Add Mediator (ES5 + ES6 + CoffeeScript + TypeScript)

Author: Badacadabra

doc/GoF/Behavioral/Mediator/Mediator.dia

@@ -0,0 +1,18 @@
+# Synopsis
+
+Tom and Dick are neighbors. Dick makes a lot of noise on Sunday mornings, which drives Tom crazy. Communication has become difficult between them because of this.
+
+# Problem
+
+If Tom and Dick cannot talk to each other directly, Dick will continue to make noise and Tom will get angry every Sunday.
+
+# Solution
+
+When communication is difficult between two objects or in a system (here the neighborhood), the solution is delegation to a third-party object. This object will make communication easier between all other objects.
+
+This is exactly the solution proposed by the Mediator pattern. To implement this pattern, we need:
+
+  * An abstract representation of a neighbor (abstract class should be preferred because it centralizes the reference to the mediator)
+  * An abstract representation of a neighborhood mediator (abstract class or interface)
+  * Concrete neighbors (Tom and Dick)
+  * A concrete mediator (Harry)

doc/GoF/Behavioral/Mediator/Mediator.png

@@ -0,0 +1,80 @@
+# ==============================
+# ABSTRACT COLLEAGUE 
+# ==============================
+
+class Neighbor
+    constructor: (mediator) ->
+        throw new Error "You cannot instantiate an abstract class!" if @constructor is Neighbor
+        @_mediator = mediator
+
+    send: (message) ->
+        throw new Error "You cannot instantiate an abstract class!"
+
+    receive: (message, sender) ->
+        throw new Error "You cannot instantiate an abstract class!"
+
+# ==============================
+# ABSTRACT MEDIATOR
+# ==============================
+
+class Mediator
+    constructor: ->
+        throw new Error "You cannot instantiate an abstract class!" if @constructor is Mediator
+
+    send: (message, neighbor) ->
+        throw new Error "You cannot instantiate an abstract class!"
+
+# ==============================
+# CONCRETE COLLEAGUES (NEIGHBORS)
+# ==============================
+
+class Tom extends Neighbor
+    constructor: (mediator) ->
+        super mediator
+
+    send: (message) ->
+        @_mediator.send(message, @)
+
+    receive: (message, sender) ->
+        "[Tom] Message from #{sender}: '#{message}'\n"
+
+class Dick extends Neighbor
+    constructor: (mediator) ->
+        super mediator
+
+    send: (message) ->
+        return @_mediator.send(message, @)
+
+    receive: (message, sender) ->
+        "[Dick] Message from #{sender}: '#{message}'\n"
+
+# ==============================
+# CONCRETE MEDIATOR 
+# ==============================
+
+class Harry extends Mediator
+    constructor: ->
+        @_tom = new Tom(@)
+        @_dick = new Dick(@)
+
+    send: (message, neighbor) ->
+        if neighbor instanceof Tom
+            @_dick.receive message, "Tom"
+        else if neighbor instanceof Dick
+            @_tom.receive message, "Dick"
+        else
+            throw new Error "Unknown neighbor"
+
+# ==============================
+# CLIENT CODE
+# ==============================
+
+harry = new Harry
+tom = new Tom harry
+dick = new Dick harry
+conversation = ""
+
+conversation += tom.send "Could you lower the volume of your music, please?"
+conversation += dick.send "Are you serious? The volume is actually very low..."
+
+console.log conversation

doc/GoF/Behavioral/Mediator/README.md

@@ -0,0 +1,87 @@
+// ==============================
+// ABSTRACT COLLEAGUE 
+// ==============================
+
+abstract class Neighbor {
+    protected mediator: Mediator;
+
+    constructor(mediator: Mediator) {
+        this.mediator = mediator;
+    }
+
+    public abstract send(message: string): string;
+    public abstract receive(message: string, sender: string): string;
+}
+
+// ==============================
+// ABSTRACT MEDIATOR
+// ==============================
+
+interface Mediator {
+    send(message: string, neighbor: Neighbor): string;
+}
+
+// ==============================
+// CONCRETE COLLEAGUES (NEIGHBORS)
+// ==============================
+
+class Tom extends Neighbor {
+    constructor(mediator: Mediator) {
+        super(mediator);
+    }
+
+    send(message: string): string {
+        return this.mediator.send(message, this);
+    }
+
+    receive(message: string, sender: string): string {
+        return `[Tom] Message from ${sender}: '${message}'\n`;
+    }
+}
+
+class Dick extends Neighbor {
+    constructor(mediator: Mediator) {
+        super(mediator);
+    }
+
+    send(message: string): string {
+        return this.mediator.send(message, this);
+    }
+
+    receive(message: string, sender: string): string {
+        return `[Dick] Message from ${sender}: '${message}'\n`;
+    }
+}
+
+// ==============================
+// CONCRETE MEDIATOR 
+// ==============================
+
+class Harry implements Mediator {
+    private tom: Tom = new Tom(this);
+    private dick: Dick = new Dick(this);
+
+    send(message: string, neighbor: Neighbor): string {
+        if (neighbor instanceof Tom) {
+            return this.dick.receive(message, "Tom");
+        } else if (neighbor instanceof Dick) {
+            return this.tom.receive(message, "Dick");
+        } else {
+            throw new Error("Unknown neighbor");
+        }
+    }
+}
+
+// ==============================
+// CLIENT CODE
+// ==============================
+
+let harry: Mediator = new Harry(),
+    tom: Neighbor = new Tom(harry),
+    dick: Neighbor = new Dick(harry),
+    conversation: string = "";
+
+conversation += tom.send("Could you lower the volume of your music, please?");
+conversation += dick.send("Are you serious? The volume is actually very low...");
+
+console.log(conversation);

src/CoffeeScript/GoF/Behavioral/Mediator/Mediator.coffee

@@ -0,0 +1,121 @@
+'use strict';
+
+// ==============================
+// ABSTRACT COLLEAGUE 
+// ==============================
+
+var Neighbor = (function() {
+    function Neighbor(mediator) {
+        if (this.constructor === Neighbor) {
+            throw new Error("You cannot instantiate an abstract class!");
+        }
+        this._mediator = mediator;
+    }
+
+    Neighbor.prototype.send = function (message) {
+        throw new Error("You cannot instantiate an abstract class!");
+    };
+
+    Neighbor.prototype.receive = function (message, sender) {
+        throw new Error("You cannot instantiate an abstract class!");
+    };
+
+    return Neighbor;
+})();
+
+// ==============================
+// ABSTRACT MEDIATOR
+// ==============================
+
+var Mediator = (function() {
+    function Mediator() {
+        if (this.constructor === Mediator) {
+            throw new Error("You cannot instantiate an abstract class!");
+        }
+    }
+
+    Mediator.prototype.send = function (message, neighbor) {
+        throw new Error("You cannot instantiate an abstract class!");
+    };
+
+    return Mediator;
+})();
+
+// ==============================
+// CONCRETE COLLEAGUES (NEIGHBORS)
+// ==============================
+
+var Tom = (function () {
+    function Tom(mediator) {
+        Neighbor.call(this, mediator);
+    }
+    Tom.prototype = Object.create(Neighbor.prototype);
+    Tom.prototype.constructor = Tom;
+
+    Tom.prototype.send = function (message) {
+        return this._mediator.send(message, this);
+    };
+
+    Tom.prototype.receive = function (message, sender) {
+        return "[Tom] Message from " + sender + ": '" + message + "'\n";
+    };
+
+    return Tom;
+})();
+
+var Dick = (function () {
+    function Dick(mediator) {
+        Neighbor.call(this, mediator);
+    }
+    Dick.prototype = Object.create(Neighbor.prototype);
+    Dick.prototype.constructor = Dick;
+
+    Dick.prototype.send = function (message) {
+        return this._mediator.send(message, this);
+    };
+
+    Dick.prototype.receive = function (message, sender) {
+        return "[Dick] Message from " + sender + ": '" + message + "'\n";
+    };
+
+    return Dick;
+})();
+
+// ==============================
+// CONCRETE MEDIATOR 
+// ==============================
+
+var Harry = (function () {
+    var tom = new Tom(this),
+        dick = new Dick(this);
+
+    function Harry() {}
+    Harry.prototype = Object.create(Mediator.prototype);
+    Harry.prototype.constructor = Harry;
+
+    Harry.prototype.send = function (message, neighbor) {
+        if (neighbor instanceof Tom) {
+            return dick.receive(message, "Tom");
+        } else if (neighbor instanceof Dick) {
+            return tom.receive(message, "Dick");
+        } else {
+            throw new Error("Unknown neighbor");
+        }
+    };
+
+    return Harry;
+})();
+
+// ==============================
+// CLIENT CODE
+// ==============================
+
+var harry = new Harry(),
+    tom = new Tom(harry),
+    dick = new Dick(harry),
+    conversation = "";
+
+conversation += tom.send("Could you lower the volume of your music, please?");
+conversation += dick.send("Are you serious? The volume is actually very low...");
+
+console.log(conversation);