copied spring project

.gitignore

@@ -13,3 +13,45 @@
 .externalNativeBuild
 .cxx
 local.properties
+
+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+data.mv.db
+data.trace.db
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+node_modules

backend/README.md

@@ -0,0 +1,2 @@
+# IP_1_Kalyshev_Yan_PIbd-22
+

backend/build.gradle

@@ -0,0 +1,33 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '3.2.0'
+	id 'io.spring.dependency-management' version '1.1.4'
+}
+
+group = 'com.kalyshev'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '17'
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
+	implementation 'org.springframework.boot:spring-boot-devtools'
+	implementation 'nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect'
+
+	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+	implementation 'com.h2database:h2'
+
+	implementation 'org.hibernate.validator:hibernate-validator'
+
+	//implementation 'org.springdoc:springdoc-openapi-ui'
+
+	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+}
+
+tasks.named('test') {
+	useJUnitPlatform()
+}

backend/gradlew

@@ -0,0 +1,249 @@
+#!/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/HEAD/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
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&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: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$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
+
+
+# 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"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+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 "$JAVACMD" "$@"

backend/gradlew.bat

@@ -0,0 +1,92 @@
+@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=.
+@rem This is normally unused
+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

backend/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'yan'

backend/src/main/java/com/kalyshev/yan/WebConfiguration.java

@@ -0,0 +1,20 @@
+package com.kalyshev.yan;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.CorsRegistry;
+import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@Configuration
+public class WebConfiguration implements WebMvcConfigurer {
+    public static final String REST_API = "/api";
+    @Override
+    public void addViewControllers(ViewControllerRegistry registry) {
+        WebMvcConfigurer.super.addViewControllers(registry);
+        registry.addViewController("rest-test");
+    }
+    @Override
+    public void addCorsMappings(CorsRegistry registry) {
+        registry.addMapping("/**").allowedMethods("*");
+    }
+}

backend/src/main/java/com/kalyshev/yan/YanApplication.java

@@ -0,0 +1,11 @@
+package com.kalyshev.yan;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class YanApplication {
+	public static void main(String[] args) {
+		SpringApplication.run(YanApplication.class, args);
+	}
+}

backend/src/main/java/com/kalyshev/yan/cabinet/controller/CabinetController.java

@@ -0,0 +1,64 @@
+package com.kalyshev.yan.cabinet.controller;
+
+import com.kalyshev.yan.WebConfiguration;
+import com.kalyshev.yan.cabinet.service.CabinetService;
+import com.kalyshev.yan.computer.controller.ComputerDto;
+import jakarta.validation.Valid;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping(WebConfiguration.REST_API + "/cabinet")
+public class CabinetController {
+    private final CabinetService cabinetService;
+    public CabinetController(CabinetService cabinetService) {
+        this.cabinetService = cabinetService;
+    }
+    @GetMapping("/{id}")
+    public CabinetDto getCabinet(@PathVariable Long id) {
+        return new CabinetDto(cabinetService.findCabinet(id));
+    }
+    @GetMapping("/")
+    public List<CabinetDto> getCabinets() {
+        return cabinetService.findAllCabinets().stream()
+                .map(CabinetDto::new)
+                .toList();
+    }
+    @GetMapping("/{id}/computers")
+    public List<ComputerDto> getCabinetComputers(@PathVariable Long id) {
+        return cabinetService.listComputersFromCabinet(id).stream()
+                .map(ComputerDto::new)
+                .toList();
+    }
+    @GetMapping("/filter")
+    public List<CabinetDto> getFilteredCabinets(@RequestParam(value = "id", required = false) Long id,
+                                         @RequestParam(value = "number", required = false) String number) {
+        return cabinetService.findFilteredCabinets(id, number).stream()
+                .map(CabinetDto::new)
+                .toList();
+    }
+    @PostMapping("/")
+    public CabinetDto createCabinet(@RequestBody @Valid CabinetDto cabinetDto) {
+        return new CabinetDto(cabinetService.addCabinet(cabinetDto.getNumber()));
+    }
+    @PostMapping("/{id}/computer")
+    public void createCabinetComputer(@PathVariable Long id,
+                                          @RequestParam("computerId") Long computerId) {
+        cabinetService.addComputerToCabinet(computerId, id);
+    }
+    @PutMapping("/{id}")
+    public CabinetDto updateCabinet(@PathVariable Long id,
+                                    @RequestBody @Valid CabinetDto cabinetDto) {
+        return new CabinetDto(cabinetService.updateCabinet(id, cabinetDto.getNumber()));
+    }
+    @DeleteMapping("/{id}")
+    public CabinetDto deleteCabinet(@PathVariable Long id) {
+        return new CabinetDto(cabinetService.deleteCabinet(id));
+    }
+    @DeleteMapping("/{cabinetId}/computer")
+    public void deleteCabinetComputer(@PathVariable Long cabinetId,
+                                             @RequestParam("computerId") Long computerId) {
+        cabinetService.deleteComputerFromCabinet(computerId, cabinetId);
+    }
+}

backend/src/main/java/com/kalyshev/yan/cabinet/controller/CabinetDto.java

@@ -0,0 +1,33 @@
+package com.kalyshev.yan.cabinet.controller;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.computer.model.Computer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class CabinetDto {
+    private Long id;
+    private String number;
+    private List<Long> computerIds;
+    public CabinetDto() {}
+    public CabinetDto(Cabinet cabinet) {
+        this.id = cabinet.getId();
+        this.number = cabinet.getNumber();
+        if (cabinet.getComputers() == null) {
+            this.computerIds = new ArrayList<>();
+        } else {
+            this.computerIds = new ArrayList<>();
+            List<Computer> computers = cabinet.getComputers();
+            for (Computer computer : computers) {
+                computerIds.add(computer.getId());
+            }
+        }
+    }
+    public Long getId() { return this.id; }
+    public void setId(Long id) { this.id = id; }
+    public String getNumber() { return this.number; }
+    public void setNumber(String number) { this.number = number; }
+    public List<Long> getComputerIds() { return this.computerIds; }
+    public void setComputerIds(List<Long> computerIds) { this.computerIds = computerIds; }
+}

backend/src/main/java/com/kalyshev/yan/cabinet/model/Cabinet.java

@@ -0,0 +1,71 @@
+package com.kalyshev.yan.cabinet.model;
+
+import com.kalyshev.yan.computer.model.Computer;
+import jakarta.persistence.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+@Entity
+@Table(name = "cabinet")
+public class Cabinet {
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String number;
+    @OneToMany(cascade = {CascadeType.MERGE})
+    private List<Computer> computers;
+
+    public Cabinet() {
+    }
+    public Cabinet(String number) {
+        this.number = number;
+    }
+    public Long getId() {
+        return id;
+    }
+    public String getNumber() {
+        return number;
+    }
+    public void setNumber(String number) {
+        this.number = number;
+    }
+    public List<Computer> getComputers() {
+        return computers;
+    }
+    public void addComputer(Computer computer){
+        if (computers == null){
+            this.computers = new ArrayList<>();
+        }
+        if (!computers.contains(computer)) {
+            this.computers.add(computer);
+            computer.setCabinet(this);
+        }
+    }
+    public void removeComputer(Computer computer){
+        if (computers.contains(computer))
+            this.computers.remove(computer);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (!(o instanceof Cabinet))
+            return false;
+        Cabinet cabinet = (Cabinet) o;
+        return Objects.equals(id, cabinet.id) && Objects.equals(this.number, cabinet.number);
+    }
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+    @Override
+    public String toString() {
+        return "Cabinet{" +
+                "id=" + id +
+                ", number='" + number + '\'' +
+                '}';
+    }
+}

backend/src/main/java/com/kalyshev/yan/cabinet/repository/CabinetNotFoundException.java

@@ -0,0 +1,7 @@
+package com.kalyshev.yan.cabinet.repository;
+
+public class CabinetNotFoundException extends RuntimeException {
+    public CabinetNotFoundException(Long id) {
+        super(String.format("Cabinet with id [%s] is not found", id));
+    }
+}

backend/src/main/java/com/kalyshev/yan/cabinet/repository/CabinetRepository.java

@@ -0,0 +1,15 @@
+package com.kalyshev.yan.cabinet.repository;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.monitor.model.Monitor;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+
+import java.util.List;
+
+public interface CabinetRepository extends JpaRepository<Cabinet, Long> {
+    @Query(value = "select s from Cabinet s where (s.id = :id or :id is Null) and (s.number = :number or :number is Null)")
+    public List<Cabinet> findFilteredCabinets(@Param("id") Long id,
+                                              @Param("number") String number);
+}

backend/src/main/java/com/kalyshev/yan/cabinet/service/CabinetService.java

@@ -0,0 +1,104 @@
+package com.kalyshev.yan.cabinet.service;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.cabinet.repository.CabinetNotFoundException;
+import com.kalyshev.yan.cabinet.repository.CabinetRepository;
+import com.kalyshev.yan.computer.model.Computer;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.util.validation.ValidatorUtil;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.util.StringUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+
+@Service
+public class CabinetService {
+    private final CabinetRepository cabinetRepository;
+    private final ComputerService computerService;
+    private final ValidatorUtil validatorUtil;
+    public CabinetService(CabinetRepository cabinetRepository,
+                          ComputerService computerService,
+                          ValidatorUtil validatorUtil) {
+        this.cabinetRepository = cabinetRepository;
+        this.computerService = computerService;
+        this.validatorUtil = validatorUtil;
+    }
+    @Transactional
+    public Cabinet addCabinet(String number) {
+        if (!StringUtils.hasText(number)) {
+            throw new IllegalArgumentException("Cabinet number is null or empty");
+        }
+        final Cabinet cabinet = new Cabinet(number);
+        validatorUtil.validate(cabinet);
+        return cabinetRepository.save(cabinet);
+    }
+    @Transactional(readOnly = true)
+    public Cabinet findCabinet(Long id) {
+        final Optional<Cabinet> cabinet = cabinetRepository.findById(id);
+        return cabinet.orElseThrow(() -> new CabinetNotFoundException(id));
+    }
+    @Transactional(readOnly = true)
+    public List<Cabinet> findFilteredCabinets(Long id, String number) {
+        return cabinetRepository.findFilteredCabinets(id, number);
+    }
+    @Transactional(readOnly = true)
+    public List<Cabinet> findAllCabinets() {
+        return cabinetRepository.findAll();
+    }
+    @Transactional
+    public Cabinet updateCabinet(Long id, String number) {
+        if (!StringUtils.hasText(number)) {
+            throw new IllegalArgumentException("Cabinet number is null or empty");
+        }
+        final Cabinet currentCabinet = findCabinet(id);
+        currentCabinet.setNumber(number);
+        validatorUtil.validate(currentCabinet);
+        return cabinetRepository.save(currentCabinet);
+    }
+    @Transactional
+    public Cabinet deleteCabinet(Long id) {
+        final Cabinet currentCabinet = findCabinet(id);
+        computerService.deleteRelationsWithCabinets(currentCabinet.getComputers());
+        cabinetRepository.delete(currentCabinet);
+        return currentCabinet;
+    }
+    @Transactional
+    public void deleteAllCabinets() {
+        cabinetRepository.deleteAll();
+    }
+    @Transactional
+    public List<Computer> listComputersFromCabinet(Long id) {
+        if ((Object)id == null) {
+            throw new IllegalArgumentException("Cabinet id is null or empty");
+        }
+        return findCabinet(id).getComputers();
+    }
+    @Transactional
+    public void addComputerToCabinet(Long computerId, Long cabinetId) {
+        if ((Object)computerId == null) {
+            throw new IllegalArgumentException("Computer id is null or empty");
+        }
+        if ((Object)cabinetId == null) {
+            throw new IllegalArgumentException("Cabinet id is null or empty");
+        }
+        final Computer computer = computerService.findComputer(computerId);
+        final Cabinet cabinet = findCabinet(cabinetId);
+        cabinet.addComputer(computer);
+    }
+    @Transactional
+    public void deleteComputerFromCabinet(Long computerId, Long cabinetId) {
+        if ((Object) computerId == null) {
+            throw new IllegalArgumentException("Computer id is null or empty");
+        }
+        if ((Object) cabinetId == null) {
+            throw new IllegalArgumentException("Cabinet id is null or empty");
+        }
+        final Computer computer = computerService.findComputer(computerId);
+        final Cabinet cabinet = findCabinet(cabinetId);
+        cabinet.removeComputer(computer);
+    }
+}

backend/src/main/java/com/kalyshev/yan/computer/controller/ComputerController.java

@@ -0,0 +1,56 @@
+package com.kalyshev.yan.computer.controller;
+
+import com.kalyshev.yan.WebConfiguration;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.monitor.controller.MonitorDto;
+import jakarta.validation.Valid;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping(WebConfiguration.REST_API + "/computer")
+public class ComputerController {
+    private final ComputerService computerService;
+    public ComputerController(ComputerService computerService) {
+        this.computerService = computerService;
+    }
+    @GetMapping("/{id}")
+    public ComputerDto getStudent(@PathVariable Long id) {
+        return new ComputerDto(computerService.findComputer(id));
+    }
+    @GetMapping("/")
+    public List<ComputerDto> getComputers() {
+        return computerService.findAllComputers().stream()
+                .map(ComputerDto::new)
+                .toList();
+    }
+    @GetMapping("/filter")
+    public List<ComputerDto> getFilteredComputers(@RequestParam(value = "id", required = false) Long id,
+                                                 @RequestParam(value = "modelName", required = false) String modelName,
+                                                 @RequestParam(value = "serialNum", required = false) String serialNum,
+                                                 @RequestParam(value = "monitorId", required = false) Long monitorId,
+                                                 @RequestParam(value = "cabinetId", required = false) Long cabinetId) {
+        return computerService.findFilteredComputers(id, modelName, serialNum, monitorId, cabinetId).stream()
+                .map(ComputerDto::new)
+                .toList();
+    }
+    @PostMapping("/")
+    public ComputerDto createComputer(@RequestBody @Valid ComputerDto computerDto) {
+        return new ComputerDto(computerService.addComputer(computerDto.getModelName(), computerDto.getSerialNum(), computerDto.getMonitorId()));
+    }
+    @PostMapping("/{id}/monitor")
+    public MonitorDto setMonitorComputer(@PathVariable Long id,
+                                         @RequestParam("monitorId") Long monitorId) {
+        return new MonitorDto(computerService.setMonitor(monitorId, id));
+    }
+    @PutMapping("/{id}")
+    public ComputerDto updateComputer(@PathVariable Long id,
+                                   @RequestBody @Valid ComputerDto computerDto) {
+        return new ComputerDto(computerService.updateComputer(id, computerDto.getModelName(), computerDto.getSerialNum(), computerDto.getMonitorId(), computerDto.getCabinetId()));
+    }
+    @DeleteMapping("/{id}")
+    public ComputerDto deleteComputer(@PathVariable Long id) {
+        return new ComputerDto(computerService.deleteComputer(id));
+    }
+}

backend/src/main/java/com/kalyshev/yan/computer/controller/ComputerDto.java

@@ -0,0 +1,36 @@
+package com.kalyshev.yan.computer.controller;
+
+import com.kalyshev.yan.computer.model.Computer;
+
+public class ComputerDto {
+    private Long id;
+    private String modelName;
+    private String serialNum;
+    private Long monitorId;
+    private Long cabinetId;
+    public ComputerDto() {}
+    public ComputerDto(Computer computer) {
+        this.id = computer.getId();
+        this.modelName = computer.getModelName();
+        this.serialNum = computer.getSerialNum();
+        if (computer.getMonitor() == null) {
+            this.monitorId = null;
+        } else {
+            this.monitorId = computer.getMonitor().getId();
+        }
+        if (computer.getCabinet() == null) {
+            this.cabinetId = null;
+        } else {
+            this.cabinetId = computer.getCabinet().getId();
+        }
+    }
+    public Long getId() { return this.id; }
+    public String getModelName() { return this.modelName; }
+    public void setModelName(String modelName) { this.modelName = modelName; }
+    public String getSerialNum() { return this.serialNum; }
+    public void setSerialNum(String serialNum) { this.serialNum = serialNum; }
+    public Long getMonitorId() { return this.monitorId; }
+    public void setMonitorId(Long monitorId) { this.monitorId = monitorId; }
+    public Long getCabinetId() { return this.cabinetId; }
+    public void setCabinetId(Long cabinetId) { this.cabinetId = cabinetId; }
+}

backend/src/main/java/com/kalyshev/yan/computer/model/Computer.java

@@ -0,0 +1,81 @@
+package com.kalyshev.yan.computer.model;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.monitor.model.Monitor;
+import jakarta.persistence.*;
+
+import java.util.Objects;
+
+@Entity
+@Table(name = "computer")
+public class Computer {
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String modelName;
+    private String serialNum;
+    @ManyToOne( cascade = {CascadeType.MERGE}, fetch = FetchType.EAGER)
+    @JoinColumn(name = "cabinet", nullable = true)
+    private Cabinet cabinet;
+    @OneToOne(cascade = {CascadeType.MERGE})
+    @JoinColumn(name = "monitor_id")
+    private Monitor monitor;
+
+    public Computer() {
+    }
+    public Computer(String modelName, String serialNum) {
+        this.modelName = modelName;
+        this.serialNum = serialNum;
+    }
+
+    public Long getId() {
+        return id;
+    }
+    public String getModelName() {
+        return modelName;
+    }
+    public void setModelName(String modelName) {
+        this.modelName = modelName;
+    }
+    public String getSerialNum() {
+        return serialNum;
+    }
+    public void setSerialNum(String serialNum) { this.serialNum = serialNum; }
+    public Cabinet getCabinet() {
+        return cabinet;
+    }
+    public void setCabinet(Cabinet cabinet) { this.cabinet = cabinet; }
+
+    public Monitor getMonitor() {
+        return monitor;
+    }
+    public void setMonitor(Monitor monitor) {
+        this.monitor = monitor;
+    }
+    public Monitor removeMonitor() {
+        Monitor temp = this.monitor;
+        this.monitor = null;
+        return temp;
+    }
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (!(o instanceof Computer))
+            return false;
+        Computer computer = (Computer) o;
+        return Objects.equals(id, computer.id) && Objects.equals(this.modelName, computer.modelName) && Objects.equals(this.monitor, computer.monitor) && Objects.equals(this.cabinet, computer.cabinet);
+    }
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+    @Override
+    public String toString() {
+        return "Computer{" +
+                "id=" + id +
+                ", modelName='" + modelName + '\'' +
+                ", serialNum='" + serialNum + '\'' +
+                '}';
+    }
+}

backend/src/main/java/com/kalyshev/yan/computer/repository/ComputerNotFoundException.java

@@ -0,0 +1,7 @@
+package com.kalyshev.yan.computer.repository;
+
+public class ComputerNotFoundException extends RuntimeException {
+    public ComputerNotFoundException(Long id) {
+        super(String.format("Computer with id [%s] is not found", id));
+    }
+}

backend/src/main/java/com/kalyshev/yan/computer/repository/ComputerRepository.java

@@ -0,0 +1,34 @@
+package com.kalyshev.yan.computer.repository;
+
+import com.kalyshev.yan.computer.model.Computer;
+import com.kalyshev.yan.monitor.model.Monitor;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Modifying;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+
+import java.util.Collection;
+import java.util.List;
+
+public interface ComputerRepository extends JpaRepository<Computer, Long> {
+    @Query(value = "select * from Computer where (\"ID\" = :id or :id is Null) and " +
+            "(\"MODEL_NAME\" = :modelName or :modelName is Null) and " +
+            "(\"SERIAL_NUM\" = :serialNum or :serialNum is Null) and " +
+            "(\"MONITOR_ID\" = :monitorId or :monitorId is Null) and " +
+            "(\"CABINET\" = :cabinetId or :cabinetId is Null)", nativeQuery = true)
+    public List<Computer> findFilteredComputers(@Param("id") Long id,
+                                                @Param("modelName") String modelName,
+                                                @Param("serialNum") String serialNum,
+                                                @Param("monitorId") Long monitorId,
+                                                @Param("cabinetId") Long cabinetId);
+
+    @Query(value = "select * from Computer where \"MONITOR_ID\" = :monitorId", nativeQuery = true)
+    public Computer findComputerByMonitor(@Param("monitorId") Long monitorId);
+
+    @Modifying
+    @Query(value = "update Computer set \"MONITOR_ID\" = null", nativeQuery = true)
+    public void removeAllComputerMonitorRelations();
+
+//    @Query(value = "update Computer where id in :computerIds set cabinet_id = null")
+//    public void deleteRelationsWithCabinets(@Param("computerIds") Collection<Long> computerIds);
+}

backend/src/main/java/com/kalyshev/yan/computer/service/ComputerService.java

@@ -0,0 +1,135 @@
+package com.kalyshev.yan.computer.service;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.computer.model.Computer;
+import com.kalyshev.yan.computer.repository.ComputerNotFoundException;
+import com.kalyshev.yan.computer.repository.ComputerRepository;
+import com.kalyshev.yan.monitor.model.Monitor;
+import com.kalyshev.yan.monitor.service.MonitorService;
+import com.kalyshev.yan.util.validation.ValidatorUtil;
+import jakarta.annotation.Nullable;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.util.StringUtils;
+
+import java.util.*;
+
+@Service
+public class ComputerService {
+    private final ComputerRepository computerRepository;
+    private final MonitorService monitorService;
+    private final ValidatorUtil validatorUtil;
+    public ComputerService(ComputerRepository computerRepository,
+                           MonitorService monitorService,
+                           ValidatorUtil validatorUtil) {
+        this.computerRepository = computerRepository;
+        this.monitorService = monitorService;
+        this.validatorUtil = validatorUtil;
+    }
+    @Transactional
+    public Computer addComputer(String modelName, String serialNum, @Nullable Long monitorId) {
+        if (!StringUtils.hasText(modelName)) {
+            throw new IllegalArgumentException("Computer model name is null or empty");
+        }
+        if (!StringUtils.hasText(serialNum)) {
+            throw new IllegalArgumentException("Computer serial number is null or empty");
+        }
+        final Computer computer = new Computer(modelName, serialNum);
+        if (monitorId != null) {
+            final Monitor monitor = monitorService.findMonitor(monitorId);
+            computer.setMonitor(monitor);
+        }
+        validatorUtil.validate(computer);
+        return computerRepository.save(computer);
+    }
+    @Transactional(readOnly = true)
+    public Computer findComputer(Long id) {
+        final Optional<Computer> computer = computerRepository.findById(id);
+        return computer.orElseThrow(() -> new ComputerNotFoundException(id));
+    }
+    @Transactional(readOnly = true)
+    public List<Computer> findAllComputers() {
+        return computerRepository.findAll();
+    }
+    @Transactional(readOnly = true)
+    public List<Computer> findFilteredComputers(Long id, String modelName, String serialNum, Long monitorId, Long cabinetId) {
+        return computerRepository.findFilteredComputers(id, modelName, serialNum, monitorId, cabinetId);
+    }
+    @Transactional
+    public Computer updateComputer(Long id, String modelName, String serialNum, Long monitorId, Long cabinetId) {
+        if (!(StringUtils.hasText(modelName) || StringUtils.hasText(serialNum))) {
+            throw new IllegalArgumentException("Need at least one argument");
+        }
+        final Computer currentComputer = findComputer(id);
+        if (modelName != null) {
+            currentComputer.setModelName(modelName);
+        }
+        if (serialNum != null) {
+            currentComputer.setSerialNum(serialNum);
+        }
+        if (monitorId != null) {
+            final Monitor monitor = monitorService.findMonitor(monitorId);
+            currentComputer.setMonitor(monitor);
+        }
+        validatorUtil.validate(currentComputer);
+        return computerRepository.save(currentComputer);
+    }
+    @Transactional
+    public Computer deleteComputer(Long id) {
+        final Computer currentComputer = findComputer(id);
+        Cabinet currentComputerCabinet = currentComputer.getCabinet();
+        if (currentComputerCabinet != null) {
+            currentComputerCabinet.removeComputer(currentComputer);
+        }
+        computerRepository.delete(currentComputer);
+        return currentComputer;
+    }
+    @Transactional
+    public void deleteAllComputers() {
+        List<Computer> computers = findAllComputers();
+        for (Computer computer : computers) {
+            deleteComputer(computer.getId());
+        }
+    }
+    @Transactional
+    public Monitor setMonitor(Long monitorId, Long computerId) {
+        if ((Object)computerId == null) {
+            throw new IllegalArgumentException("Computer id is null or empty");
+        }
+        if ((Object)monitorId == null) {
+            throw new IllegalArgumentException("Monitor id is null or empty");
+        }
+        final Computer computer = findComputer(computerId);
+        final Monitor monitor = monitorService.findMonitor(monitorId);
+        computer.setMonitor(monitor);
+        return monitor;
+    }
+    @Transactional
+    public void deleteRelationsWithCabinets(List<Computer> computers) {
+        for (Computer computer: computers) {
+            computer.setCabinet(null);
+        }
+    }
+    @Transactional
+    public Computer findComputerByMonitor(Monitor monitor) {
+        if (monitor.getId() == null) {
+            return null;
+        }
+        return computerRepository.findComputerByMonitor(monitor.getId());
+    }
+    @Transactional
+    public Monitor deleteMonitorWithRelation(Long id) {
+        final Monitor currentMonitor = monitorService.findMonitor(id);
+        Computer computer = findComputerByMonitor(currentMonitor);
+        if (computer != null) {
+            computer.removeMonitor();
+        }
+        monitorService.deleteMonitor(currentMonitor);
+        return currentMonitor;
+    }
+    @Transactional
+    public void deleteAllMonitorsWithRelations() {
+        computerRepository.removeAllComputerMonitorRelations();
+        monitorService.deleteAllMonitors();
+    }
+}

backend/src/main/java/com/kalyshev/yan/monitor/controller/MonitorController.java

@@ -0,0 +1,51 @@
+package com.kalyshev.yan.monitor.controller;
+
+import com.kalyshev.yan.WebConfiguration;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.monitor.service.MonitorService;
+import jakarta.validation.Valid;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping(WebConfiguration.REST_API + "/monitor")
+public class MonitorController {
+    private final MonitorService monitorService;
+    private final ComputerService computerService;
+    public MonitorController(MonitorService monitorService,
+                             ComputerService computerService) {
+        this.monitorService = monitorService;
+        this.computerService = computerService;
+    }
+    @GetMapping("/{id}")
+    public MonitorDto getMonitor(@PathVariable Long id) {
+        return new MonitorDto(monitorService.findMonitor(id));
+    }
+    @GetMapping("/")
+    public List<MonitorDto> getMonitors() {
+        return monitorService.findAllMonitors().stream()
+                .map(MonitorDto::new)
+                .toList();
+    }
+    @GetMapping("/filter")
+    public List<MonitorDto> getFilteredmonitors(@RequestParam(value = "id", required = false) Long id,
+                                                 @RequestParam(value = "modelName", required = false) String modelName) {
+        return monitorService.findFilteredMonitors(id, modelName).stream()
+                .map(MonitorDto::new)
+                .toList();
+    }
+    @PostMapping("/")
+    public MonitorDto createMonitor(@RequestBody @Valid MonitorDto monitorDto) {
+        return new MonitorDto(monitorService.addMonitor(monitorDto.getModelName()));
+    }
+    @PutMapping("/{id}")
+    public MonitorDto updateMonitor(@PathVariable Long id,
+                                 @RequestBody @Valid MonitorDto monitorDto) {
+        return new MonitorDto(monitorService.updateMonitor(id, monitorDto.getModelName()));
+    }
+    @DeleteMapping("/{id}")
+    public MonitorDto deleteMonitor(@PathVariable Long id) {
+        return new MonitorDto(computerService.deleteMonitorWithRelation(id));
+    }
+}

backend/src/main/java/com/kalyshev/yan/monitor/controller/MonitorDto.java

@@ -0,0 +1,23 @@
+package com.kalyshev.yan.monitor.controller;
+
+import com.kalyshev.yan.monitor.model.Monitor;
+
+public class MonitorDto {
+    private Long id;
+    private String modelName;
+    public MonitorDto() {
+    }
+    public MonitorDto(Monitor monitor) {
+        this.id = monitor.getId();
+        this.modelName = monitor.getModelName();
+    }
+    public Long getId() {
+        return id;
+    }
+    public String getModelName() {
+        return modelName;
+    }
+    public void setModelName(String modelName) {
+        this.modelName = modelName;
+    }
+}

backend/src/main/java/com/kalyshev/yan/monitor/model/Monitor.java

@@ -0,0 +1,51 @@
+package com.kalyshev.yan.monitor.model;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+
+import java.util.Objects;
+
+@Entity
+@Table(name = "monitor")
+public class Monitor {
+    @Id
+    @GeneratedValue
+    private Long id;
+    private String modelName;
+    public Monitor() {
+    }
+    public Monitor(String modelName) {
+        this.modelName = modelName;
+    }
+    public Long getId() {
+        return id;
+    }
+    public String getModelName() {
+        return modelName;
+    }
+    public void setModelName(String modelName) {
+        this.modelName = modelName;
+    }
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (!(o instanceof Monitor))
+            return false;
+        Monitor monitor = (Monitor) o;
+        return Objects.equals(id, monitor.id) && Objects.equals(this.modelName, monitor.modelName);
+    }
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+    @Override
+    public String toString() {
+        return "Monitor{" +
+                "id=" + id +
+                ", modelName='" + modelName + '\'' +
+                '}';
+    }
+}

backend/src/main/java/com/kalyshev/yan/monitor/repository/MonitorNotFoundException.java

@@ -0,0 +1,7 @@
+package com.kalyshev.yan.monitor.repository;
+
+public class MonitorNotFoundException extends RuntimeException {
+    public MonitorNotFoundException(Long id) {
+        super(String.format("Monitor with id [%s] is not found", id));
+    }
+}

backend/src/main/java/com/kalyshev/yan/monitor/repository/MonitorRepository.java

@@ -0,0 +1,15 @@
+package com.kalyshev.yan.monitor.repository;
+
+import com.kalyshev.yan.monitor.model.Monitor;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+
+import java.util.List;
+
+public interface MonitorRepository extends JpaRepository<Monitor, Long> {
+    @Query(value = "select * from Monitor where (\"ID\" = :id or :id is Null) and " +
+            "(\"MODEL_NAME\" = :modelName or :modelName is Null)", nativeQuery = true)
+    public List<Monitor> findFilteredMonitors(@Param("id") Long id,
+                                              @Param("modelName") String modelName);
+}

backend/src/main/java/com/kalyshev/yan/monitor/service/MonitorService.java

@@ -0,0 +1,63 @@
+package com.kalyshev.yan.monitor.service;
+
+import com.kalyshev.yan.monitor.model.Monitor;
+import com.kalyshev.yan.monitor.repository.MonitorNotFoundException;
+import com.kalyshev.yan.monitor.repository.MonitorRepository;
+import com.kalyshev.yan.util.validation.ValidatorUtil;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.util.StringUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+
+@Service
+public class MonitorService {
+    private final MonitorRepository monitorRepository;
+    private final ValidatorUtil validatorUtil;
+    public MonitorService(MonitorRepository monitorRepository,
+                          ValidatorUtil validatorUtil) {
+        this.monitorRepository = monitorRepository;
+        this.validatorUtil = validatorUtil;
+    }
+    @Transactional
+    public Monitor addMonitor(String modelName) {
+        if (!StringUtils.hasText(modelName)) {
+            throw new IllegalArgumentException("Monitor model name is null or empty");
+        }
+        final Monitor monitor = new Monitor(modelName);
+        validatorUtil.validate(monitor);
+        return monitorRepository.save(monitor);
+    }
+    @Transactional(readOnly = true)
+    public Monitor findMonitor(Long id) {
+        final Optional<Monitor> monitor = monitorRepository.findById(id);
+        return monitor.orElseThrow(() -> new MonitorNotFoundException(id));
+    }
+    @Transactional(readOnly = true)
+    public List<Monitor> findAllMonitors() {
+        return monitorRepository.findAll();
+    }
+    @Transactional(readOnly = true)
+    public List<Monitor> findFilteredMonitors(Long id, String modelName) {
+        return monitorRepository.findFilteredMonitors(id, modelName);
+    }
+    @Transactional
+    public Monitor updateMonitor(Long id, String modelName) {
+        if (!StringUtils.hasText(modelName)) {
+            throw new IllegalArgumentException("Monitor model name is null or empty");
+        }
+        final Monitor currentMonitor = findMonitor(id);
+        currentMonitor.setModelName(modelName);
+        validatorUtil.validate(currentMonitor);
+        return monitorRepository.save(currentMonitor);
+    }
+    @Transactional
+    public void deleteMonitor(Monitor monitor) {
+        monitorRepository.delete(monitor);
+    }
+    @Transactional
+    public void deleteAllMonitors() { monitorRepository.deleteAll(); }
+}

backend/src/main/java/com/kalyshev/yan/util/error/AdviceController.java

@@ -0,0 +1,37 @@
+package com.kalyshev.yan.util.error;
+
+import com.kalyshev.yan.cabinet.repository.CabinetNotFoundException;
+import com.kalyshev.yan.util.validation.ValidationException;
+import org.springframework.context.support.DefaultMessageSourceResolvable;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.stream.Collectors;
+
+@ControllerAdvice(annotations = RestController.class)
+public class AdviceController {
+    @ExceptionHandler({
+            CabinetNotFoundException.class,
+            ValidationException.class
+    })
+    public ResponseEntity<Object> handleException(Throwable e) {
+        return new ResponseEntity<>(e.getMessage(), HttpStatus.BAD_REQUEST);
+    }
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<Object> handleBindException(MethodArgumentNotValidException e) {
+        final ValidationException validationException = new ValidationException(
+                e.getBindingResult().getAllErrors().stream()
+                        .map(DefaultMessageSourceResolvable::getDefaultMessage)
+                        .collect(Collectors.toSet()));
+        return handleException(validationException);
+    }
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<Object> handleUnknownException(Throwable e) {
+        e.printStackTrace();
+        return new ResponseEntity<>(e.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
+    }
+}

backend/src/main/java/com/kalyshev/yan/util/validation/ValidationException.java

@@ -0,0 +1,9 @@
+package com.kalyshev.yan.util.validation;
+
+import java.util.Set;
+
+public class ValidationException extends RuntimeException {
+    public <T> ValidationException(Set<String> errors) {
+        super(String.join("\n", errors));
+    }
+}

backend/src/main/java/com/kalyshev/yan/util/validation/ValidatorUtil.java

@@ -0,0 +1,25 @@
+package com.kalyshev.yan.util.validation;
+
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Validation;
+import jakarta.validation.Validator;
+import org.springframework.stereotype.Component;
+
+import java.util.Set;
+import java.util.stream.Collectors;
+
+@Component
+public class ValidatorUtil {
+    private final Validator validator;
+    public ValidatorUtil() {
+        this.validator = Validation.buildDefaultValidatorFactory().getValidator();
+    }
+    public <T> void validate(T object) {
+        final Set<ConstraintViolation<T>> errors = validator.validate(object);
+        if (!errors.isEmpty()) {
+            throw new ValidationException(errors.stream()
+                    .map(ConstraintViolation::getMessage)
+                    .collect(Collectors.toSet()));
+        }
+    }
+}

backend/src/main/resources/application.properties

@@ -0,0 +1,11 @@
+spring.main.banner-mode=off
+#server.port=8080
+spring.datasource.url=jdbc:h2:file:./data
+spring.datasource.driverClassName=org.h2.Driver
+spring.datasource.username=sa
+spring.datasource.password=password
+spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
+spring.jpa.hibernate.ddl-auto=update
+spring.h2.console.enabled=true
+spring.h2.console.settings.trace=false
+spring.h2.console.settings.web-allow-others=false

backend/src/test/java/com/kalyshev/yan/JpaCabinetTests.java

@@ -0,0 +1,64 @@
+package com.kalyshev.yan;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.cabinet.repository.CabinetNotFoundException;
+import com.kalyshev.yan.cabinet.service.CabinetService;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.monitor.service.MonitorService;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import java.util.List;
+
+@SpringBootTest
+public class JpaCabinetTests {
+    private static final Logger log = LoggerFactory.getLogger(JpaCabinetTests.class);
+    @Autowired
+    private ComputerService computerService;
+    @Autowired
+    private MonitorService monitorService;
+    @Autowired
+    private CabinetService cabinetService;
+
+    @Test
+    void testCabinetCreate() {
+        cabinetService.deleteAllCabinets();
+        final Cabinet cabinet = cabinetService.addCabinet("18");
+        log.info(cabinet.toString());
+        Assertions.assertNotNull(cabinet.getId());
+    }
+    @Test
+    void testCabinetRead() {
+        cabinetService.deleteAllCabinets();
+        final Cabinet cabinet = cabinetService.addCabinet("18");
+        log.info(cabinet.toString());
+        final Cabinet findCabinet = cabinetService.findCabinet(cabinet.getId());
+        log.info(findCabinet.toString());
+        Assertions.assertEquals(cabinet, findCabinet);
+    }
+    @Test
+    void testCabinetReadNotFound() {
+        cabinetService.deleteAllCabinets();
+        Assertions.assertThrows(CabinetNotFoundException.class, () -> cabinetService.findCabinet(-1L));
+    }
+    @Test
+    void testCabinetReadAll() {
+        cabinetService.deleteAllCabinets();
+        cabinetService.addCabinet("18");
+        cabinetService.addCabinet("19");
+        final List<Cabinet> cabinets = cabinetService.findAllCabinets();
+        log.info(cabinets.toString());
+        Assertions.assertEquals(cabinets.size(), 2);
+    }
+    @Test
+    void testComputerReadAllEmpty() {
+        cabinetService.deleteAllCabinets();
+        final List<Cabinet> cabinets = cabinetService.findAllCabinets();
+        log.info(cabinets.toString());
+        Assertions.assertEquals(cabinets.size(), 0);
+    }
+}

backend/src/test/java/com/kalyshev/yan/JpaComputerCabinetTests.java

@@ -0,0 +1,85 @@
+package com.kalyshev.yan;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.cabinet.service.CabinetService;
+import com.kalyshev.yan.computer.model.Computer;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.monitor.model.Monitor;
+import com.kalyshev.yan.monitor.service.MonitorService;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+public class JpaComputerCabinetTests {
+    private static final Logger log = LoggerFactory.getLogger(JpaCabinetTests.class);
+    @Autowired
+    private ComputerService computerService;
+    @Autowired
+    private MonitorService monitorService;
+    @Autowired
+    private CabinetService cabinetService;
+
+    @Test
+    void testCabinetAddOneToMany() {
+        cabinetService.deleteAllCabinets();
+        computerService.deleteAllComputers();
+        computerService.deleteAllMonitorsWithRelations();
+        final Cabinet cabinet = cabinetService.addCabinet("18");
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Computer computer = computerService.addComputer("PC", "78457h", monitor.getId());
+        cabinet.addComputer(computer);
+        log.info(cabinet.toString());
+        log.info(computer.toString());
+        Assertions.assertEquals(cabinet.getComputers().get(0).getSerialNum(), computer.getSerialNum());
+    }
+
+    @Test
+    void testCabinetDeleteOneToMany() {
+        cabinetService.deleteAllCabinets();
+        computerService.deleteAllComputers();
+        computerService.deleteAllMonitorsWithRelations();
+        final Cabinet cabinet = cabinetService.addCabinet("18");
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Computer computer = computerService.addComputer("PC", "78457h", monitor.getId());
+        cabinet.addComputer(computer);
+        log.info(cabinet.toString());
+        log.info(computer.toString());
+        Assertions.assertEquals(cabinet.getComputers().get(0).getSerialNum(), computer.getSerialNum());
+        cabinet.removeComputer(computer);
+        Assertions.assertEquals(cabinet.getComputers().size(), 0);
+    }
+
+    @Test
+    void testComputerAddManyToMany() {
+        cabinetService.deleteAllCabinets();
+        computerService.deleteAllComputers();
+        computerService.deleteAllMonitorsWithRelations();
+        final Cabinet cabinet = cabinetService.addCabinet("18");
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Computer computer = computerService.addComputer("PC", "78457h", monitor.getId());
+        computer.setCabinet(cabinet);
+        log.info(cabinet.toString());
+        log.info(computer.toString());
+        Assertions.assertEquals(computer.getCabinet().getNumber(), cabinet.getNumber());
+    }
+
+    @Test
+    void testComputerDeleteManyToMany() {
+        cabinetService.deleteAllCabinets();
+        computerService.deleteAllComputers();
+        computerService.deleteAllMonitorsWithRelations();
+        final Cabinet cabinet = cabinetService.addCabinet("18");
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Computer computer = computerService.addComputer("PC", "78457h", monitor.getId());
+        computer.setCabinet(cabinet);
+        log.info(cabinet.toString());
+        log.info(computer.toString());
+        Assertions.assertEquals(computer.getCabinet().getNumber(), cabinet.getNumber());
+        computer.setCabinet(null);
+        Assertions.assertNull(computer.getCabinet());
+    }
+}

backend/src/test/java/com/kalyshev/yan/JpaComputerTests.java

@@ -0,0 +1,89 @@
+package com.kalyshev.yan;
+
+import com.kalyshev.yan.cabinet.model.Cabinet;
+import com.kalyshev.yan.cabinet.service.CabinetService;
+import com.kalyshev.yan.computer.model.Computer;
+import com.kalyshev.yan.computer.repository.ComputerNotFoundException;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.monitor.model.Monitor;
+import com.kalyshev.yan.monitor.service.MonitorService;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import java.util.List;
+
+@SpringBootTest
+public class JpaComputerTests {
+    private static final Logger log = LoggerFactory.getLogger(JpaComputerTests.class);
+    @Autowired
+    private ComputerService computerService;
+    @Autowired
+    private MonitorService monitorService;
+    @Autowired
+    private CabinetService cabinetService;
+
+    @Test
+    void testComputerPartialCreate() {
+        computerService.deleteAllComputers();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Computer computer = computerService.addComputer("Computer", "w7894572", monitor.getId());
+        log.info(computer.toString());
+        Assertions.assertNotNull(computer.getId());
+        Assertions.assertNull(computer.getCabinet());
+    }
+    @Test
+    void testComputerFullCreate() {
+        computerService.deleteAllComputers();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Cabinet cabinet = cabinetService.addCabinet("18a");
+        final Computer computer = computerService.addComputer("Computer", "w7894572", monitor.getId());
+        computer.setCabinet(cabinet);
+        log.info(computer.toString());
+        Assertions.assertNotNull(computer.getId());
+        Assertions.assertEquals(cabinet, computer.getCabinet());
+    }
+    @Test
+    void testComputerDelete() {
+        computerService.deleteAllComputers();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        final Computer computer = computerService.addComputer("Computer", "w7894572", null);
+        log.info(computer.toString());
+        computerService.deleteComputer(computer.getId());
+        Assertions.assertThrows(ComputerNotFoundException.class, () -> computerService.findComputer(computer.getId()));
+    }
+    @Test
+    void testComputerRead() {
+        computerService.deleteAllComputers();
+        final Computer computer = computerService.addComputer("Computer", "w7894572", null);
+        log.info(computer.toString());
+        final Computer findComputer = computerService.findComputer(computer.getId());
+        log.info(findComputer.toString());
+        Assertions.assertEquals(computer, findComputer);
+    }
+    @Test
+    void testComputerReadNotFound() {
+        computerService.deleteAllComputers();
+        Assertions.assertThrows(ComputerNotFoundException.class, () -> computerService.findComputer(-1L));
+    }
+    @Test
+    void testComputerReadAll() {
+        computerService.deleteAllComputers();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        computerService.addComputer("Computer", "w7894572", null);
+        computerService.addComputer("Another comp", "3453s", null);
+        final List<Computer> computers = computerService.findAllComputers();
+        log.info(computers.toString());
+        Assertions.assertEquals(computers.size(), 2);
+    }
+    @Test
+    void testComputerReadAllEmpty() {
+        computerService.deleteAllComputers();
+        final List<Computer> computers = computerService.findAllComputers();
+        log.info(computers.toString());
+        Assertions.assertEquals(computers.size(), 0);
+    }
+}

backend/src/test/java/com/kalyshev/yan/JpaMonitorTests.java

@@ -0,0 +1,78 @@
+package com.kalyshev.yan;
+
+import com.kalyshev.yan.computer.model.Computer;
+import com.kalyshev.yan.computer.service.ComputerService;
+import com.kalyshev.yan.monitor.model.Monitor;
+import com.kalyshev.yan.monitor.repository.MonitorNotFoundException;
+import com.kalyshev.yan.monitor.service.MonitorService;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import java.util.List;
+@SpringBootTest
+public class JpaMonitorTests {
+    private static final Logger log = LoggerFactory.getLogger(JpaMonitorTests.class);
+    @Autowired
+    private MonitorService monitorService;
+    @Autowired
+    private ComputerService computerService;
+    @Test
+    void testMonitorCreate() {
+        computerService.deleteAllMonitorsWithRelations();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        log.info(monitor.toString());
+        Assertions.assertNotNull(monitor.getId());
+    }
+    @Test
+    void testMonitorRead() {
+        computerService.deleteAllMonitorsWithRelations();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        log.info(monitor.toString());
+        final Monitor findMonitor = monitorService.findMonitor(monitor.getId());
+        log.info(findMonitor.toString());
+        Assertions.assertEquals(monitor, findMonitor);
+    }
+    @Test
+    void testMonitorDelete() {
+        computerService.deleteAllMonitorsWithRelations();
+        final Monitor monitor = monitorService.addMonitor("Asus");
+        log.info(monitor.toString());
+        computerService.deleteMonitorWithRelation(monitor.getId());
+        Assertions.assertThrows(MonitorNotFoundException.class, () -> monitorService.findMonitor(monitor.getId()));
+    }
+    @Test
+    void testMonitorReadNotFound() {
+        computerService.deleteAllMonitorsWithRelations();
+        Assertions.assertThrows(MonitorNotFoundException.class, () -> monitorService.findMonitor(-1L));
+    }
+    @Test
+    void testMonitorReadAll() {
+        computerService.deleteAllMonitorsWithRelations();
+        monitorService.addMonitor("Asus");
+        monitorService.addMonitor("HP");
+        final List<Monitor> monitors = monitorService.findAllMonitors();
+        log.info(monitors.toString());
+        Assertions.assertEquals(monitors.size(), 2);
+    }
+    @Test
+    void testMonitorReadAllEmpty() {
+        computerService.deleteAllMonitorsWithRelations();
+        final List<Monitor> monitors = monitorService.findAllMonitors();
+        log.info(monitors.toString());
+        Assertions.assertEquals(monitors.size(), 0);
+    }
+    @Test
+    void testMonitorGetComputer() {
+        computerService.deleteAllMonitorsWithRelations();
+        computerService.deleteAllComputers();
+        Monitor monitor = monitorService.addMonitor("Asus");
+        Computer computer = computerService.addComputer("Model", "6sfv4", monitor.getId());
+        log.info(computer.toString());
+        Computer fetchedComputer = computerService.findComputerByMonitor(monitor);
+        Assertions.assertEquals(computer, fetchedComputer);
+    }
+}