state gummball

README.md

@@ -11,6 +11,7 @@
 3. [Команда](command/)
 4. [Шаблонный метод](templatemethod/)
 5. [Итератор](iterator/)
+6. [Состояние](state/)
 
 ### Структурные
 

state/README.md

@@ -0,0 +1,5 @@
+# Состояние
+
+Поведенческий паттерн проектирования, который позволяет объектам менять поведение в зависимости от своего состояния. Извне создаётся впечатление, что изменился класс объекта.
+
+

state/gumballmachine/app.d

@@ -0,0 +1,40 @@
+module app;
+
+import gumballmachine;
+import std.stdio : writeln;
+
+void main()
+{
+    GumballMachine gumballMachine = new GumballMachine(5);
+
+    writeln(gumballMachine);
+
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+
+    writeln(gumballMachine);
+
+    gumballMachine.insertQuarter();
+    gumballMachine.ejectQuarter();
+    gumballMachine.turnCrank();
+
+    writeln(gumballMachine);
+
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+    gumballMachine.ejectQuarter();
+
+    writeln(gumballMachine);
+
+    gumballMachine.insertQuarter();
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+
+    writeln(gumballMachine);
+}

state/gumballmachine/gumballmachine.d

@@ -0,0 +1,155 @@
+module gumballmachine;
+
+import std.stdio : writeln;
+import std.conv : to;
+
+class GumballMachine
+{
+    static const int SOLD_OUT = 0;      // нет шариков
+    static const int NO_QUARTER = 1;    // нет монетки
+    static const int HAS_QUARTER = 2;   // есть монетка
+    static const int SOLD = 3;          // шарик продан
+
+    int state = SOLD_OUT;
+    int count = 0;
+
+    this(int count)
+    {
+        this.count = count;
+        if (count > 0)
+        {
+            state = NO_QUARTER;
+        }
+    }
+
+    void insertQuarter()
+    {
+        if (state == HAS_QUARTER)
+        {
+            writeln("You can't insert another quarter");
+        }
+        else if (state == NO_QUARTER)
+        {
+            state = HAS_QUARTER;
+            writeln("You inserted a quarter");
+        }
+        else if (state == SOLD_OUT)
+        {
+            writeln("You can't insert a quarter, the machine is sold out");
+        }
+        else if (state == SOLD)
+        {
+            writeln("Please wait, we're already giving you a gumball");
+        }
+    }
+
+    void ejectQuarter()
+    {
+        if (state == HAS_QUARTER)
+        {
+            writeln("Quarter returned");
+            state = NO_QUARTER;
+        }
+        else if (state == NO_QUARTER)
+        {
+            writeln("You haven't inserted a quarter");
+        }
+        else if (state == SOLD)
+        {
+            writeln("Sorry, you already turned the crank");
+        }
+        else if (state == SOLD_OUT)
+        {
+            writeln("You can't eject, you haven't inserted a quarter yet");
+        }
+    }
+ 
+    void turnCrank()
+    {
+        if (state == SOLD)
+        {
+            writeln("Turning twice doesn't get you another gumball!");
+        }
+        else if (state == NO_QUARTER)
+        {
+            writeln("You turned but there's no quarter");
+        }
+        else if (state == SOLD_OUT)
+        {
+            writeln("You turned, but there are no gumballs");
+        }
+        else if (state == HAS_QUARTER)
+        {
+            writeln("You turned...");
+            state = SOLD;
+            dispense();
+        }
+    }
+ 
+    private void dispense()
+    {
+        if (state == SOLD)
+        {
+            writeln("A gumball comes rolling out the slot");
+            --count;
+            if (count == 0)
+            {
+                writeln("Oops, out of gumballs!");
+                state = SOLD_OUT;
+            }
+            else
+            {
+                state = NO_QUARTER;
+            }
+        }
+        else if (state == NO_QUARTER)
+        {
+            writeln("You need to pay first");
+        }
+        else if (state == SOLD_OUT)
+        {
+            writeln("No gumball dispensed");
+        }
+        else if (state == HAS_QUARTER)
+        {
+            writeln("No gumball dispensed");
+        }
+    }
+ 
+    void refill(int numGumBalls)
+    {
+        this.count = numGumBalls;
+        state = NO_QUARTER;
+    }
+
+    override string toString() const
+    {
+        string s;
+        s ~= "\nMighty Gumball, Inc.";
+        s ~= "\nJava-enabled Standing Gumball Model #2004\n";
+        s ~= "Inventory: " ~ count.to!string ~ " gumball";
+        if (count != 1)
+        {
+            s ~= "s";
+        }
+        s ~= "\nMachine is ";
+        if (state == SOLD_OUT)
+        {
+            s ~= "sold out";
+        }
+        else if (state == NO_QUARTER)
+        {
+            s ~= "waiting for quarter";
+        }
+        else if (state == HAS_QUARTER)
+        {
+            s ~= "waiting for turn of crank";
+        }
+        else if (state == SOLD)
+        {
+            s ~= "delivering a gumball";
+        }
+        s ~= "\n";
+        return s;
+    }
+}

state/gumballmachinestate/app.d

@@ -0,0 +1,27 @@
+module app;
+
+import gumballmachine;
+import std.stdio : writeln;
+
+void main()
+{
+    GumballMachine gumballMachine = new GumballMachine(2);
+
+    writeln(gumballMachine);
+
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+
+    writeln(gumballMachine);
+
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+
+    gumballMachine.refill(5);
+    gumballMachine.insertQuarter();
+    gumballMachine.turnCrank();
+
+    writeln(gumballMachine);
+}

state/gumballmachinestate/gumballmachine.d

@@ -0,0 +1,116 @@
+module gumballmachine;
+
+import std.stdio : writeln;
+import std.conv : to;
+import soldoutstate, noquarterstate, hasquarterstate, soldstate, state;
+
+class GumballMachine
+{ 
+    State soldOutState;
+    State noQuarterState;
+    State hasQuarterState;
+    State soldState;
+ 
+    State state;
+    int count = 0;
+ 
+    this(int numberGumballs)
+    {
+        soldOutState = new SoldOutState(this);
+        noQuarterState = new NoQuarterState(this);
+        hasQuarterState = new HasQuarterState(this);
+        soldState = new SoldState(this);
+
+        this.count = numberGumballs;
+        if (numberGumballs > 0)
+        {
+            state = noQuarterState;
+        }
+        else
+        {
+            state = soldOutState;
+        }
+    }
+ 
+    void insertQuarter()
+    {
+        state.insertQuarter();
+    }
+ 
+    void ejectQuarter()
+    {
+        state.ejectQuarter();
+    }
+ 
+    void turnCrank()
+    {
+        state.turnCrank();
+        state.dispense();
+    }
+ 
+    void releaseBall()
+    {
+        writeln("A gumball comes rolling out the slot...");
+        if (count > 0)
+        {
+            count = count - 1;
+        }
+    }
+ 
+    int getCount()
+    {
+        return count;
+    }
+ 
+    void refill(int count)
+    {
+        this.count += count;
+        writeln("The gumball machine was just refilled; its new count is: ", this.count);
+        state.refill();
+    }
+
+    void setState(State state)
+    {
+        this.state = state;
+    }
+
+    State getState()
+    {
+        return state;
+    }
+
+    State getSoldOutState()
+    {
+        return soldOutState;
+    }
+
+    State getNoQuarterState()
+    {
+        return noQuarterState;
+    }
+
+    State getHasQuarterState()
+    {
+        return hasQuarterState;
+    }
+
+    State getSoldState()
+    {
+        return soldState;
+    }
+ 
+    override string toString() const
+    {
+        string s;
+        s ~= "\nMighty Gumball, Inc.";
+        s ~= "\nJava-enabled Standing Gumball Model #2004";
+        s ~= "\nInventory: " ~ count.to!string ~ " gumball";
+        if (count != 1)
+        {
+            s ~= "s";
+        }
+        s ~= "\n";
+        s ~= "Machine is " ~ state.to!string ~ "\n";
+        return s;
+    }
+}

state/gumballmachinestate/hasquarterstate.d

@@ -0,0 +1,43 @@
+module hasquarterstate;
+
+import std.stdio : writeln;
+import state, gumballmachine;
+
+class HasQuarterState : State
+{
+    GumballMachine gumballMachine;
+ 
+    this(GumballMachine gumballMachine)
+    {
+        this.gumballMachine = gumballMachine;
+    }
+  
+    void insertQuarter()
+    {
+        writeln("You can't insert another quarter");
+    }
+ 
+    void ejectQuarter()
+    {
+        writeln("Quarter returned");
+        gumballMachine.setState(gumballMachine.getNoQuarterState());
+    }
+ 
+    void turnCrank()
+    {
+        writeln("You turned...");
+        gumballMachine.setState(gumballMachine.getSoldState());
+    }
+
+    void dispense()
+    {
+        writeln("No gumball dispensed");
+    }
+    
+    void refill() {}
+ 
+    override string toString() const
+    {
+        return "waiting for turn of crank";
+    }
+}

state/gumballmachinestate/noquarterstate.d

@@ -0,0 +1,42 @@
+module noquarterstate;
+
+import std.stdio : writeln;
+import state, gumballmachine;
+
+class NoQuarterState : State
+{
+    GumballMachine gumballMachine;
+ 
+    this(GumballMachine gumballMachine)
+    {
+        this.gumballMachine = gumballMachine;
+    }
+ 
+    void insertQuarter()
+    {
+        writeln("You inserted a quarter");
+        gumballMachine.setState(gumballMachine.getHasQuarterState());
+    }
+ 
+    void ejectQuarter()
+    {
+        writeln("You haven't inserted a quarter");
+    }
+ 
+    void turnCrank()
+    {
+        writeln("You turned, but there's no quarter");
+    }
+ 
+    void dispense()
+    {
+        writeln("You need to pay first");
+    } 
+    
+    void refill() { }
+ 
+    override string toString() const
+    {
+        return "waiting for quarter";
+    }
+}

state/gumballmachinestate/soldoutstate.d

@@ -0,0 +1,44 @@
+module soldoutstate;
+
+import std.stdio : writeln;
+import state, gumballmachine;
+
+class SoldOutState : State
+{
+    GumballMachine gumballMachine;
+ 
+    this(GumballMachine gumballMachine)
+    {
+        this.gumballMachine = gumballMachine;
+    }
+ 
+    void insertQuarter()
+    {
+        writeln("You can't insert a quarter, the machine is sold out");
+    }
+ 
+    void ejectQuarter()
+    {
+        writeln("You can't eject, you haven't inserted a quarter yet");
+    }
+ 
+    void turnCrank()
+    {
+        writeln("You turned, but there are no gumballs");
+    }
+ 
+    void dispense()
+    {
+        writeln("No gumball dispensed");
+    }
+    
+    void refill()
+    { 
+        gumballMachine.setState(gumballMachine.getNoQuarterState());
+    }
+ 
+    override string toString() const
+    {
+        return "sold out";
+    }
+}

state/gumballmachinestate/soldstate.d

@@ -0,0 +1,50 @@
+module soldstate;
+
+import std.stdio : writeln;
+import state, gumballmachine;
+
+class SoldState : State
+{ 
+    GumballMachine gumballMachine;
+ 
+    this(GumballMachine gumballMachine)
+    {
+        this.gumballMachine = gumballMachine;
+    }
+       
+    void insertQuarter()
+    {
+        writeln("Please wait, we're already giving you a gumball");
+    }
+ 
+    void ejectQuarter()
+    {
+        writeln("Sorry, you already turned the crank");
+    }
+ 
+    void turnCrank()
+    {
+        writeln("Turning twice doesn't get you another gumball!");
+    }
+ 
+    void dispense()
+    {
+        gumballMachine.releaseBall();
+        if (gumballMachine.getCount() > 0)
+        {
+            gumballMachine.setState(gumballMachine.getNoQuarterState());
+        }
+        else
+        {
+            writeln("Oops, out of gumballs!");
+            gumballMachine.setState(gumballMachine.getSoldOutState());
+        }
+    }
+    
+    void refill() {}
+ 
+    override string toString() const
+    {
+        return "dispensing a gumball";
+    }
+}

state/gumballmachinestate/state.d

@@ -0,0 +1,11 @@
+module state;
+
+interface State
+{
+    void insertQuarter();
+    void ejectQuarter();
+    void turnCrank();
+    void dispense();
+
+    void refill();
+}