diff --git a/.gitignore b/.gitignore index b63da45..869d741 100644 --- a/.gitignore +++ b/.gitignore @@ -15,6 +15,7 @@ build/ out/ !**/src/main/**/out/ !**/src/test/**/out/ +.idea ### Eclipse ### .apt_generated diff --git a/README.md b/README.md index d7a6ba3..e974d43 100644 --- a/README.md +++ b/README.md @@ -1,3 +1,4 @@ +[![Review Assignment Due Date](https://classroom.github.com/assets/deadline-readme-button-22041afd0340ce965d47ae6ef1cefeee28c7c493a6346c4f15d667ab976d596c.svg)](https://classroom.github.com/a/qcWcnElX) # Java concurrency # Цели и задачи л/р: diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar index 249e583..1b33c55 100644 Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties index febec7a..ca025c8 100644 --- a/gradle/wrapper/gradle-wrapper.properties +++ b/gradle/wrapper/gradle-wrapper.properties @@ -1,6 +1,7 @@ -#Sat Sep 13 12:45:04 MSK 2025 distributionBase=GRADLE_USER_HOME distributionPath=wrapper/dists -distributionUrl=https\://services.gradle.org/distributions/gradle-8.10-bin.zip +distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip +networkTimeout=10000 +validateDistributionUrl=true zipStoreBase=GRADLE_USER_HOME zipStorePath=wrapper/dists diff --git a/gradlew b/gradlew old mode 100644 new mode 100755 index 1b6c787..23d15a9 --- a/gradlew +++ b/gradlew @@ -15,6 +15,8 @@ # See the License for the specific language governing permissions and # limitations under the License. # +# SPDX-License-Identifier: Apache-2.0 +# ############################################################################## # @@ -55,7 +57,7 @@ # 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 +# https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt # within the Gradle project. # # You can find Gradle at https://github.com/gradle/gradle/. @@ -80,13 +82,11 @@ do esac done -APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit - -APP_NAME="Gradle" +# This is normally unused +# shellcheck disable=SC2034 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"' +# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036) +APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit # Use the maximum available, or set MAX_FD != -1 to use that value. MAX_FD=maximum @@ -114,7 +114,7 @@ case "$( uname )" in #( NONSTOP* ) nonstop=true ;; esac -CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar +CLASSPATH="\\\"\\\"" # Determine the Java command to use to start the JVM. @@ -133,22 +133,29 @@ 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. + 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 $MAX_FD" esac @@ -193,18 +200,28 @@ if "$cygwin" || "$msys" ; then 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. + +# 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, 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 \ + -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \ "$@" +# 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. diff --git a/gradlew.bat b/gradlew.bat index 107acd3..db3a6ac 100644 --- a/gradlew.bat +++ b/gradlew.bat @@ -13,8 +13,10 @@ @rem See the License for the specific language governing permissions and @rem limitations under the License. @rem +@rem SPDX-License-Identifier: Apache-2.0 +@rem -@if "%DEBUG%" == "" @echo off +@if "%DEBUG%"=="" @echo off @rem ########################################################################## @rem @rem Gradle startup script for Windows @@ -25,7 +27,8 @@ if "%OS%"=="Windows_NT" setlocal set DIRNAME=%~dp0 -if "%DIRNAME%" == "" set DIRNAME=. +if "%DIRNAME%"=="" set DIRNAME=. +@rem This is normally unused set APP_BASE_NAME=%~n0 set APP_HOME=%DIRNAME% @@ -40,13 +43,13 @@ if defined JAVA_HOME goto findJavaFromJavaHome set JAVA_EXE=java.exe %JAVA_EXE% -version >NUL 2>&1 -if "%ERRORLEVEL%" == "0" goto execute +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. +echo. 1>&2 +echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2 +echo. 1>&2 +echo Please set the JAVA_HOME variable in your environment to match the 1>&2 +echo location of your Java installation. 1>&2 goto fail @@ -56,32 +59,34 @@ 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. +echo. 1>&2 +echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2 +echo. 1>&2 +echo Please set the JAVA_HOME variable in your environment to match the 1>&2 +echo location of your Java installation. 1>&2 goto fail :execute @rem Setup the command line -set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar +set CLASSPATH= @rem Execute Gradle -"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %* +"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* :end @rem End local scope for the variables with windows NT shell -if "%ERRORLEVEL%"=="0" goto mainEnd +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! -if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1 -exit /b 1 +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 diff --git a/src/main/java/org/labs/Bowl.java b/src/main/java/org/labs/Bowl.java new file mode 100644 index 0000000..5c3d004 --- /dev/null +++ b/src/main/java/org/labs/Bowl.java @@ -0,0 +1,20 @@ +package org.labs; + +import java.util.concurrent.atomic.AtomicInteger; + +final class Bowl { + // количество ложек супа, оставшихся в миске + final AtomicInteger remaining = new AtomicInteger(0); + + // долить в миску новую порцию + void fill(int portion) { remaining.addAndGet(portion); } + + // проблем съесть одну ложку + boolean takeOne() { + int cur = remaining.get(); + if (cur <= 0) return false; + return remaining.compareAndSet(cur, cur - 1); + } + + boolean isEmpty() { return remaining.get() == 0; } +} diff --git a/src/main/java/org/labs/Config.java b/src/main/java/org/labs/Config.java new file mode 100644 index 0000000..d2419e4 --- /dev/null +++ b/src/main/java/org/labs/Config.java @@ -0,0 +1,14 @@ +package org.labs; + +import java.time.Duration; + +/** + * @param N number of programmers + * @param W number of waiters + * @param F total portions in stock + * @param thinkMin min thinking time in ms + * @param thinkMax max thinking time in ms + * @param eatMin min eating time in ms + * @param eatMax max eating time in ms + */ +record Config(int N, int W, long F, int bitesInBowl, Duration thinkMin, Duration thinkMax, Duration eatMin, Duration eatMax) {} \ No newline at end of file diff --git a/src/main/java/org/labs/DiningProgrammersSimulation.java b/src/main/java/org/labs/DiningProgrammersSimulation.java new file mode 100644 index 0000000..4ce34b1 --- /dev/null +++ b/src/main/java/org/labs/DiningProgrammersSimulation.java @@ -0,0 +1,101 @@ +package org.labs; + +import java.io.IOException; +import java.io.InputStream; +import java.time.Duration; +import java.util.Arrays; +import java.util.Properties; +import java.util.concurrent.CyclicBarrier; + +public class DiningProgrammersSimulation { + public static SimulationResult runSimulation(Config cfg) throws Exception { + Table table = new Table(cfg); + + // барьер для одновременного старта философов + CyclicBarrier startBarrier = new CyclicBarrier(cfg.N()); + + // официанты + Thread[] waiters = new Thread[cfg.W()]; + for (int id = 0; id < cfg.W(); id++) { + waiters[id] = Thread.startVirtualThread(new Waiter(id, table)); + } + + // программисты + Thread[] programmers = new Thread[cfg.N()]; + for (int i = 0; i < cfg.N(); i++) { + final int id = i; + programmers[i] = Thread.startVirtualThread(() -> { + try { startBarrier.await(); } catch (Exception ignored) {} + new Programmer(id, table).run(); + }); + } + + // ждём логического завершения (еда кончилась и миски пусты) + while (true) { + if (table.isFinished()) { + table.closed.set(true); + break; + } + Thread.sleep(10); + } + + // корректно завершаем официантов + for (int i = 0; i < cfg.W(); i++) { + table.refillQueue.put(Utils.POISON); + } + + // ждём всех + for (Thread t : programmers) t.join(); + for (Thread w : waiters) w.join(); + + return new SimulationResult(table, cfg); + } + + private static Config loadConfig() { + Properties props = new Properties(); + try (InputStream in = DiningProgrammersSimulation.class + .getClassLoader() + .getResourceAsStream("application.properties")) { + + if (in == null) { + throw new RuntimeException("Не найден application.properties в classpath"); + } + props.load(in); + } catch (IOException e) { + throw new RuntimeException("Ошибка чтения application.properties", e); + } + + int N = Integer.parseInt(props.getProperty("N", "7")); + int W = Integer.parseInt(props.getProperty("W", "3")); + long F = Long.parseLong(props.getProperty("F", "5000")); + int bitesInBowl = Integer.parseInt(props.getProperty("bitesInBowl", "1")); + + Duration thinkMin = Duration.ofMillis(Long.parseLong(props.getProperty("thinkMin", "2"))); + Duration thinkMax = Duration.ofMillis(Long.parseLong(props.getProperty("thinkMax", "8"))); + Duration eatMin = Duration.ofMillis(Long.parseLong(props.getProperty("eatMin", "2"))); + Duration eatMax = Duration.ofMillis(Long.parseLong(props.getProperty("eatMax", "6"))); + + return new Config(N, W, F, bitesInBowl, thinkMin, thinkMax, eatMin, eatMax); + } + + public static void main(String[] args) throws Exception { + Config cfg = loadConfig(); + SimulationResult res = runSimulation(cfg); + + // печать результатов + System.out.println("\n=== RESULT ==="); + System.out.printf("Total eaten: %d, stock left: %d (initial %d)%n", + res.totalEaten, res.stockLeft, res.F); + System.out.println("Per programmer portions:"); + for (int i = 0; i < res.N; i++) { + System.out.printf(" #%d: %d%n", i, res.eatenPerProgrammer[i]); + } + long max = Arrays.stream(res.eatenPerProgrammer).max().orElse(0); + long min = Arrays.stream(res.eatenPerProgrammer).min().orElse(0); + double avg = res.N == 0 ? 0 : (double) res.totalEaten / res.N; + double spreadPercent = avg == 0 ? 0 : (double)(max - min) / avg * 100.0; + System.out.printf("Min=%d Max=%d Avg=%.2f Spread=%d, SpreadPercent=%.2f%%%n", + min, max, avg, (max - min), spreadPercent); + System.out.println("Finished."); + } +} diff --git a/src/main/java/org/labs/Main.java b/src/main/java/org/labs/Main.java deleted file mode 100644 index 9917247..0000000 --- a/src/main/java/org/labs/Main.java +++ /dev/null @@ -1,7 +0,0 @@ -package org.labs; - -public class Main { - public static void main(String[] args) { - System.out.println("Hello, World!"); - } -} \ No newline at end of file diff --git a/src/main/java/org/labs/Programmer.java b/src/main/java/org/labs/Programmer.java new file mode 100644 index 0000000..a2a407f --- /dev/null +++ b/src/main/java/org/labs/Programmer.java @@ -0,0 +1,94 @@ +package org.labs; + +import java.util.concurrent.ThreadLocalRandom; + +import static org.labs.Utils.sleepRandom; + +final class Programmer implements Runnable { + final int id; + final Table table; + + Programmer(int id, Table t) { this.id = id; this.table = t; } + + @Override public void run() { + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + Spoon left = table.spoons[id]; + Spoon right = table.spoons[(id + 1) % table.cfg.N()]; + // блокировка по возрастанию id для предотвращения дедлока + Spoon first = left.id < right.id ? left : right; + Spoon second = left.id < right.id ? right : left; + + // начальная порция, если на складе ещё есть еда + ensureBowlHasPortion(); + + while (!table.closed.get() && !Thread.currentThread().isInterrupted()) { + // программист думает перед следующим приёмом пищи + sleepRandom(rnd, table.cfg.thinkMin(), table.cfg.thinkMax()); + + // запрос разрешения у дворецкого (ограничение на N−1 едоков одновременно) + try { + table.butler.acquire(); + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + break; + } + + try { + // берём первую ложку, потом вторую + first.lock.lock(); + try { + second.lock.lock(); + try { + // едим пока есть еда в тарелке + int bites = 0; + while (table.bowls[id].takeOne()) { + table.eaten[id].addAndGet(1); + bites++; + // кушаем ложку + sleepRandom(rnd, table.cfg.eatMin(), table.cfg.eatMax()); + } + // если миска опустела просим официанта долить + if (bites == 0 && !table.closed.get()) { + requestRefill(); + } + } finally { + second.lock.unlock(); + } + } finally { + // освобождаем вторую ложку, потом первую ложку + first.lock.unlock(); + } + } finally { + // отпускаем дворецкого + table.butler.release(); + } + } + } + + // проверяем, есть ли еда в миске, и если нет — сразу запрашиваем доливку + void ensureBowlHasPortion() { + if (!table.closed.get() && table.bowls[id].isEmpty()) { + requestRefill(); + } + } + + // запрос доливки у официанта + void requestRefill() { + if (table.closed.get()) return; + if (!table.refillRequested[id].compareAndSet(false, true)) return; + table.pendingRefills.incrementAndGet(); + RefillRequest req = new RefillRequest(id, table.eaten[id].get(), table.sequence.getAndIncrement()); + try { + // кладём заявку в очередь + table.refillQueue.put(req); + // ждём, пока официант выполнит запрос + boolean ok = req.completed.join(); + if (!ok) { + // официант вернул false — еды на складе не осталось + table.closed.set(true); + } + } finally { + + } + } +} diff --git a/src/main/java/org/labs/RefillRequest.java b/src/main/java/org/labs/RefillRequest.java new file mode 100644 index 0000000..20bd761 --- /dev/null +++ b/src/main/java/org/labs/RefillRequest.java @@ -0,0 +1,24 @@ +package org.labs; + +import java.util.concurrent.CompletableFuture; + +// запрос на долив порции +final class RefillRequest { + final int programmerId; + final long programmerEaten; + final CompletableFuture completed = new CompletableFuture<>(); + final long seq; + RefillRequest(int id, long programmerEaten, long seq) { + this.programmerId = id; + this.programmerEaten = programmerEaten; + this.seq = seq; + } + public int compareTo(RefillRequest o) { + // сначала по количеству съеденного, потом по порядковому номеру заявки + int firstComp = Long.compare(this.programmerEaten, o.programmerEaten); + if (firstComp != 0) { + return firstComp; + } + return Long.compare(this.seq, o.seq); + } +} diff --git a/src/main/java/org/labs/SimulationResult.java b/src/main/java/org/labs/SimulationResult.java new file mode 100644 index 0000000..a58bacd --- /dev/null +++ b/src/main/java/org/labs/SimulationResult.java @@ -0,0 +1,28 @@ +package org.labs; + +import java.util.Arrays; +import java.util.stream.IntStream; + +final class SimulationResult { + public final long[] eatenPerProgrammer; // сколько съел каждый + public final long totalEaten; // сумма съеденного + public final long stockLeft; // остаток на складе + public final boolean closed; // ресторан закрыт по завершении + public final int pendingRefills; // активных заявок не осталось + public final int N; + public final int W; + public final long F; + + public SimulationResult(Table table, Config cfg) { + this.N = cfg.N(); + this.W = cfg.W(); + this.F = cfg.F(); + this.eatenPerProgrammer = IntStream.range(0, cfg.N()) + .mapToLong(i -> table.eaten[i].get()) + .toArray(); + this.totalEaten = Arrays.stream(eatenPerProgrammer).sum(); + this.stockLeft = table.stock.get(); + this.closed = table.closed.get(); + this.pendingRefills = table.pendingRefills.get(); + } +} \ No newline at end of file diff --git a/src/main/java/org/labs/Spoon.java b/src/main/java/org/labs/Spoon.java new file mode 100644 index 0000000..c023c4d --- /dev/null +++ b/src/main/java/org/labs/Spoon.java @@ -0,0 +1,10 @@ +package org.labs; + +import java.util.concurrent.locks.ReentrantLock; + +// уникальная ложка, которую можно залочить +final class Spoon { + final int id; + final ReentrantLock lock = new ReentrantLock(true); // fair = true + Spoon(int id) { this.id = id; } +} \ No newline at end of file diff --git a/src/main/java/org/labs/Table.java b/src/main/java/org/labs/Table.java new file mode 100644 index 0000000..2ba2bdd --- /dev/null +++ b/src/main/java/org/labs/Table.java @@ -0,0 +1,43 @@ +package org.labs; + +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.PriorityBlockingQueue; +import java.util.concurrent.Semaphore; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.atomic.AtomicLong; +import java.util.stream.IntStream; + +// глобальный контекст, по сути сам ресторан +final class Table { + final Config cfg; + final Spoon[] spoons; + final Semaphore butler; // "дворецкий", разрешает максимум N−1 философов одновременно + final PriorityBlockingQueue refillQueue; // очередь заявок на доливку + final AtomicLong stock; // остаток порций на складе + final AtomicBoolean closed = new AtomicBoolean(false); // флаг "ресторан закрыт" + final Bowl[] bowls; // миски философов + final AtomicLong[] eaten; // сколько каждый съел + final AtomicInteger pendingRefills = new AtomicInteger(0); // количество активных заявок + final AtomicBoolean[] refillRequested; // флаг, что философ уже запросил доливку + final AtomicLong sequence = new AtomicLong(0); // для нумерации заявок + + Table(Config cfg) { + this.cfg = cfg; + this.spoons = IntStream.range(0, cfg.N()).mapToObj(Spoon::new).toArray(Spoon[]::new); + this.butler = new Semaphore(Math.max(1, cfg.N() - 1), true); + this.refillQueue = new PriorityBlockingQueue<>(cfg.N() * 2, RefillRequest::compareTo); + this.stock = new AtomicLong(cfg.F()); + this.bowls = IntStream.range(0, cfg.N()).mapToObj(_ -> new Bowl()).toArray(Bowl[]::new); + this.eaten = IntStream.range(0, cfg.N()).mapToObj(_ -> new AtomicLong()).toArray(AtomicLong[]::new); + this.refillRequested = IntStream.range(0, cfg.N()).mapToObj(_ -> new AtomicBoolean(false)).toArray(AtomicBoolean[]::new); + } + + // проверяем, закончилась ли симуляция (еда кончилась и миски пусты) + boolean isFinished() { + if (stock.get() > 0) return false; + if (pendingRefills.get() > 0) return false; + for (Bowl b : bowls) if (!b.isEmpty()) return false; + return true; + } +} \ No newline at end of file diff --git a/src/main/java/org/labs/Utils.java b/src/main/java/org/labs/Utils.java new file mode 100644 index 0000000..69c4013 --- /dev/null +++ b/src/main/java/org/labs/Utils.java @@ -0,0 +1,14 @@ +package org.labs; + +import java.time.Duration; +import java.util.concurrent.ThreadLocalRandom; + +public class Utils { + // "ядовитая" ложка для остановки потоков + static final RefillRequest POISON = new RefillRequest(-1, -1, -1); + + static void sleepRandom(ThreadLocalRandom rnd, Duration min, Duration max) { + long d = rnd.nextLong(min.toMillis(), Math.max(min.toMillis()+1, max.toMillis()+1)); + try { Thread.sleep(d); } catch (InterruptedException ie) { Thread.currentThread().interrupt(); } + } +} diff --git a/src/main/java/org/labs/Waiter.java b/src/main/java/org/labs/Waiter.java new file mode 100644 index 0000000..ceb713d --- /dev/null +++ b/src/main/java/org/labs/Waiter.java @@ -0,0 +1,45 @@ +package org.labs; + +import static org.labs.Utils.POISON; + +// официант: берёт заявки из очереди и доливает суп +final class Waiter implements Runnable { + final int id; + final Table table; + + Waiter(int id, Table t) { this.id = id; this.table = t; } + + @Override public void run() { + try { + for (RefillRequest req = table.refillQueue.take(); req != POISON; req = table.refillQueue.take()) { + int want = table.cfg.bitesInBowl(); + int got = 0; + + while (true) { + long cur = table.stock.get(); + if (cur <= 0) break; + int take = (int) Math.min(cur, want); + if (table.stock.compareAndSet(cur, cur - take)) { + got = take; + break; + } + } + + if (got > 0) { + table.bowls[req.programmerId].fill(got); + req.completed.complete(true); + // если налили неполную миску — склад исчерпан, можно пометить закрытие + if (got < want) table.closed.set(true); + } else { + table.closed.set(true); + req.completed.complete(false); + } + + table.refillRequested[req.programmerId].set(false); + table.pendingRefills.decrementAndGet(); + } + } catch (InterruptedException ie) { + Thread.currentThread().interrupt(); + } + } +} diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties new file mode 100644 index 0000000..6c6ef00 --- /dev/null +++ b/src/main/resources/application.properties @@ -0,0 +1,12 @@ +# programmers +N=7 +# waiters +W=3 +# portions +F=9999 +bitesInBowl=1 + +thinkMin=1 +thinkMax=6 +eatMin=2 +eatMax=6 diff --git a/src/test/java/org/labs/RefillPriorityTest.java b/src/test/java/org/labs/RefillPriorityTest.java new file mode 100644 index 0000000..5ad2cbd --- /dev/null +++ b/src/test/java/org/labs/RefillPriorityTest.java @@ -0,0 +1,40 @@ +package org.labs; + +import org.junit.jupiter.api.Test; + +import java.util.PriorityQueue; + +import static org.junit.jupiter.api.Assertions.*; + +class RefillPriorityTest { + + @Test + void lowerEatenComesFirst() { + RefillRequest a = new RefillRequest(0, 5, 100); + RefillRequest b = new RefillRequest(1, 2, 200); + RefillRequest c = new RefillRequest(2, 7, 300); + + PriorityQueue pq = new PriorityQueue<>(RefillRequest::compareTo); + pq.add(a); pq.add(b); pq.add(c); + + // ожидаем порядок по возрастанию eatenSnapshot: b(2), a(5), c(7) + assertSame(b, pq.poll()); + assertSame(a, pq.poll()); + assertSame(c, pq.poll()); + } + + @Test + void stableOrderWhenEatenEqual_usesSeq() { + // одинаковые eatenSnapshot, разный seq — должен побеждать меньший seq + RefillRequest r1 = new RefillRequest(10, 4, 1); + RefillRequest r2 = new RefillRequest(11, 4, 2); + RefillRequest r3 = new RefillRequest(12, 4, 3); + + PriorityQueue pq = new PriorityQueue<>(RefillRequest::compareTo); + pq.add(r3); pq.add(r1); pq.add(r2); + + assertSame(r1, pq.poll()); + assertSame(r2, pq.poll()); + assertSame(r3, pq.poll()); + } +} diff --git a/src/test/java/org/labs/SimulationTest.java b/src/test/java/org/labs/SimulationTest.java new file mode 100644 index 0000000..0519efc --- /dev/null +++ b/src/test/java/org/labs/SimulationTest.java @@ -0,0 +1,72 @@ +package org.labs; + +import org.junit.jupiter.api.Test; +import org.junit.jupiter.api.Timeout; + +import java.time.Duration; +import java.util.Arrays; + +import static org.junit.jupiter.api.Assertions.*; + +class SimulationResultTest { + + private static Config cfg(int N, int W, long F) { + return new Config( + N, W, F, + 1, + Duration.ofMillis(1), Duration.ofMillis(3), + Duration.ofMillis(1), Duration.ofMillis(2) + ); + } + + @Test + @Timeout(5) + void simulationTerminatesAndKeepsInvariants() throws Exception { + int N = 7, W = 2; + long F = 500; + + SimulationResult res = DiningProgrammersSimulation.runSimulation(cfg(N, W, F)); + + assertTrue(res.closed, "Ресторан должен быть закрыт к окончанию теста"); + + assertEquals(N, res.eatenPerProgrammer.length, "Длина eatenPerProgrammer должна быть N"); + + assertEquals(0, res.pendingRefills, "Не должно остаться активных заявок на доливку"); + + assertTrue(res.stockLeft >= 0, "Остаток на складе не должен быть отрицательным"); + + assertEquals(F - res.stockLeft, res.totalEaten, + "Сумма съеденного должна совпадать с списанным со склада"); + + long sumByPeople = Arrays.stream(res.eatenPerProgrammer).sum(); + assertEquals(res.totalEaten, sumByPeople, "totalEaten должен равняться сумме по участникам"); + } + + @Test + @Timeout(10) + void fairnessSpreadIsReasonableForPriorityRefills() throws Exception { + int N = 7, W = 3; + long F = 5500; + + SimulationResult res = DiningProgrammersSimulation.runSimulation(cfg(N, W, F)); + + long max = Arrays.stream(res.eatenPerProgrammer).max().orElse(0); + long min = Arrays.stream(res.eatenPerProgrammer).min().orElse(0); + double avg = res.N == 0 ? 0.0 : (double) res.totalEaten / res.N; + + // допускаем умеренный спред + double allowedSpread = avg * 0.25; + assertTrue(max - min <= allowedSpread, + String.format("Справедливость: спред слишком большой (min=%d, max=%d, avg=%.2f, spread=%.2f, allowed=%.2f)", + min, max, avg, (double)(max - min), allowedSpread)); + } + + @Test + @Timeout(4) + void smallRunNoDeadlock() throws Exception { + SimulationResult res = DiningProgrammersSimulation.runSimulation(cfg(5, 2, 500)); + + assertTrue(res.closed, "Симуляция должна корректно завершиться"); + assertEquals(0, res.pendingRefills, "Очередь доливок должна быть пустой к концу"); + } +}