diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..f75cd2815
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,145 @@
+# Created by https://www.toptal.com/developers/gitignore/api/intellij+all,gradle,java
+# Edit at https://www.toptal.com/developers/gitignore?templates=intellij+all,gradle,java
+
+### Intellij+all ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# AWS User-specific
+.idea/**/aws.xml
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn. Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# SonarLint plugin
+.idea/sonarlint/
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Intellij+all Patch ###
+# Ignore everything but code style settings and run configurations
+# that are supposed to be shared within teams.
+
+.idea/*
+
+!.idea/codeStyles
+!.idea/runConfigurations
+
+### Java ###
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+replay_pid*
+
+### Gradle ###
+.gradle
+**/build/
+!src/**/build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Avoid ignore Gradle wrappper properties
+!gradle-wrapper.properties
+
+# Cache of project
+.gradletasknamecache
+
+# Eclipse Gradle plugin generated files
+# Eclipse Core
+.project
+# JDT-specific (Eclipse Java Development Tools)
+.classpath
+
+### Gradle Patch ###
+# Java heap dump
+*.hprof
+
+# End of https://www.toptal.com/developers/gitignore/api/intellij+all,gradle,java
\ No newline at end of file
diff --git a/.idea/codeStyles/codeStyleConfig.xml b/.idea/codeStyles/codeStyleConfig.xml
new file mode 100644
index 000000000..9a295ca74
--- /dev/null
+++ b/.idea/codeStyles/codeStyleConfig.xml
@@ -0,0 +1,5 @@
+
+
+
+
+
\ No newline at end of file
diff --git a/README.md b/README.md
index c1c982e55..ff60fab60 100644
--- a/README.md
+++ b/README.md
@@ -1,21 +1,6 @@
# java_calculator
자바 계산기 구현 미션 Repository입니다.
-### 이곳은 공개 Repo입니다.
-1. 여러분의 포트폴리오로 사용하셔도 됩니다.
-2. 때문에 이 repo를 fork한 뒤
-3. 여러분의 개인 Repo에 작업하며
-4. 이 Repo에 PR을 보내어 멘토의 코드 리뷰와 피드백을 받으세요.
-
-### Branch 명명 규칙 + 팀의 PR규칙 정하기
-1. 여러분 repo는 알아서 해주시고 😀(본인 레포니 main으로 하셔두 되져)
-2. prgrms-be-devcourse/spring-board 레포로 PR시 branch는 gituser_id을 적어주세요 :)
- - base repo : `여기repo` base : `username` ← head repo : `여러분repo` compare : `main`또는 `github_id`
-3. 실제 진행할 PR규칙은 멘토+팀원들과 정하여 진행해주세요 :)
- - ← head repo : `여러분repo` compare : `main`로 할지
- - 또는 ← head repo : `여러분repo` compare : `github_id`로 할지
-- 참고 : [Github 위치 및 피드백 기준 가이드](https://www.notion.so/backend-devcourse/Github-e1a0908a6bbf4aeaa5a62981499bb215)
-
### 과제를 통해 기대하는 역량
- 깃허브를 통한 코드리뷰를 경험해보자
diff --git a/build.gradle b/build.gradle
new file mode 100644
index 000000000..dca5fe47a
--- /dev/null
+++ b/build.gradle
@@ -0,0 +1,25 @@
+plugins {
+ id 'java'
+}
+
+group 'org.example'
+version '1.0-SNAPSHOT'
+
+repositories {
+ mavenCentral()
+}
+
+dependencies {
+
+ implementation 'org.apache.commons:commons-lang3:3.12.0'
+
+ implementation 'org.projectlombok:lombok'
+ implementation 'org.projectlombok:lombok:1.18.22'
+
+ testImplementation(platform('org.junit:junit-bom:5.9.3'))
+ testImplementation('org.junit.jupiter:junit-jupiter')
+}
+
+test {
+ useJUnitPlatform()
+}
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 000000000..249e5832f
Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 000000000..da1db5f04
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.0-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
new file mode 100644
index 000000000..a69d9cb6c
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,240 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+# Gradle start up script for POSIX generated by Gradle.
+#
+# Important for running:
+#
+# (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+# noncompliant, but you have some other compliant shell such as ksh or
+# bash, then to run this script, type that shell name before the whole
+# command line, like:
+#
+# ksh Gradle
+#
+# Busybox and similar reduced shells will NOT work, because this script
+# requires all of these POSIX shell features:
+# * functions;
+# * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+# «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+# * compound commands having a testable exit status, especially «case»;
+# * various built-in commands including «command», «set», and «ulimit».
+#
+# Important for patching:
+#
+# (2) This script targets any POSIX shell, so it avoids extensions provided
+# by Bash, Ksh, etc; in particular arrays are avoided.
+#
+# The "traditional" practice of packing multiple parameters into a
+# space-separated string is a well documented source of bugs and security
+# problems, so this is (mostly) avoided, by progressively accumulating
+# options in "$@", and eventually passing that to Java.
+#
+# Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+# and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+# see the in-line comments for details.
+#
+# There are tweaks for specific operating systems such as AIX, CygWin,
+# Darwin, MinGW, and NonStop.
+#
+# (3) This script is generated from the Groovy template
+# https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+# within the Gradle project.
+#
+# You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+ APP_HOME=${app_path%"${app_path##*/}"} # leaves a trailing /; empty if no leading path
+ [ -h "$app_path" ]
+do
+ ls=$( ls -ld "$app_path" )
+ link=${ls#*' -> '}
+ case $link in #(
+ /*) app_path=$link ;; #(
+ *) app_path=$APP_HOME$link ;;
+ esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+ echo "$*"
+} >&2
+
+die () {
+ echo
+ echo "$*"
+ echo
+ exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in #(
+ CYGWIN* ) cygwin=true ;; #(
+ Darwin* ) darwin=true ;; #(
+ MSYS* | MINGW* ) msys=true ;; #(
+ NONSTOP* ) nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+ if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+ # IBM's JDK on AIX uses strange locations for the executables
+ JAVACMD=$JAVA_HOME/jre/sh/java
+ else
+ JAVACMD=$JAVA_HOME/bin/java
+ fi
+ if [ ! -x "$JAVACMD" ] ; then
+ die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+ fi
+else
+ JAVACMD=java
+ which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+ case $MAX_FD in #(
+ max*)
+ MAX_FD=$( ulimit -H -n ) ||
+ warn "Could not query maximum file descriptor limit"
+ esac
+ case $MAX_FD in #(
+ '' | soft) :;; #(
+ *)
+ ulimit -n "$MAX_FD" ||
+ warn "Could not set maximum file descriptor limit to $MAX_FD"
+ esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+# * args from the command line
+# * the main class name
+# * -classpath
+# * -D...appname settings
+# * --module-path (only if needed)
+# * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+ APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+ CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+ JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+ # Now convert the arguments - kludge to limit ourselves to /bin/sh
+ for arg do
+ if
+ case $arg in #(
+ -*) false ;; # don't mess with options #(
+ /?*) t=${arg#/} t=/${t%%/*} # looks like a POSIX filepath
+ [ -e "$t" ] ;; #(
+ *) false ;;
+ esac
+ then
+ arg=$( cygpath --path --ignore --mixed "$arg" )
+ fi
+ # Roll the args list around exactly as many times as the number of
+ # args, so each arg winds up back in the position where it started, but
+ # possibly modified.
+ #
+ # NB: a `for` loop captures its iteration list before it begins, so
+ # changing the positional parameters here affects neither the number of
+ # iterations, nor the values presented in `arg`.
+ shift # remove old arg
+ set -- "$@" "$arg" # push replacement arg
+ done
+fi
+
+# Collect all arguments for the java command;
+# * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+# shell script including quotes and variable substitutions, so put them in
+# double quotes to make sure that they get re-expanded; and
+# * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+ "-Dorg.gradle.appname=$APP_BASE_NAME" \
+ -classpath "$CLASSPATH" \
+ org.gradle.wrapper.GradleWrapperMain \
+ "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+ die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+# readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+# set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+ printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+ xargs -n1 |
+ sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+ tr '\n' ' '
+ )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 000000000..f127cfd49
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,91 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/settings.gradle b/settings.gradle
new file mode 100644
index 000000000..bcf30bf6c
--- /dev/null
+++ b/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'java-calculator'
+
diff --git a/src/main/java/org/example/App.java b/src/main/java/org/example/App.java
new file mode 100644
index 000000000..45f0978ec
--- /dev/null
+++ b/src/main/java/org/example/App.java
@@ -0,0 +1,19 @@
+package org.example;
+
+import org.example.engine.Calculator;
+import org.example.engine.repository.CalculationRepository;
+import org.example.engine.repository.OrderedInmemoryCalculationRepository;
+
+public class App {
+ public static void main(String[] args) {
+
+ Console console = new Console();
+ CalculationRepository calculationRepository = new OrderedInmemoryCalculationRepository();
+ new Calculator(console, calculationRepository).run();
+
+ }
+
+}
+
+
+
diff --git a/src/main/java/org/example/Console.java b/src/main/java/org/example/Console.java
new file mode 100644
index 000000000..cb5fbbf0e
--- /dev/null
+++ b/src/main/java/org/example/Console.java
@@ -0,0 +1,34 @@
+package org.example;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+import org.apache.commons.lang3.StringUtils;
+import org.example.exception.CaculatorApplicationException;
+
+public class Console {
+ private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+ public int inputSelectMode() throws IOException, CaculatorApplicationException {
+ System.out.println("1. 조회");
+ System.out.println("2. 계산");
+ String inputSelectMode = br.readLine();
+ if (!(inputSelectMode.equals("1") || inputSelectMode.equals("2"))) {
+ throw new CaculatorApplicationException("Invalid input");
+ }
+ int mode = Integer.parseInt(inputSelectMode);
+ return mode;
+ }
+
+ public String inputExpression() throws IOException {
+ System.out.println("연산식을 입력해라");
+ String inputExpression = br.readLine();
+ return inputExpression;
+ }
+
+ public void outputSelectResult(int mode) {
+ System.out.printf("선택 : %d%n", mode);
+ }
+
+}
diff --git a/src/main/java/org/example/engine/Calculator.java b/src/main/java/org/example/engine/Calculator.java
new file mode 100644
index 000000000..835bf9779
--- /dev/null
+++ b/src/main/java/org/example/engine/Calculator.java
@@ -0,0 +1,146 @@
+package org.example.engine;
+
+import org.apache.commons.lang3.StringUtils;
+import org.example.Console;
+import org.example.engine.enums.ArithmeticOperator;
+import org.example.exception.CaculatorApplicationException;
+import org.example.engine.model.CalculationResult;
+import org.example.engine.repository.CalculationRepository;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Stack;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+public class Calculator implements Runnable {
+ private Console console;
+ private CalculationRepository calculationRepository;
+
+ public Calculator(Console console, CalculationRepository calculationRepository) {
+ this.console = console;
+ this.calculationRepository = calculationRepository;
+ }
+
+ @Override
+ public void run() {
+
+ while (true) {
+
+ try {
+ int mode = console.inputSelectMode();
+ console.outputSelectResult(mode);
+ switch (mode) {
+ case 1:
+ loadHistory();
+ break;
+ case 2:
+ compute();
+ break;
+ }
+ } catch (CaculatorApplicationException e1) {
+ System.out.println(e1.getMessage());
+ continue;
+ } catch (IOException e2) {
+ System.out.println(e2.getMessage());
+ continue;
+ }
+
+ }
+
+ }
+
+ public void compute() throws IOException, CaculatorApplicationException {
+ String inputExpression = console.inputExpression();
+ String preprocessedExpression = preprocess(inputExpression);
+ if (!validateExpression(preprocessedExpression)) {
+ throw new CaculatorApplicationException("Invalid expression");
+ }
+ List parseExpression = parseExpression(preprocessedExpression);
+ List postfixExpression = infixToPostfix(parseExpression);
+ Double result = calculate(postfixExpression);
+ System.out.println(result);
+ saveHistory(new CalculationResult(inputExpression, result));
+ }
+
+ public void loadHistory() {
+ List historyList = calculationRepository.findAll();
+ for (CalculationResult calculationResult : historyList) {
+ calculationResult.printInfo();
+ }
+ }
+
+ public String preprocess(String rowExpression) {
+ String preprocessedExpression = rowExpression.trim();
+ preprocessedExpression = preprocessedExpression.replaceAll("\\s+", "");
+ preprocessedExpression = preprocessedExpression.replaceAll("([+\\-*/])", " $1 ");
+
+ return preprocessedExpression;
+ }
+
+ public boolean validateExpression(String expression) {
+ String regex = "^\\d+(\\s*[+\\-*/]\\s*\\d+)*$";
+ return Pattern.matches(regex, expression);
+ }
+
+ public List parseExpression(String expression) {
+ return Arrays.stream(expression.split(" ")).collect(Collectors.toList());
+ }
+
+ public List infixToPostfix(List infixExpression) {
+ List postfixExpression = new ArrayList<>();
+ Stack st = new Stack<>();
+ for (String ele : infixExpression) {
+ if (StringUtils.isNumeric(ele)) {
+ postfixExpression.add(ele);
+ continue;
+ }
+
+ if (st.isEmpty()) {
+ st.add(ele);
+ continue;
+ }
+
+ ArithmeticOperator prevOperator = ArithmeticOperator.getArithmeticOperator(st.peek());
+ ArithmeticOperator tempOperator = ArithmeticOperator.getArithmeticOperator(ele);
+ if (ArithmeticOperator.comparePriority(prevOperator, tempOperator) < 0) {
+ st.add(ele);
+ } else {
+ while (!st.isEmpty())
+ postfixExpression.add(st.pop());
+ st.add(ele);
+ }
+ }
+
+ while (!st.isEmpty())
+ postfixExpression.add(st.pop());
+
+ return postfixExpression;
+ }
+
+ public double calculate(List postfixExpression) throws CaculatorApplicationException {
+
+ Stack st = new Stack<>();
+
+ for (String ele : postfixExpression) {
+ if (StringUtils.isNumeric(ele)) {
+ st.add(ele);
+ continue;
+ }
+
+ Double right = Double.parseDouble(st.pop());
+ Double left = Double.parseDouble(st.pop());
+ String arithmeticOperator = ele;
+ st.add(String.valueOf(ArithmeticOperator.calculate(arithmeticOperator, left, right)));
+ }
+
+ return Double.parseDouble(st.pop());
+ }
+
+ public int saveHistory(CalculationResult calculationResult) {
+ return calculationRepository.save(calculationResult);
+ }
+
+}
diff --git a/src/main/java/org/example/engine/enums/ArithmeticOperator.java b/src/main/java/org/example/engine/enums/ArithmeticOperator.java
new file mode 100644
index 000000000..f118f8e4e
--- /dev/null
+++ b/src/main/java/org/example/engine/enums/ArithmeticOperator.java
@@ -0,0 +1,53 @@
+package org.example.engine.enums;
+
+import java.util.Arrays;
+import java.util.function.BiFunction;
+
+import org.example.exception.CaculatorApplicationException;
+
+public enum ArithmeticOperator {
+ ADDITION("+", 1, (left, right) -> left + right),
+ SUBTRACTION("-", 1, (left, right) -> left - right),
+ MULTIPLICATION("*", 2, (left, right) -> left * right),
+ DIVISION("/", 2, (Dividend, Divisor) -> {
+ if (Divisor != 0) {
+ return Dividend / Divisor;
+ } else {
+ throw new CaculatorApplicationException("Cannot divide by zero");
+ }
+
+ });
+
+ private String arithmeticOperator;
+ private final int priority;
+ private BiFunction expression;
+
+ ArithmeticOperator(String arithmeticOperator, int priority, BiFunction expression) {
+ this.arithmeticOperator = arithmeticOperator;
+ this.priority = priority;
+ this.expression = expression;
+ }
+
+ public String getArithmeticOperator() {
+ return arithmeticOperator;
+ }
+
+ public int getPriority() {
+ return priority;
+ }
+
+ public static ArithmeticOperator getArithmeticOperator(String arithmeticOperator) {
+ return Arrays.stream(values())
+ .filter(o -> o.arithmeticOperator.equals(arithmeticOperator))
+ .findFirst().orElseThrow(() -> new CaculatorApplicationException("Invalid operator."));
+ }
+
+ public static int comparePriority(ArithmeticOperator operator1, ArithmeticOperator operator2) {
+ return Integer.compare(operator1.getPriority(), operator2.getPriority());
+ }
+
+ public static double calculate(String arithmeticOperator, double num1, double num2) {
+ return getArithmeticOperator(arithmeticOperator).expression.apply(num1, num2);
+ }
+
+}
diff --git a/src/main/java/org/example/engine/model/CalculationResult.java b/src/main/java/org/example/engine/model/CalculationResult.java
new file mode 100644
index 000000000..0ddfa4b0a
--- /dev/null
+++ b/src/main/java/org/example/engine/model/CalculationResult.java
@@ -0,0 +1,18 @@
+package org.example.engine.model;
+
+import lombok.ToString;
+
+@ToString
+public class CalculationResult {
+ private String expression;
+ private Double result;
+
+ public CalculationResult(String expression, Double result) {
+ this.expression = expression;
+ this.result = result;
+ }
+
+ public void printInfo() {
+ System.out.printf("%s = %f%n", this.expression, this.result);
+ }
+}
diff --git a/src/main/java/org/example/engine/repository/CalculationRepository.java b/src/main/java/org/example/engine/repository/CalculationRepository.java
new file mode 100644
index 000000000..aa9426625
--- /dev/null
+++ b/src/main/java/org/example/engine/repository/CalculationRepository.java
@@ -0,0 +1,16 @@
+package org.example.engine.repository;
+
+import org.example.engine.model.CalculationResult;
+
+import java.util.List;
+
+public interface CalculationRepository {
+ public int save(CalculationResult calculationResult);
+
+ public List findAll();
+
+ public void clear();
+
+ public int size();
+
+}
diff --git a/src/main/java/org/example/engine/repository/OrderedInmemoryCalculationRepository.java b/src/main/java/org/example/engine/repository/OrderedInmemoryCalculationRepository.java
new file mode 100644
index 000000000..8e893329f
--- /dev/null
+++ b/src/main/java/org/example/engine/repository/OrderedInmemoryCalculationRepository.java
@@ -0,0 +1,38 @@
+package org.example.engine.repository;
+
+import org.example.engine.model.CalculationResult;
+
+import java.util.*;
+
+public class OrderedInmemoryCalculationRepository implements CalculationRepository {
+ private static Long id;
+ private static Map memoryDB;
+
+ public OrderedInmemoryCalculationRepository() {
+ id = 0L;
+ this.memoryDB = new LinkedHashMap<>();
+ }
+
+ @Override
+ public int save(CalculationResult calculationResult) {
+ memoryDB.put(id, calculationResult);
+ id++;
+ return 0;
+ }
+
+ @Override
+ public List findAll() {
+ return new ArrayList<>(memoryDB.values());
+ }
+
+ @Override
+ public void clear() {
+ memoryDB.clear();
+ id = 0L;
+ }
+
+ @Override
+ public int size() {
+ return memoryDB.size();
+ }
+}
diff --git a/src/main/java/org/example/exception/CaculatorApplicationException.java b/src/main/java/org/example/exception/CaculatorApplicationException.java
new file mode 100644
index 000000000..e2dce6641
--- /dev/null
+++ b/src/main/java/org/example/exception/CaculatorApplicationException.java
@@ -0,0 +1,13 @@
+package org.example.exception;
+
+import lombok.Getter;
+
+@Getter
+public class CaculatorApplicationException extends RuntimeException {
+ private String message;
+
+ public CaculatorApplicationException(String message) {
+ this.message = message;
+ }
+
+}
diff --git a/src/test/java/org/example/engine/CalculatorTest.java b/src/test/java/org/example/engine/CalculatorTest.java
new file mode 100644
index 000000000..51df49430
--- /dev/null
+++ b/src/test/java/org/example/engine/CalculatorTest.java
@@ -0,0 +1,136 @@
+package org.example.engine;
+
+import org.example.Console;
+import org.example.engine.repository.CalculationRepository;
+import org.example.engine.repository.OrderedInmemoryCalculationRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class CalculatorTest {
+ Console console;
+ CalculationRepository calculationRepository;
+ Calculator calculator;
+
+ @BeforeEach
+ void setUp() {
+ this.console = new Console();
+ this.calculationRepository = new OrderedInmemoryCalculationRepository();
+ this.calculator = new Calculator(this.console, this.calculationRepository);
+ }
+
+ @DisplayName("사칙연산 공백 전처리 테스트")
+ @Test
+ void preprocessExpressionTest() {
+ String rowExpression = " 1 + 2 3 / 3 * 8 - 2 ";
+ String preprocessedExpression = "1 + 23 / 3 * 8 - 2";
+ assertEquals(preprocessedExpression, calculator.preprocess(rowExpression));
+ }
+
+ @DisplayName("사칙연산 입력 검증 통과 테스트")
+ @ParameterizedTest
+ @MethodSource("passValidateExpressionTestData")
+ void passValidateExpressionTest(String expression) {
+ boolean expected = true;
+ boolean actual = calculator.validateExpression(expression);
+ assertEquals(expected, actual);
+ }
+
+ @DisplayName("사칙연산 입력 검증 실페 테스트")
+ @ParameterizedTest
+ @MethodSource("failValidateExpressionTestData")
+ void failValidateExpressionTest(String expression) {
+ boolean expected = false;
+ boolean actual = calculator.validateExpression(expression);
+ assertEquals(expected, actual);
+ }
+
+ @DisplayName("문자열 형태의 연산 입력값을 공백을 기준으로 분리한 리스트 변환")
+ @Test
+ void parseExpressionTest() {
+ String expression = "1 + 2 / 3 * 4 - 5";
+ List expected = Arrays.asList("1", "+", "2", "/", "3", "*", "4", "-", "5");
+ List actual = calculator.parseExpression(expression);
+ assertEquals(expected, actual);
+
+ }
+
+ @DisplayName("연산자 우선순위를 반영하여 중위식 표현의 연산입력값을 후위식으로 표현")
+ @ParameterizedTest
+ @MethodSource("infixToPostfixTestData")
+ void infixToPostfixTest(List input, List output) {
+ List expected = output;
+ List actual = calculator.infixToPostfix(input);
+ assertEquals(expected, actual);
+ }
+
+ @DisplayName("연산자 우선순위를 반영하여 중위식 표현의 연산입력값을 후위식으로 표현")
+ @ParameterizedTest
+ @MethodSource("caluateTestData")
+ void calulateTest(List postfixExpression, Double output) {
+ System.out.println(calculator.calculate(postfixExpression));
+ Double expected = output;
+ Double actual = calculator.calculate(postfixExpression);
+ assertEquals(expected, actual);
+ }
+
+ @DisplayName("0으로 나눌시 예외 반환")
+ @Test
+ void calulateTest2() {
+
+ List postfixExpression = Arrays.asList("1", "0", "/");
+
+ assertThrows(ArithmeticException.class, () -> {
+ double result = calculator.calculate(postfixExpression);
+ });
+
+ }
+
+ private static List passValidateExpressionTestData() {
+ return Arrays.asList(
+ "1 + 2 / 3 * 4 - 5",
+ "1 + 2 / 3 * 4 - 5",
+ "1+2/3*4",
+ "2222222222+33333333/4*777777-2"
+ );
+ }
+
+ private static List failValidateExpressionTestData() {
+ return Arrays.asList(
+ "1 + 2 / 3 * 4 -",
+ "1 + + 2 / 3 * 4 - 5",
+ "1+2/ 3 4",
+ " "
+ );
+ }
+
+ private static Stream infixToPostfixTestData() {
+
+ return Stream.of(
+ Arguments.of(Arrays.asList("1", "+", "2", "*", "3"), Arrays.asList("1", "2", "3", "*", "+")),
+ Arguments.of(Arrays.asList("1", "-", "2", "/", "3"), Arrays.asList("1", "2", "3", "/", "-")),
+ Arguments.of(Arrays.asList("1", "+", "2", "-", "3"), Arrays.asList("1", "2", "+", "3", "-")),
+ Arguments.of(Arrays.asList("1", "/", "2", "*", "3"), Arrays.asList("1", "2", "/", "3", "*"))
+ );
+ }
+
+ private static Stream caluateTestData() {
+
+ return Stream.of(
+ Arguments.of(Arrays.asList("1", "2", "3", "*", "+"), 6.0),
+ Arguments.of(Arrays.asList("1", "2", "3", "/", "-"), 1.6666666666666665),
+ Arguments.of(Arrays.asList("1", "2", "+", "3", "-"), 6.0),
+ Arguments.of(Arrays.asList("1", "2", "/", "3", "*"), 3.5)
+ );
+ }
+
+}
\ No newline at end of file
diff --git a/src/test/java/org/example/engine/repository/OrderedInmemoryCalculationRepositoryTest.java b/src/test/java/org/example/engine/repository/OrderedInmemoryCalculationRepositoryTest.java
new file mode 100644
index 000000000..067a042c8
--- /dev/null
+++ b/src/test/java/org/example/engine/repository/OrderedInmemoryCalculationRepositoryTest.java
@@ -0,0 +1,45 @@
+package org.example.engine.repository;
+
+import org.example.engine.model.CalculationResult;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class OrderedInmemoryCalculationRepositoryTest {
+ CalculationRepository calculationRepository;
+
+ @BeforeEach
+ void setup() {
+ this.calculationRepository = new OrderedInmemoryCalculationRepository();
+ }
+
+ @Test
+ void save() {
+ String expression = "1 + 2 + 3";
+ Double result = 6.0;
+ CalculationResult calculationResult = new CalculationResult(expression, result);
+ assertEquals(0L, calculationRepository.save(calculationResult));
+ }
+
+ @Test
+ void findAll() {
+ String expression = "1 + 2 + 3";
+ Double result = 6.0;
+ for (int i = 0; i < 10; i++) {
+ calculationRepository.save(new CalculationResult(expression, result));
+ }
+ assertEquals(10, calculationRepository.findAll().size());
+ }
+
+ @Test
+ void clear() {
+ String expression = "1 + 2 + 3";
+ Double result = 6.0;
+ for (int i = 0; i < 10; i++) {
+ calculationRepository.save(new CalculationResult(expression, result));
+ }
+ calculationRepository.clear();
+ assertEquals(0, calculationRepository.size());
+ }
+}
\ No newline at end of file