visitor pattern

src/main/java/visitor/CPU.java

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+package visitor;
+
+public class CPU implements ComputerPart{
+    @Override
+    public void accept(Visitor v) {
+        v.visitCPU(this);
+    }
+
+    @Override
+    public double getPrice() {
+        return 1880;
+    }
+}

src/main/java/visitor/CompanyVisitor.java

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+package visitor;
+
+public class CompanyVisitor implements Visitor{
+    double totalPrice = 0;
+    @Override
+    public void visitCPU(CPU cpu) {
+        totalPrice += cpu.getPrice() * 0.7;
+    }
+
+    @Override
+    public void visitMemory(Memory memory) {
+        totalPrice += memory.getPrice() * 0.7;
+
+    }
+
+    @Override
+    public void visitMainBoard(MainBoard mainBoard) {
+        totalPrice += mainBoard.getPrice() * 0.7;
+    }
+}

src/main/java/visitor/Computer.java

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+package visitor;
+
+public class Computer {
+    private ComputerPart cpu = new CPU();
+    private ComputerPart memory = new Memory();
+    private ComputerPart mainBoard = new MainBoard();
+
+    public void accept(Visitor v){
+        this.cpu.accept(v);
+        this.memory.accept(v);
+        this.mainBoard.accept(v);
+    }
+}

src/main/java/visitor/ComputerPart.java

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+package visitor;
+
+public interface ComputerPart {
+    void accept(Visitor v);
+    double getPrice();
+}

src/main/java/visitor/Main.java

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+package visitor;
+
+public class Main {
+    public static void main(String[] args) {
+        Computer computer = new Computer();
+        StudentVisitor visitor = new StudentVisitor();
+        computer.accept(visitor);
+        System.out.println(visitor.totalPrice);
+
+        CompanyVisitor visitor2 = new CompanyVisitor();
+        computer.accept(visitor2);
+        System.out.println(visitor2.totalPrice);
+    }
+}

src/main/java/visitor/MainBoard.java

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+package visitor;
+
+public class MainBoard implements ComputerPart{
+    @Override
+    public void accept(Visitor v) {
+        v.visitMainBoard(this);
+    }
+
+    @Override
+    public double getPrice() {
+        return 1200.5;
+    }
+}

src/main/java/visitor/Memory.java

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+package visitor;
+
+public class Memory implements ComputerPart{
+    @Override
+    public void accept(Visitor v) {
+        v.visitMemory(this);
+    }
+
+    @Override
+    public double getPrice() {
+        return 800;
+    }
+}

src/main/java/visitor/StudentVisitor.java

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+package visitor;
+
+public class StudentVisitor implements Visitor{
+    double totalPrice = 0;
+    @Override
+    public void visitCPU(CPU cpu) {
+        totalPrice += cpu.getPrice() * 0.9;
+    }
+
+    @Override
+    public void visitMemory(Memory memory) {
+        totalPrice += memory.getPrice() * 0.8;
+    }
+
+    @Override
+    public void visitMainBoard(MainBoard mainBoard) {
+        totalPrice += mainBoard.getPrice() * 0.95;
+    }
+}

src/main/java/visitor/Visitor.java

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+package visitor;
+
+public interface Visitor {
+    void visitCPU(CPU cpu);
+    void visitMemory(Memory memory);
+    void visitMainBoard(MainBoard mainBoard);
+}