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Refactor the command pattern to use lambda functions

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We can leverage the lambda expressins of Java 8 onwards
to implement command design pattern instead of traditional
non functional way
This commit is contained in:
Rakesh Venkatesh
2020-09-30 17:56:12 +02:00
parent 1f4a412e70
commit 4ff196ce35
11 changed files with 206 additions and 434 deletions
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201
command/etc/command.ucls
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@@ -1,116 +1,89 @@
<?xml version="1.0" encoding="UTF-8"?>
<class-diagram version="1.1.8" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true"
realizations="true" associations="true" dependencies="false" nesting-relationships="true">
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file="/command/src/main/java/com/iluwatar/command/ShrinkSpell.java" binary="false" corner="BOTTOM_RIGHT">
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<operations public="true" package="true" protected="true" private="true" static="true"/>
</display>
</class>
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file="/command/src/main/java/com/iluwatar/command/Goblin.java" binary="false" corner="BOTTOM_RIGHT">
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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file="/command/src/main/java/com/iluwatar/command/Wizard.java" binary="false" corner="BOTTOM_RIGHT">
<position height="-1" width="-1" x="129" y="362"/>
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
sort-features="false" accessors="true" visibility="true">
<attributes public="true" package="true" protected="true" private="true" static="true"/>
<operations public="true" package="true" protected="true" private="true" static="true"/>
</display>
</class>
<class id="4" language="java" name="com.iluwatar.command.Command" project="command"
file="/command/src/main/java/com/iluwatar/command/Command.java" binary="false" corner="BOTTOM_RIGHT">
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<operations public="true" package="true" protected="true" private="true" static="true"/>
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<display labels="true" multiplicity="true"/>
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<display labels="true" multiplicity="true"/>
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<classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
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<position height="-1" width="-1" x="129" y="1223"/>
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<display labels="true" multiplicity="true"/>
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<generalization id="18">
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<display labels="true" multiplicity="true"/>
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<classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
sort-features="false" accessors="true" visibility="true">
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</class-diagram>
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41
command/etc/command.urm.puml
View File

@@ -4,33 +4,11 @@ package com.iluwatar.command {
+ App()
+ main(args : String[]) {static}
}
interface Command {
+ Command()
+ execute(Target) {abstract}
+ redo() {abstract}
+ toString() : String {abstract}
+ undo() {abstract}
}
class Goblin {
+ Goblin()
+ toString() : String
}
class InvisibilitySpell {
- target : Target
+ InvisibilitySpell()
+ execute(target : Target)
+ redo()
+ toString() : String
+ undo()
}
class ShrinkSpell {
- oldSize : Size
- target : Target
+ ShrinkSpell()
+ execute(target : Target)
+ redo()
+ toString() : String
+ undo()
+ changeSize()
+ changeVisibility()
}
enum Size {
+ NORMAL {static}
@@ -62,22 +40,19 @@ package com.iluwatar.command {
}
class Wizard {
- LOGGER : Logger {static}
- redoStack : Deque<Command>
- undoStack : Deque<Command>
- redoStack : Deque<Runnable>
- undoStack : Deque<Runnable>
+ Wizard()
+ castSpell(command : Command, target : Target)
+ castSpell(Runnable : runnable)
+ redoLastSpell()
+ toString() : String
+ undoLastSpell()
}
}
Target --> "-size" Size
Wizard --> "-undoStack" Command
ShrinkSpell --> "-oldSize" Size
InvisibilitySpell --> "-target" Target
ShrinkSpell --> "-target" Target
Wizard --> "-changeSize" Goblin
Wizard --> "-changeVisibility" Goblin
Target --> "-visibility" Visibility
Goblin --|> Target
InvisibilitySpell ..|> Command
ShrinkSpell ..|> Command
App --> "castSpell" Wizard
@enduml