Merge pull request #74 from cxyterence/update-dg

Update DeveloperGuide.md with implementation of ShowCommand

docs/DeveloperGuide.md

@@ -377,6 +377,48 @@ _{more aspects and alternatives to be added}_
 
 _{Explain here how the data archiving feature will be implemented}_
 
+### Display Details of Contacts in Secondary Panel
+
+#### Implementation
+
+This feature is facilitated by `ShowCommand`, which extends `Command` with an index, stored internally as `index`.
+It overwrites the following operations:
+* `ShowCommand#execute()` — Executes the command, displaying the details of the contact at the specified index.
+* `ShowCommand#equals(Object o)` — Checks if two objects are equal.
+
+Given below is an example usage scenario and how the displaying mechanism behaves at each step.
+
+Step 1. The user launches the application. The `AddressBook` will initially display all Persons with their `Positions`.
+
+![ShowDiagram1](images/ShowDiagram1.png)
+
+Step 2. The user executes `show 1` command to display the details of the first contact shown. The `show` keyowrd causes
+`AddressBookParser#parseCommand()` to call `ShowCommandParser#parse()`. This returns a `ShowCommand` containing the
+`index 1`.
+
+![ShowDiagram2](images/ShowDiagram2.png)
+
+Step 3. `Model` retrieves the `Person` object located at `index 1`. This returns a `CommandResult` containing the `Person`
+object.
+
+![ShowDiagram3](images/ShowDiagram3.png)
+
+Step 4. `MainWindow` from `UI` component will process the `CommandResult` and display the details found inside the
+included `Person` object.
+
+The following show diagram shows how the show operation works:
+
+![ShowSequenceDiagram](images/ShowSequenceDiagram.png)
+
+#### Design Considerations
+* **Alternative 1 (current choice):** Passing `Person` object to `MainWindow`
+    * Pros: Reduced coupling throughout the program
+    * Cons: Changing of many method signatures, unintuitive to implement at first.
+
+* **Alternative 2:** Passing `index` to `MainWindow` to retrieve details from `Model`
+    * Pros: More intuitive to implement in the sense that only `MainWindow` would be primarily modified.
+    * Cons: Increased coupling, violation of Law of Demeter.
+
 ### Multiple Teacher’s Address Books (TABs)
 **Feature Summary**
 - Users are able to create multiple TABs (currently limited to 5).

docs/diagrams/ShowDiagram1.puml

@@ -0,0 +1,19 @@
+@startuml
+'https://plantuml.com/object-diagram
+
+object "<u> Walter:Person" as Walter {
+    position = "Professor"
+    phone = "91234567"
+}
+
+object "<u> Jesse:Person" as Jesse {
+    position = "Student"
+    phone = "98765432"
+}
+
+map "<u> :AddressBook" as AddressBook {
+    <u>:Person1 *-> Walter
+    <u>:Person2 *--> Jesse
+}
+
+@enduml

docs/diagrams/ShowDiagram2.puml

@@ -0,0 +1,17 @@
+@startuml
+'https://plantuml.com/class-diagram
+class ShowCommand
+class Index {}
+
+ShowCommand *-- Index
+
+class ShowCommand {
+-COMMAND_WORD
+-index
+equals()
+execute()
+}
+class Index {
+-zeroBasedIndex = 1
+}
+@enduml

docs/diagrams/ShowDiagram3.puml

@@ -0,0 +1,20 @@
+@startuml
+'https://plantuml.com/object-diagram
+
+object "<u> Walter:Person" as Walter {
+    position = "Professor"
+    phone = "91234567"
+}
+
+object "<u> Jesse:Person" as Jesse {
+    position = "Student"
+    phone = "98765432"
+}
+
+object "<u> :List<Person>" as lastShownList
+lastShownList --> Walter
+lastShownList --> Jesse
+
+object "<u> :CommandResult" as CommandResult
+CommandResult --> Walter
+@enduml

docs/diagrams/ShowSequenceDiagram.puml

@@ -0,0 +1,58 @@
+@startuml
+!include style.puml
+
+box Logic LOGIC_COLOR_T1
+participant ":LogicManager" as LogicManager LOGIC_COLOR
+participant ":AddressBookParser" as AddressBookParser LOGIC_COLOR
+participant "s:ShowCommand" as ShowCommand LOGIC_COLOR
+end box
+
+box Model MODEL_COLOR_T1
+participant ":Model" as Model MODEL_COLOR
+participant ":List<Person>" as ListPerson MODEL_COLOR
+participant "personToShow:Person" as personToShow MODEL_COLOR
+end box
+[-> LogicManager : execute(show)
+activate LogicManager
+
+LogicManager -> AddressBookParser : parseCommand(show)
+activate AddressBookParser
+
+create ShowCommand
+AddressBookParser -> ShowCommand
+activate ShowCommand
+
+ShowCommand --> AddressBookParser
+deactivate ShowCommand
+
+AddressBookParser --> LogicManager : s
+deactivate AddressBookParser
+
+LogicManager -> ShowCommand : execute()
+activate ShowCommand
+
+ShowCommand -> Model : getFilteredPersonList()
+activate Model
+
+Model -> ListPerson
+activate ListPerson
+
+ListPerson -> personToShow : get(index.getZeroBased())
+activate personToShow
+
+personToShow --> ListPerson
+deactivate personToShow
+
+ListPerson --> Model
+deactivate ListPerson
+
+Model --> ShowCommand : personToShow
+deactivate Model
+
+ShowCommand --> LogicManager
+deactivate ShowCommand
+
+[<-- LogicManager
+deactivate LogicManager
+
+@enduml