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rpvilaorpvilao
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Merge pull request #8758 from mguarnaccia/BAEL-3855
BAEL-3855
2 parents 76b091a + 0692bac commit b5fb4b4

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‎core-java-modules/core-java-concurrency-collections-2/pom.xml‎

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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>com.baeldung.concurrent.lock</groupId>
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<artifactId>core-java-concurrency-collections-2</artifactId>
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<version>0.0.1-SNAPSHOT</version>
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<properties>
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<jmh.version>1.21</jmh.version>
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<guava.version>28.2-jre</guava.version>
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</properties>
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<dependencies>
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<dependency>
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<groupId>com.google.guava</groupId>
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<artifactId>guava</artifactId>
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<version>${guava.version}</version>
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</dependency>
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<dependency>
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<groupId>org.openjdk.jmh</groupId>
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<artifactId>jmh-core</artifactId>
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<version>${jmh.version}</version>
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</dependency>
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<dependency>
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<groupId>org.openjdk.jmh</groupId>
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<artifactId>jmh-generator-annprocess</artifactId>
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<version>${jmh.version}</version>
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</dependency>
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</dependencies>
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<build>
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<sourceDirectory>src</sourceDirectory>
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<plugins>
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<plugin>
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<artifactId>maven-compiler-plugin</artifactId>
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<version>3.8.0</version>
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<configuration>
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<source>1.8</source>
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<target>1.8</target>
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</configuration>
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</plugin>
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</plugins>
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</build>
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</project>

‎core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/ConcurrentAccessBenchmark.java‎

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package com.baeldung.concurrent.lock;
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import java.util.HashMap;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.TimeUnit;
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import java.util.Map;
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import org.openjdk.jmh.annotations.Benchmark;
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import org.openjdk.jmh.annotations.BenchmarkMode;
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import org.openjdk.jmh.annotations.Fork;
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import org.openjdk.jmh.annotations.Mode;
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import org.openjdk.jmh.annotations.OutputTimeUnit;
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import org.openjdk.jmh.annotations.Scope;
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import org.openjdk.jmh.annotations.State;
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import org.openjdk.jmh.annotations.Warmup;
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@State(Scope.Thread)
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@Fork(value = 2)
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@Warmup(iterations = 0)
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public class ConcurrentAccessBenchmark {
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static final int SLOTS = 4;
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static final int THREADS = 10000;
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static final int BUCKETS = Runtime.getRuntime().availableProcessors() * SLOTS;
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SingleLock singleLock = new SingleLock();
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StripedLock stripedLock = new StripedLock(BUCKETS);
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@Benchmark
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@BenchmarkMode(Mode.Throughput)
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@OutputTimeUnit(TimeUnit.MILLISECONDS)
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public Map<String,String> singleLockHashMap() throws InterruptedException {
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return singleLock.doWork(new HashMap<String,String>(), THREADS, SLOTS);
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}
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@Benchmark
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@BenchmarkMode(Mode.Throughput)
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@OutputTimeUnit(TimeUnit.MILLISECONDS)
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public Map<String,String> stripedLockHashMap() throws InterruptedException {
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return stripedLock.doWork(new HashMap<String,String>(), THREADS, SLOTS);
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}
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@Benchmark
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@BenchmarkMode(Mode.Throughput)
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@OutputTimeUnit(TimeUnit.MILLISECONDS)
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public Map<String,String> singleLockConcurrentHashMap() throws InterruptedException {
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return singleLock.doWork(new ConcurrentHashMap<String,String>(), THREADS, SLOTS);
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}
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@Benchmark
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@BenchmarkMode(Mode.Throughput)
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@OutputTimeUnit(TimeUnit.MILLISECONDS)
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public Map<String,String> stripedLockConcurrentHashMap() throws InterruptedException {
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return stripedLock.doWork(new ConcurrentHashMap<String,String>(), THREADS, SLOTS);
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}
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}

‎core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/ConcurrentAccessExperiment.java‎

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package com.baeldung.concurrent.lock;
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import java.util.Map;
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import java.util.concurrent.CompletableFuture;
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import com.google.common.base.Supplier;
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public abstract class ConcurrentAccessExperiment {
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public final Map<String,String> doWork(Map<String,String> map, int threads, int slots) {
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CompletableFuture<?>[] requests = new CompletableFuture<?>[threads * slots];
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for (int i = 0; i < threads; i++) {
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requests[slots * i + 0] = CompletableFuture.supplyAsync(putSupplier(map, i));
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requests[slots * i + 1] = CompletableFuture.supplyAsync(getSupplier(map, i));
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requests[slots * i + 2] = CompletableFuture.supplyAsync(getSupplier(map, i));
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requests[slots * i + 3] = CompletableFuture.supplyAsync(getSupplier(map, i));
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}
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CompletableFuture.allOf(requests).join();
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return map;
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}
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protected abstract Supplier<?> putSupplier(Map<String,String> map, int key);
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protected abstract Supplier<?> getSupplier(Map<String,String> map, int key);
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}

‎core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/SingleLock.java‎

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package com.baeldung.concurrent.lock;
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import java.util.Map;
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import java.util.concurrent.locks.ReentrantLock;
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import com.google.common.base.Supplier;
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public class SingleLock extends ConcurrentAccessExperiment {
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ReentrantLock lock;
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public SingleLock() {
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lock = new ReentrantLock();
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}
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protected Supplier<?> putSupplier(Map<String,String> map, int key) {
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return (()-> {
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lock.lock();
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try {
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return map.put("key" + key, "value" + key);
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} finally {
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lock.unlock();
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}
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});
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}
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protected Supplier<?> getSupplier(Map<String,String> map, int key) {
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return (()-> {
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lock.lock();
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try {
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return map.get("key" + key);
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} finally {
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lock.unlock();
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}
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});
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}
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}

‎core-java-modules/core-java-concurrency-collections-2/src/main/java/com/baeldung/concurrent/lock/StripedLock.java‎

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package com.baeldung.concurrent.lock;
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import java.util.Map;
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import java.util.concurrent.locks.Lock;
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import com.google.common.base.Supplier;
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import com.google.common.util.concurrent.Striped;
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public class StripedLock extends ConcurrentAccessExperiment {
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Striped<Lock> stripedLock;
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public StripedLock(int buckets) {
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stripedLock = Striped.lock(buckets);
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}
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protected Supplier<?> putSupplier(Map<String,String> map, int key) {
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return (()-> {
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int bucket = key % stripedLock.size();
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Lock lock = stripedLock.get(bucket);
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lock.lock();
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try {
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return map.put("key" + key, "value" + key);
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} finally {
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lock.unlock();
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}
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});
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}
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protected Supplier<?> getSupplier(Map<String,String> map, int key) {
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return (()-> {
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int bucket = key % stripedLock.size();
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Lock lock = stripedLock.get(bucket);
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lock.lock();
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try {
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return map.get("key" + key);
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} finally {
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lock.unlock();
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}
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});
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}
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}

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