[4기 - 한희나] 1~2주차 과제 : 계산기 미션 제출합니다.

app/build.gradle

@@ -0,0 +1,48 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java application project to get you started.
+ * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
+ * User Manual available at https://docs.gradle.org/8.1.1/userguide/building_java_projects.html
+ * This project uses @Incubating APIs which are subject to change.
+ */
+
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id 'application'
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+    // This dependency is used by the application.
+    implementation 'com.google.guava:guava:31.1-jre'
+
+    // https://mvnrepository.com/artifact/org.assertj/assertj-core
+    testImplementation 'org.assertj:assertj-core:3.24.2'
+}
+
+testing {
+    suites {
+        // Configure the built-in test suite
+        test {
+            // Use JUnit Jupiter test framework
+            useJUnitJupiter('5.9.1')
+        }
+    }
+}
+
+// Apply a specific Java toolchain to ease working on different environments.
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(11)
+    }
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = 'com.programmers.App'
+}

app/src/main/java/com/programmers/App.java → app/src/main/java/com/programmers/CalculatorApplication.java

@@ -5,7 +5,7 @@
 
 import com.programmers.controller.CalculatorController;
 
-public class App {
+public class CalculatorApplication {
 
     public static void main(String[] args) {
 	    CalculatorController calculatorController = new CalculatorController();

app/src/main/java/com/programmers/calculator/Calculator.java

@@ -1,63 +1,20 @@
 package com.programmers.calculator;
 
-import java.util.*;
+import java.util.List;
 
 public class Calculator {
 
-	public List<String> changeInfixToPostfix(List<String> infix) {
-		List<String> postfix = new ArrayList<>();
-		Stack<String> stack = new Stack<>();
-
-		for (String s : infix) {
-			if (s.matches("\\d+")) { // 숫자일 경우
-				postfix.add(s);
-			} else { // 숫자 아닐 경우
-				int priority = getPriority(s);
-				// 스택이 비었거나
-				while (!stack.isEmpty()) {
-					String topOperator = stack.peek();
-					int topPriority = getPriority(topOperator);
-
-					// top의 우선 순위가 높거나 같을 경우
-					if (topPriority >= priority) postfix.add(stack.pop());
-					// top의 우선 순위가 낮을 경우
-					else break;
-				}
-				stack.push(s); // 연산자 넣음
-			}
-		}
-
-		// 스택에 남아있는 연산자 모두 집어 넣음
-		while (!stack.isEmpty()) postfix.add(stack.pop());
-
-		return postfix;
-	}
+	private final PostfixConversion postfixConversion;
+	private final PostfixCalculator postfixCalculator;
 
-	public Integer calcPostfix(List<String> postfix) {
-		Stack<Integer> stack = new Stack<>();
-
-		for (String s : postfix) {
-			// 숫자일 경우 스택에 넣음
-			if (s.matches("\\d+")) stack.push(Integer.parseInt(s));
-			else { // 연산자 일 경우
-				Integer op1 = stack.pop();
-				Integer op2 = stack.pop();
-
-				Operator calc = Operator.of(s);
-				Integer result = calc.getFunc().apply(op2, op1);
-
-				stack.push(result);
-			}
-		}
-
-		return stack.pop();
+	public Calculator() {
+		postfixConversion = new PostfixConversion();
+		postfixCalculator = new PostfixCalculator();
 	}
 
-	public Integer getPriority(String operator) {
-		// * 와 / 는 우선순위 높음
-		if (operator.equals("*") || operator.equals("/")) return 1;
-		// 그 외 낮음
-		return -1;
+	public Integer calculate(Formula formula) {
+		List<String> postfix = postfixConversion.changeInfixToPostfix(formula.getInfixListFormula());
+		return postfixCalculator.calculatePostfix(postfix);
 	}
 
 }

app/src/main/java/com/programmers/calculator/Formula.java

@@ -0,0 +1,44 @@
+package com.programmers.calculator;
+
+import com.programmers.exception.InvalidFormulaException;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+public class Formula {
+
+	private static final Pattern FORMULA_REGEX = Pattern.compile("([0-9] [+|\\-|*|/] )+[0-9]");
+	private static final String EQUAL = " = ";
+
+	private final Calculator calculator;
+
+	private String formula;
+	private Integer result;
+
+	public Formula(String formula) {
+		isValid(formula);
+		this.formula = formula;
+		this.calculator = new Calculator();
+	}
+
+	public List<String> getInfixListFormula() {
+		return Arrays.stream(formula.split(" "))
+			         .collect(Collectors.toList());
+	}
+
+	public void isValid(String formula) {
+		if (!FORMULA_REGEX.matcher(formula).matches()) throw new InvalidFormulaException("유효하지 않은 수식 입력입니다.");
+	}
+
+	public Integer calcualteFormula() {
+		result = calculator.calculate(this);
+		return result;
+	}
+
+	public String toString() {
+		return formula + EQUAL + result;
+	}
+
+}

app/src/main/java/com/programmers/calculator/PostfixCalculator.java

@@ -0,0 +1,38 @@
+package com.programmers.calculator;
+
+import com.programmers.util.Operator;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.List;
+import java.util.regex.Pattern;
+
+public class PostfixCalculator {
+
+	private static final Pattern NUMBER = Pattern.compile("\\d+");
+
+	public Integer calculatePostfix(List<String> postfix) {
+		Deque<Integer> deque = new ArrayDeque<>();
+
+		postfix.stream()
+				.forEach(s -> { calculatePostfixWithDeque(s, deque); });
+
+		return deque.pollLast();
+	}
+
+	private void calculatePostfixWithDeque(String s, Deque<Integer> deque) {
+		if (NUMBER.matcher(s).matches()) {
+			deque.addLast(Integer.parseInt(s));
+			return;
+		}
+		// 연산자 일 경우
+		Integer op1 = deque.pollLast();
+		Integer op2 = deque.pollLast();
+
+		Operator calc = Operator.of(s);
+		Integer result = calc.calculateOperation(op2, op1);
+
+		deque.addLast(result);
+	}
+
+}

app/src/main/java/com/programmers/calculator/PostfixConversion.java

@@ -0,0 +1,49 @@
+package com.programmers.calculator;
+
+import com.programmers.util.Operator;
+
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.ArrayDeque;
+import java.util.regex.Pattern;
+
+public class PostfixConversion {
+
+	private static final Pattern NUMBER = Pattern.compile("\\d+");
+
+	public List<String> changeInfixToPostfix(List<String> infix) {
+		List<String> postfix = new ArrayList<>();
+		Deque<String> deque = new ArrayDeque<>();
+
+		infix.stream()
+			 .forEach(s -> { makePostfixWithDeque(s, postfix, deque); });
+
+		// 스택에 남아있는 연산자 모두 집어 넣음
+		while (!deque.isEmpty()) postfix.add(deque.pollLast());
+
+		return postfix;
+	}
+
+	private void makePostfixWithDeque(String s, List<String> postfix, Deque<String> deque) {
+		if (NUMBER.matcher(s).matches()) { // 숫자일 경우
+			postfix.add(s);
+			return;
+		}
+		// 숫자 아닐 경우
+		Operator operator = Operator.of(s);
+		int priority = operator.getPriority();
+		// 덱이 비었거나
+		while (!deque.isEmpty()) {
+			Operator topOperator = Operator.of(deque.peekLast());
+			int topPriority = topOperator.getPriority();
+
+			// top의 우선 순위가 높거나 같을 경우
+			if (topPriority >= priority) postfix.add(deque.pollLast());
+				// top의 우선 순위가 낮을 경우
+			else break;
+		}
+		deque.addLast(s); // 연산자 넣음
+	}
+
+}