Visitor Pattern Add: exercise

dmitrybor · dmitrybor · commit a6b608caae0c · 2021-04-13T08:45:38.000+06:00
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/BookElement.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/BookElement.java
@@ -0,0 +1,35 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public class BookElement implements Element {
+    private int price;
+    private int weight;
+
+    public BookElement(int price, int weight) {
+        this.price = price;
+        this.weight = weight;
+    }
+
+    @Override
+    public float accept(Visitor visitor) {
+        return visitor.visit(this);
+    }
+
+    @Override
+    public int getPrice() {
+        return price;
+    }
+
+    public void setPrice(int price) {
+        this.price = price;
+    }
+
+    @Override
+    public int getWeight() {
+        return weight;
+    }
+
+
+    public void setWeight(int weight) {
+        this.weight = weight;
+    }
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/CdElement.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/CdElement.java
@@ -0,0 +1,34 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public class CdElement implements Element{
+    private int price;
+    private int weight;
+
+    public CdElement(int price, int weight) {
+        this.price = price;
+        this.weight = weight;
+    }
+
+    @Override
+    public float accept(Visitor visitor) {
+        return visitor.visit(this);
+    }
+
+    @Override
+    public int getPrice() {
+        return price;
+    }
+
+    public void setPrice(int price) {
+        this.price = price;
+    }
+
+    @Override
+    public int getWeight() {
+        return weight;
+    }
+
+    public void setWeight(int weight) {
+        this.weight = weight;
+    }
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/Client.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/Client.java
@@ -0,0 +1,19 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+import java.util.List;
+
+public class Client {
+    public static void main(String[] args) {
+        List<Element> items = List.of(
+                new BookElement(35, 5),
+                new CdElement(3, 2),
+                new DvdElement(4, 2)
+        );
+        UsPostageVisitor usPostageVisitor = new UsPostageVisitor();
+        SouthAmericaPostageVisitor southAmericaPostageVisitor = new SouthAmericaPostageVisitor();
+        items.forEach(i -> i.accept(usPostageVisitor));
+        items.forEach(i -> i.accept(southAmericaPostageVisitor));
+        System.out.println("The total postage for shipping my items to the us is: " + usPostageVisitor.getTotal());
+        System.out.println("The total postage for shipping my items to the us is: " + southAmericaPostageVisitor.getTotal());
+    }
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/DvdElement.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/DvdElement.java
@@ -0,0 +1,34 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public class DvdElement implements Element {
+    private int price;
+    private int weight;
+
+    public DvdElement(int price, int weight) {
+        this.price = price;
+        this.weight = weight;
+    }
+
+    @Override
+    public float accept(Visitor visitor) {
+        return visitor.visit(this);
+    }
+
+    @Override
+    public int getPrice() {
+        return price;
+    }
+
+    public void setPrice(int price) {
+        this.price = price;
+    }
+
+    @Override
+    public int getWeight() {
+        return weight;
+    }
+
+    public void setWeight(int weight) {
+        this.weight = weight;
+    }
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/Element.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/Element.java
@@ -0,0 +1,7 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public interface Element {
+    float accept(Visitor visitor);
+    int getWeight();
+    int getPrice();
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/SouthAmericaPostageVisitor.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/SouthAmericaPostageVisitor.java
@@ -0,0 +1,33 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public class SouthAmericaPostageVisitor implements Visitor{
+    private float total = 0;
+
+    @Override
+    public float visit(BookElement element) {
+        return visit(element, 4);
+    }
+
+    @Override
+    public float visit(CdElement element) {
+        return visit(element, 5);
+    }
+
+    @Override
+    public float visit(DvdElement element) {
+        return visit(element, 6);
+    }
+
+    public float getTotal() {
+        return total;
+    }
+
+    private float visit(Element element, float costPerUnitWeight) {
+        if (element.getPrice() > 30) {
+            return 0;
+        }
+        float cost = element.getWeight() * costPerUnitWeight;
+        total += cost;
+        return cost;
+    }
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/UsPostageVisitor.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/UsPostageVisitor.java
@@ -0,0 +1,33 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public class UsPostageVisitor implements Visitor {
+    private float total = 0;
+
+    @Override
+    public float visit(BookElement element) {
+        return visit(element, 2);
+    }
+
+    @Override
+    public float visit(CdElement element) {
+        return visit(element, 2.5F);
+    }
+
+    @Override
+    public float visit(DvdElement element) {
+        return visit(element, 3);
+    }
+
+    public float getTotal() {
+        return total;
+    }
+
+    private float visit(Element element, float costPerUnitWeight) {
+        if (element.getPrice() > 20) {
+            return 0;
+        }
+        float cost = element.getWeight() * costPerUnitWeight;
+        total += cost;
+        return cost;
+    }
+}
diff --git a/src/main/java/com/lineate/bench/pattern/visitor/exercise/Visitor.java b/src/main/java/com/lineate/bench/pattern/visitor/exercise/Visitor.java
@@ -0,0 +1,9 @@
+package com.lineate.bench.pattern.visitor.exercise;
+
+public interface Visitor {
+    float visit(BookElement element);
+
+    float visit(CdElement element);
+
+    float visit(DvdElement element);
+}
