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Merge branch 'master' of https://github.com/eugenp/tutorials into BAEL-16822

This commit is contained in:
amit2103 2019-08-25 23:08:25 +05:30
parent 5a2809de8b 3a5f594754
commit 88b03226de
10 changed files with 121 additions and 38 deletions
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5
core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGenerator.java
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@ -1,11 +1,12 @@
package com.baeldung.concurrent.mutex;
public class SequenceGenerator {
private int currentValue = 0;
public int getNextSequence() throws InterruptedException {
public int getNextSequence() {
currentValue = currentValue + 1;
Thread.sleep(500);
return currentValue;
}
}

9
core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingMonitor.java
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@ -4,15 +4,16 @@ import com.google.common.util.concurrent.Monitor;
public class SequenceGeneratorUsingMonitor extends SequenceGenerator {
private Monitor monitor = new Monitor();
private Monitor mutex = new Monitor();
@Override
public int getNextSequence() throws InterruptedException {
monitor.enter();
public int getNextSequence() {
mutex.enter();
try {
return super.getNextSequence();
} finally {
monitor.leave();
mutex.leave();
}
}
}

3
core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingReentrantLock.java
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@ -7,7 +7,7 @@ public class SequenceGeneratorUsingReentrantLock extends SequenceGenerator {
private ReentrantLock mutex = new ReentrantLock();
@Override
public int getNextSequence() throws InterruptedException {
public int getNextSequence() {
try {
mutex.lock();
return super.getNextSequence();
@ -15,4 +15,5 @@ public class SequenceGeneratorUsingReentrantLock extends SequenceGenerator {
mutex.unlock();
}
}
}

5
core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingSemaphore.java
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@ -7,12 +7,15 @@ public class SequenceGeneratorUsingSemaphore extends SequenceGenerator {
private Semaphore mutex = new Semaphore(1);
@Override
public int getNextSequence() throws InterruptedException {
public int getNextSequence() {
try {
mutex.acquire();
return super.getNextSequence();
} catch (InterruptedException e) {
throw new RuntimeException("Exception in critical section.", e);
} finally {
mutex.release();
}
}
}

6
core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingSynchronizedBlock.java
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@ -2,9 +2,11 @@ package com.baeldung.concurrent.mutex;
public class SequenceGeneratorUsingSynchronizedBlock extends SequenceGenerator {
private Object mutex = new Object();
@Override
public int getNextSequence() throws InterruptedException {
synchronized (this) {
public int getNextSequence() {
synchronized (mutex) {
return super.getNextSequence();
}
}

2
core-java-modules/core-java-concurrency-basic/src/main/java/com/baeldung/concurrent/mutex/SequenceGeneratorUsingSynchronizedMethod.java
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@ -3,7 +3,7 @@ package com.baeldung.concurrent.mutex;
public class SequenceGeneratorUsingSynchronizedMethod extends SequenceGenerator {
@Override
public synchronized int getNextSequence() throws InterruptedException {
public synchronized int getNextSequence() {
return super.getNextSequence();
}

53
core-java-modules/core-java-concurrency-basic/src/test/java/com/baeldung/concurrent/mutex/MutexUnitTest.java
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@ -1,7 +1,7 @@
package com.baeldung.concurrent.mutex;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ExecutorService;
@ -12,59 +12,58 @@ import java.util.concurrent.TimeUnit;
import org.junit.Assert;
import org.junit.Test;
import com.baeldung.concurrent.mutex.SequenceGenerator;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingMonitor;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingReentrantLock;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingSemaphore;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingSynchronizedBlock;
import com.baeldung.concurrent.mutex.SequenceGeneratorUsingSynchronizedMethod;
public class MutexUnitTest {
private final int RANGE = 30;
@Test
// @Test
// This test verifies the race condition use case, it may pass or fail based on execution environment
// Uncomment @Test to run it
public void givenUnsafeSequenceGenerator_whenRaceCondition_thenUnexpectedBehavior() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGenerator());
Assert.assertNotEquals(RANGE, uniqueSequences.size());
int count = 1000;
Set<Integer> uniqueSequences = getUniqueSequences(new SequenceGenerator(), count);
Assert.assertNotEquals(count, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingSynchronizedMethod_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingSynchronizedMethod());
Assert.assertEquals(RANGE, uniqueSequences.size());
int count = 1000;
Set<Integer> uniqueSequences = getUniqueSequences(new SequenceGeneratorUsingSynchronizedMethod(), count);
Assert.assertEquals(count, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingSynchronizedBlock_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingSynchronizedBlock());
Assert.assertEquals(RANGE, uniqueSequences.size());
int count = 1000;
Set<Integer> uniqueSequences = getUniqueSequences(new SequenceGeneratorUsingSynchronizedBlock(), count);
Assert.assertEquals(count, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingReentrantLock_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingReentrantLock());
Assert.assertEquals(RANGE, uniqueSequences.size());
int count = 1000;
Set<Integer> uniqueSequences = getUniqueSequences(new SequenceGeneratorUsingReentrantLock(), count);
Assert.assertEquals(count, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingSemaphore_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingSemaphore());
Assert.assertEquals(RANGE, uniqueSequences.size());
int count = 1000;
Set<Integer> uniqueSequences = getUniqueSequences(new SequenceGeneratorUsingSemaphore(), count);
Assert.assertEquals(count, uniqueSequences.size());
}
@Test
public void givenSequenceGeneratorUsingMonitor_whenRaceCondition_thenSuccess() throws Exception {
Set<Integer> uniqueSequences = getASetOFUniqueSequences(new SequenceGeneratorUsingMonitor());
Assert.assertEquals(RANGE, uniqueSequences.size());
int count = 1000;
Set<Integer> uniqueSequences = getUniqueSequences(new SequenceGeneratorUsingMonitor(), count);
Assert.assertEquals(count, uniqueSequences.size());
}
private Set<Integer> getASetOFUniqueSequences(SequenceGenerator generator) throws Exception {
private Set<Integer> getUniqueSequences(SequenceGenerator generator, int count) throws Exception {
ExecutorService executor = Executors.newFixedThreadPool(3);
Set<Integer> uniqueSequences = new HashSet<>();
Set<Integer> uniqueSequences = new LinkedHashSet<>();
List<Future<Integer>> futures = new ArrayList<>();
for (int i = 0; i < RANGE; i++) {
for (int i = 0; i < count; i++) {
futures.add(executor.submit(generator::getNextSequence));
}
@ -72,7 +71,7 @@ public class MutexUnitTest {
uniqueSequences.add(future.get());
}
executor.awaitTermination(15, TimeUnit.SECONDS);
executor.awaitTermination(1, TimeUnit.SECONDS);
executor.shutdown();
return uniqueSequences;

50
core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/Employee.java Normal file
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@ -0,0 +1,50 @@
package com.baeldung.core.modifiers;
public class Employee {
private String privateId;
public String name;
private boolean manager;
public Employee(String id, String name) {
changeId(id);
this.name = name;
}
private Employee(String id, String name, boolean managerAttribute) {
this.privateId = id;
this.name = name;
this.privateId = id + "_ID-MANAGER";
}
public void changeId(String customId) {
if (customId.endsWith("_ID")) {
this.privateId = customId;
} else {
this.privateId = customId + "_ID";
}
}
public String getId() {
return privateId;
}
public boolean isManager() {
return manager;
}
public void elevateToManager() {
if ("Carl".equals(this.name)) {
setManager(true);
}
}
private void setManager(boolean manager) {
this.manager = manager;
}
public static Employee buildManager(String id, String name) {
return new Employee(id, name, true);
}
}

10
core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/ExampleClass.java Normal file
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@ -0,0 +1,10 @@
package com.baeldung.core.modifiers;
public class ExampleClass {
public static void main(String[] args) {
Employee employee = new Employee("Bob","ABC123");
employee.changeId("BCD234");
System.out.println(employee.getId());
}
}

16
core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/PublicOuterClass.java Normal file
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@ -0,0 +1,16 @@
package com.baeldung.core.modifiers;
public class PublicOuterClass {
public PrivateInnerClass getInnerClassInstance() {
PrivateInnerClass myPrivateClassInstance = this.new PrivateInnerClass();
myPrivateClassInstance.id = "ID1";
myPrivateClassInstance.name = "Bob";
return myPrivateClassInstance;
}
private class PrivateInnerClass {
public String name;
public String id;
}
}