending to all clients (besides Baruch) the message: “Hello folks! Let’s go dancing tonight” |
| Baruch is requesting DB data from server | GetDBData JSON | DB data in JSON format is sent to Baruch |
| Moshe is asking for all logged in clients | GetAllLoggedInClients | Server is returning: “The logged in clients are: Moshe, Yossi, Baruch” |
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