Add view command to DG

docs/DeveloperGuide.md

@@ -209,6 +209,21 @@ The following object diagram illustrates the above:
 The following sequence diagram shows the addpolicy operation:
 <puml src="diagrams/AddPolicySequenceDiagram.puml" width="900" />
 
+### View Client feature
+
+The view client feature allows users to view the details of a client using their `INDEX` on the GUI. This includes information not included in the client list cards, such as their last met and policy list.
+
+#### Implementation
+
+The view client mechanism is facilitated by `DisplayClient` in the model. When any command referring to a client using `INDEX` is executed, this DisplayClient is set to the client that was operated on (or cleared to `null` in the case of `delete` and `clear`). 
+This is done with the `setDisplayClient()` function in the `Model`, that is also implemented in `Logic`.
+
+
+The sequence diagram below shows the execution of `view 1` to view the details of client at index 1.
+<puml src="diagrams/ViewClientSequenceDiagram.puml" width="900" />
+
+`MainWindow` handles most of the UI logic in regard to displaying the viewed client on the GUI, including refreshing the `ClientDetailsPanel` and `ClientPolicyTable`. It also sets `DisplayClient` on startup when there is at least one client in the list.
+
 ### \[Proposed\] Undo/redo feature
 
 #### Proposed Implementation

docs/diagrams/ViewClientSequenceDiagram.puml

@@ -0,0 +1,67 @@
+@startuml
+!include style.puml
+skinparam ArrowFontStyle plain
+
+box Logic LOGIC_COLOR_T1
+participant ":LogicManager" as LogicManager LOGIC_COLOR
+participant ":AddressBookParser" as AddressBookParser LOGIC_COLOR
+participant ":ViewCommandParser" as ViewCommandParser LOGIC_COLOR
+participant "v:ViewCommand" as ViewCommand LOGIC_COLOR
+participant "r:CommandResult" as CommandResult LOGIC_COLOR
+end box
+
+box Model MODEL_COLOR_T1
+participant "m:Model" as Model MODEL_COLOR
+end box
+
+[-> LogicManager : execute("view 1")
+activate LogicManager
+
+LogicManager -> AddressBookParser : parseCommand("view 1")
+activate AddressBookParser
+
+create ViewCommandParser
+AddressBookParser -> ViewCommandParser
+activate ViewCommandParser
+
+ViewCommandParser --> AddressBookParser
+deactivate ViewCommandParser
+
+AddressBookParser -> ViewCommandParser : parse("1")
+activate ViewCommandParser
+
+create ViewCommand
+ViewCommandParser -> ViewCommand
+activate ViewCommand
+
+ViewCommand --> ViewCommandParser : v
+deactivate ViewCommand
+
+ViewCommandParser --> AddressBookParser : v
+deactivate ViewCommandParser
+
+AddressBookParser --> LogicManager : v
+deactivate AddressBookParser
+
+LogicManager -> ViewCommand : execute(m)
+activate ViewCommand
+
+ViewCommand -> Model : setDisplayClient(personToView)
+activate Model
+
+Model --> ViewCommand
+deactivate Model
+
+create CommandResult
+ViewCommand -> CommandResult
+activate CommandResult
+
+CommandResult --> ViewCommand
+deactivate CommandResult
+
+ViewCommand --> LogicManager : r
+deactivate ViewCommand
+
+[<--LogicManager
+deactivate LogicManager
+@enduml