Merge pull request #157 from JerryWang0000/branch-Find-DG

Add implementation details for `Find` feature in DeveloperGuide

docs/DeveloperGuide.md

@@ -196,6 +196,41 @@ This is to prevent `FilterCommand` from taking on more responsibilities (Separat
 `FilterCommand` having `setPersonPredicate()` method:
 This is so that `FilterCommand` has the required argument of type `Predicate<Person>` to be used in the `updateFilteredPersonList()` method. Since the `Predicate<Person>` object is created by chaining the multiple predicates, no parsing is involved to create this `Predicate`.
 
+### Find feature
+
+#### How the feature is implemented
+
+The sequence diagram below explains how the find command `find Alex` goes through the `Logic` component.
+
+![Interactions Inside the Logic Component for the `find Alex` Command](images/FindSequenceDiagram.png)
+
+<div markdown="span" class="alert alert-info">:information_source: **Note:** The lifeline for `FindCommandParser` should end at the destroy marker (X) but due to a limitation of PlantUML, the lifeline continues till the end of diagram.
+</div>
+
+1. When user types in `find Alex`, it is passed to `StaffConnectParser`.
+2. `StaffconnectParser` then creates a `FindCommandParser` that will parse `Alex` to create a `FindCommand` which utilizes a predicate judge whether `Alex` is contained in the person's name. 
+3. In `FindCommand`, `Model` executes `updateFilteredPersonList()` method using the predicate mentioned above.
+4. The result of the command execution is encapsulated as a `CommandResult` object which is returned back from `Logic`, to show in the `UI` component the number of persons listed with `Alex` in the name.
+
+The below sequence diagram goes into more detail on how the command is parsed in `EditCommandParser`.
+
+![Interactions Inside FindCommandParser for the `parse("f/Computing")` Command](images/FindSequenceDiagram-Parser.png)
+
+1. Within `FindCommandParser`, the command string is first trimmed and checked whether it is empty, then splitted into an string array by space characters.
+2. `FindCommandParser` then constructs a predicate to test whether the names of `Person` contain any one of the strings in the array mentioned above. This predicate is passed as an argument for the constructor of `FindCommand`.
+
+The below activity diagram illustrates the process when a user executes a find command.
+
+<img src="images/FindActivityDiagram.png" width="250" />
+
+#### Why find is implemented this way
+
+The main operation for the find feature is the `updateFilteredPersonList(Predicate<Person> predicate)` method in the `Model` component.
+Below are some explanations for the special considerations in the implementation.
+
+`FindCommmandParser` parsing the `Predicate` objects:
+This is to prevent `FindCommand` from taking on more responsibilities (Separation of Concerns).
+
 ### \[Proposed\] Undo/redo feature
 
 #### Proposed Implementation

docs/diagrams/FindActivityDiagram.puml

@@ -0,0 +1,21 @@
+@startuml
+skin rose
+skinparam ActivityFontSize 15
+skinparam ArrowFontSize 12
+start
+:User executes find command;
+
+'Since the beta syntax does not support placing the condition outside the
+'diamond we place it as the true branch instead.
+
+if () then ([command is non-empty])
+    if () then ([Person fulfils criteria])
+        :Show in list;
+    else ([else])
+        :Not shown in list;
+    endif
+else ([else])
+    :Show error message to User;
+endif
+stop
+@enduml

docs/diagrams/FindSequenceDiagram-Parser.puml

@@ -0,0 +1,30 @@
+@startuml
+!include style.puml
+skinparam ArrowFontStyle plain
+skinparam ParticipantPadding 0
+
+Participant ":FindCommandParser" as FindCommandParser LOGIC_COLOR
+Participant ":FindCommand" as FindCommand LOGIC_COLOR
+Participant "p:NameContainsKeywordsPredicate" as p LOGIC_COLOR
+
+
+[-> FindCommandParser : parse("Alex")
+create FindCommandParser
+activate FindCommandParser
+
+create p
+FindCommandParser -> p: new("Alex")
+activate p
+p --> FindCommandParser
+deactivate p
+
+create FindCommand
+FindCommandParser -> FindCommand: new(p)
+activate FindCommand
+
+FindCommand --> FindCommandParser
+deactivate FindCommand
+
+[<-- FindCommandParser
+deactivate FindCommandParser
+@enduml

docs/diagrams/FindSequenceDiagram.puml

@@ -0,0 +1,73 @@
+@startuml
+!include style.puml
+skinparam ArrowFontStyle plain
+
+box Logic LOGIC_COLOR_T1
+participant ":LogicManager" as LogicManager LOGIC_COLOR
+participant ":StaffConnectParser" as StaffConnectParser LOGIC_COLOR
+participant ":FindCommandParser" as FindCommandParser LOGIC_COLOR
+participant "f:FindCommand" as FindCommand 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("find Alex")
+activate LogicManager
+
+LogicManager -> StaffConnectParser : parseCommand("find Alex")
+activate StaffConnectParser
+
+create FindCommandParser
+StaffConnectParser -> FindCommandParser
+activate FindCommandParser
+
+FindCommandParser --> StaffConnectParser
+deactivate FindCommandParser
+
+StaffConnectParser -> FindCommandParser : parse("Alex")
+activate FindCommandParser
+
+create FindCommand
+FindCommandParser -> FindCommand: new(NameContainsKeywordsPredicate)
+activate FindCommand
+
+FindCommand --> FindCommand
+deactivate FindCommand
+
+FindCommand --> FindCommandParser :
+deactivate FindCommand
+
+FindCommandParser --> StaffConnectParser : f
+deactivate FindCommandParser
+'Hidden arrow to position the destroy marker below the end of the activation bar.
+FindCommandParser -[hidden]-> StaffConnectParser
+destroy FindCommandParser
+
+StaffConnectParser --> LogicManager : f
+deactivate StaffConnectParser
+
+LogicManager -> FindCommand : execute(m)
+activate FindCommand
+
+FindCommand -> Model : updateFilteredPersonList(NameContainsKeywordsPredicate)
+activate Model
+
+Model --> FindCommand
+deactivate Model
+
+create CommandResult
+FindCommand -> CommandResult
+activate CommandResult
+
+CommandResult --> FindCommand
+deactivate CommandResult
+
+FindCommand --> LogicManager : r
+deactivate FindCommand
+
+[<-- LogicManager
+deactivate LogicManager
+@enduml