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[BAEL-8401] - Added new module core-java-concurrency-collections and moved code and github references from core-java-concurrency module

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This commit is contained in:
amit2103
2018-08-19 10:35:26 +05:30
parent c1f4486a27
commit 0a679c1978
35 changed files with 144 additions and 11 deletions
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core-java-concurrency/src/main/java/com/baeldung/concurrent/blockingqueue/BlockingQueueUsage.java
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package com.baeldung.concurrent.blockingqueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
public class BlockingQueueUsage {
public static void main(String[] args) {
int BOUND = 10;
int N_PRODUCERS = 4;
int N_CONSUMERS = Runtime.getRuntime().availableProcessors();
int poisonPill = Integer.MAX_VALUE;
int poisonPillPerProducer = N_CONSUMERS / N_PRODUCERS;
int mod = N_CONSUMERS % N_PRODUCERS;
BlockingQueue<Integer> queue = new LinkedBlockingQueue<>(BOUND);
for (int i = 1; i < N_PRODUCERS; i++) {
new Thread(new NumbersProducer(queue, poisonPill, poisonPillPerProducer)).start();
}
for (int j = 0; j < N_CONSUMERS; j++) {
new Thread(new NumbersConsumer(queue, poisonPill)).start();
}
new Thread(new NumbersProducer(queue, poisonPill, poisonPillPerProducer+mod)).start();
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/blockingqueue/NumbersConsumer.java
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package com.baeldung.concurrent.blockingqueue;
import java.util.concurrent.BlockingQueue;
public class NumbersConsumer implements Runnable {
private final BlockingQueue<Integer> queue;
private final int poisonPill;
NumbersConsumer(BlockingQueue<Integer> queue, int poisonPill) {
this.queue = queue;
this.poisonPill = poisonPill;
}
public void run() {
try {
while (true) {
Integer number = queue.take();
if (number.equals(poisonPill)) {
return;
}
String result = number.toString();
System.out.println(Thread.currentThread().getName() + " result: " + result);
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/blockingqueue/NumbersProducer.java
-36
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package com.baeldung.concurrent.blockingqueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ThreadLocalRandom;
public class NumbersProducer implements Runnable {
private final BlockingQueue<Integer> numbersQueue;
private final int poisonPill;
private final int poisonPillPerProducer;
NumbersProducer(BlockingQueue<Integer> numbersQueue, int poisonPill, int poisonPillPerProducer) {
this.numbersQueue = numbersQueue;
this.poisonPill = poisonPill;
this.poisonPillPerProducer = poisonPillPerProducer;
}
public void run() {
try {
generateNumbers();
} catch (InterruptedException e) {
Thread.currentThread()
.interrupt();
}
}
private void generateNumbers() throws InterruptedException {
for (int i = 0; i < 100; i++) {
numbersQueue.put(ThreadLocalRandom.current()
.nextInt(100));
}
for (int j = 0; j < poisonPillPerProducer; j++) {
numbersQueue.put(poisonPill);
}
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/delayqueue/DelayObject.java
-32
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package com.baeldung.concurrent.delayqueue;
import com.google.common.primitives.Ints;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;
public class DelayObject implements Delayed {
private String data;
private long startTime;
DelayObject(String data, long delayInMilliseconds) {
this.data = data;
this.startTime = System.currentTimeMillis() + delayInMilliseconds;
}
@Override
public long getDelay(TimeUnit unit) {
long diff = startTime - System.currentTimeMillis();
return unit.convert(diff, TimeUnit.MILLISECONDS);
}
@Override
public int compareTo(Delayed o) {
return Ints.saturatedCast(this.startTime - ((DelayObject) o).startTime);
}
@Override
public String toString() {
return "{" + "data='" + data + '\'' + ", startTime=" + startTime + '}';
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/delayqueue/DelayQueueConsumer.java
-30
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package com.baeldung.concurrent.delayqueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.atomic.AtomicInteger;
public class DelayQueueConsumer implements Runnable {
private BlockingQueue<DelayObject> queue;
private final Integer numberOfElementsToTake;
final AtomicInteger numberOfConsumedElements = new AtomicInteger();
DelayQueueConsumer(BlockingQueue<DelayObject> queue, Integer numberOfElementsToTake) {
this.queue = queue;
this.numberOfElementsToTake = numberOfElementsToTake;
}
@Override
public void run() {
for (int i = 0; i < numberOfElementsToTake; i++) {
try {
DelayObject object = queue.take();
numberOfConsumedElements.incrementAndGet();
System.out.println("Consumer take: " + object);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/delayqueue/DelayQueueProducer.java
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package com.baeldung.concurrent.delayqueue;
import java.util.UUID;
import java.util.concurrent.BlockingQueue;
public class DelayQueueProducer implements Runnable {
private BlockingQueue<DelayObject> queue;
private final Integer numberOfElementsToProduce;
private final Integer delayOfEachProducedMessageMilliseconds;
DelayQueueProducer(BlockingQueue<DelayObject> queue,
Integer numberOfElementsToProduce,
Integer delayOfEachProducedMessageMilliseconds) {
this.queue = queue;
this.numberOfElementsToProduce = numberOfElementsToProduce;
this.delayOfEachProducedMessageMilliseconds = delayOfEachProducedMessageMilliseconds;
}
@Override
public void run() {
for (int i = 0; i < numberOfElementsToProduce; i++) {
DelayObject object
= new DelayObject(UUID.randomUUID().toString(), delayOfEachProducedMessageMilliseconds);
System.out.println("Put object = " + object);
try {
queue.put(object);
Thread.sleep(500);
} catch (InterruptedException ie) {
ie.printStackTrace();
}
}
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/locks/ReentrantLockWithCondition.java
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package com.baeldung.concurrent.locks;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Stack;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import static java.lang.Thread.sleep;
public class ReentrantLockWithCondition {
private static Logger LOG = LoggerFactory.getLogger(ReentrantLockWithCondition.class);
private Stack<String> stack = new Stack<>();
private static final int CAPACITY = 5;
private ReentrantLock lock = new ReentrantLock();
private Condition stackEmptyCondition = lock.newCondition();
private Condition stackFullCondition = lock.newCondition();
private void pushToStack(String item) throws InterruptedException {
try {
lock.lock();
if (stack.size() == CAPACITY) {
LOG.info(Thread.currentThread().getName() + " wait on stack full");
stackFullCondition.await();
}
LOG.info("Pushing the item " + item);
stack.push(item);
stackEmptyCondition.signalAll();
} finally {
lock.unlock();
}
}
private String popFromStack() throws InterruptedException {
try {
lock.lock();
if (stack.size() == 0) {
LOG.info(Thread.currentThread().getName() + " wait on stack empty");
stackEmptyCondition.await();
}
return stack.pop();
} finally {
stackFullCondition.signalAll();
lock.unlock();
}
}
public static void main(String[] args) {
final int threadCount = 2;
ReentrantLockWithCondition object = new ReentrantLockWithCondition();
final ExecutorService service = Executors.newFixedThreadPool(threadCount);
service.execute(() -> {
for (int i = 0; i < 10; i++) {
try {
object.pushToStack("Item " + i);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
service.execute(() -> {
for (int i = 0; i < 10; i++) {
try {
LOG.info("Item popped " + object.popFromStack());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
service.shutdown();
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/locks/SharedObjectWithLock.java
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package com.baeldung.concurrent.locks;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;
import static java.lang.Thread.sleep;
public class SharedObjectWithLock {
private static final Logger LOG = LoggerFactory.getLogger(SharedObjectWithLock.class);
private ReentrantLock lock = new ReentrantLock(true);
private int counter = 0;
void perform() {
lock.lock();
LOG.info("Thread - " + Thread.currentThread().getName() + " acquired the lock");
try {
LOG.info("Thread - " + Thread.currentThread().getName() + " processing");
counter++;
} catch (Exception exception) {
LOG.error(" Interrupted Exception ", exception);
} finally {
lock.unlock();
LOG.info("Thread - " + Thread.currentThread().getName() + " released the lock");
}
}
private void performTryLock() {
LOG.info("Thread - " + Thread.currentThread().getName() + " attempting to acquire the lock");
try {
boolean isLockAcquired = lock.tryLock(2, TimeUnit.SECONDS);
if (isLockAcquired) {
try {
LOG.info("Thread - " + Thread.currentThread().getName() + " acquired the lock");
LOG.info("Thread - " + Thread.currentThread().getName() + " processing");
sleep(1000);
} finally {
lock.unlock();
LOG.info("Thread - " + Thread.currentThread().getName() + " released the lock");
}
}
} catch (InterruptedException exception) {
LOG.error(" Interrupted Exception ", exception);
}
LOG.info("Thread - " + Thread.currentThread().getName() + " could not acquire the lock");
}
public ReentrantLock getLock() {
return lock;
}
boolean isLocked() {
return lock.isLocked();
}
boolean hasQueuedThreads() {
return lock.hasQueuedThreads();
}
int getCounter() {
return counter;
}
public static void main(String[] args) {
final int threadCount = 2;
final ExecutorService service = Executors.newFixedThreadPool(threadCount);
final SharedObjectWithLock object = new SharedObjectWithLock();
service.execute(object::perform);
service.execute(object::performTryLock);
service.shutdown();
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/locks/StampedLockDemo.java
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package com.baeldung.concurrent.locks;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.StampedLock;
import static java.lang.Thread.sleep;
public class StampedLockDemo {
private Map<String, String> map = new HashMap<>();
private Logger logger = LoggerFactory.getLogger(StampedLockDemo.class);
private final StampedLock lock = new StampedLock();
public void put(String key, String value) throws InterruptedException {
long stamp = lock.writeLock();
try {
logger.info(Thread.currentThread().getName() + " acquired the write lock with stamp " + stamp);
map.put(key, value);
} finally {
lock.unlockWrite(stamp);
logger.info(Thread.currentThread().getName() + " unlocked the write lock with stamp " + stamp);
}
}
public String get(String key) throws InterruptedException {
long stamp = lock.readLock();
logger.info(Thread.currentThread().getName() + " acquired the read lock with stamp " + stamp);
try {
sleep(5000);
return map.get(key);
} finally {
lock.unlockRead(stamp);
logger.info(Thread.currentThread().getName() + " unlocked the read lock with stamp " + stamp);
}
}
private String readWithOptimisticLock(String key) throws InterruptedException {
long stamp = lock.tryOptimisticRead();
String value = map.get(key);
if (!lock.validate(stamp)) {
stamp = lock.readLock();
try {
sleep(5000);
return map.get(key);
} finally {
lock.unlock(stamp);
logger.info(Thread.currentThread().getName() + " unlocked the read lock with stamp " + stamp);
}
}
return value;
}
public static void main(String[] args) {
final int threadCount = 4;
final ExecutorService service = Executors.newFixedThreadPool(threadCount);
StampedLockDemo object = new StampedLockDemo();
Runnable writeTask = () -> {
try {
object.put("key1", "value1");
} catch (InterruptedException e) {
e.printStackTrace();
}
};
Runnable readTask = () -> {
try {
object.get("key1");
} catch (InterruptedException e) {
e.printStackTrace();
}
};
Runnable readOptimisticTask = () -> {
try {
object.readWithOptimisticLock("key1");
} catch (InterruptedException e) {
e.printStackTrace();
}
};
service.submit(writeTask);
service.submit(writeTask);
service.submit(readTask);
service.submit(readOptimisticTask);
service.shutdown();
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/locks/SynchronizedHashMapWithRWLock.java
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package com.baeldung.concurrent.locks;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import static java.lang.Thread.sleep;
public class SynchronizedHashMapWithRWLock {
private static Map<String, String> syncHashMap = new HashMap<>();
private Logger logger = LoggerFactory.getLogger(SynchronizedHashMapWithRWLock.class);
private final ReadWriteLock lock = new ReentrantReadWriteLock();
private final Lock readLock = lock.readLock();
private final Lock writeLock = lock.writeLock();
public void put(String key, String value) throws InterruptedException {
try {
writeLock.lock();
logger.info(Thread.currentThread().getName() + " writing");
syncHashMap.put(key, value);
sleep(1000);
} finally {
writeLock.unlock();
}
}
public String get(String key) {
try {
readLock.lock();
logger.info(Thread.currentThread().getName() + " reading");
return syncHashMap.get(key);
} finally {
readLock.unlock();
}
}
public String remove(String key) {
try {
writeLock.lock();
return syncHashMap.remove(key);
} finally {
writeLock.unlock();
}
}
public boolean containsKey(String key) {
try {
readLock.lock();
return syncHashMap.containsKey(key);
} finally {
readLock.unlock();
}
}
boolean isReadLockAvailable() {
return readLock.tryLock();
}
public static void main(String[] args) throws InterruptedException {
final int threadCount = 3;
final ExecutorService service = Executors.newFixedThreadPool(threadCount);
SynchronizedHashMapWithRWLock object = new SynchronizedHashMapWithRWLock();
service.execute(new Thread(new Writer(object), "Writer"));
service.execute(new Thread(new Reader(object), "Reader1"));
service.execute(new Thread(new Reader(object), "Reader2"));
service.shutdown();
}
private static class Reader implements Runnable {
SynchronizedHashMapWithRWLock object;
Reader(SynchronizedHashMapWithRWLock object) {
this.object = object;
}
@Override
public void run() {
for (int i = 0; i < 10; i++) {
object.get("key" + i);
}
}
}
private static class Writer implements Runnable {
SynchronizedHashMapWithRWLock object;
public Writer(SynchronizedHashMapWithRWLock object) {
this.object = object;
}
@Override
public void run() {
for (int i = 0; i < 10; i++) {
try {
object.put("key" + i, "value" + i);
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/skiplist/Event.java
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package com.baeldung.concurrent.skiplist;
import java.time.ZonedDateTime;
class Event {
private final ZonedDateTime eventTime;
private final String content;
Event(ZonedDateTime eventTime, String content) {
this.eventTime = eventTime;
this.content = content;
}
ZonedDateTime getEventTime() {
return eventTime;
}
String getContent() {
return content;
}
}
core-java-concurrency/src/main/java/com/baeldung/concurrent/skiplist/EventWindowSort.java
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package com.baeldung.concurrent.skiplist;
import java.time.ZonedDateTime;
import java.util.Comparator;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;
class EventWindowSort {
private final ConcurrentSkipListMap<ZonedDateTime, String> events
= new ConcurrentSkipListMap<>(Comparator.comparingLong(value -> value.toInstant().toEpochMilli()));
void acceptEvent(Event event) {
events.put(event.getEventTime(), event.getContent());
}
ConcurrentNavigableMap<ZonedDateTime, String> getEventsFromLastMinute() {
return events.tailMap(ZonedDateTime
.now()
.minusMinutes(1));
}
ConcurrentNavigableMap<ZonedDateTime, String> getEventsOlderThatOneMinute() {
return events.headMap(ZonedDateTime
.now()
.minusMinutes(1));
}
}
core-java-concurrency/src/main/java/com/baeldung/transferqueue/Consumer.java
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package com.baeldung.transferqueue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.TransferQueue;
import java.util.concurrent.atomic.AtomicInteger;
public class Consumer implements Runnable {
private static final Logger LOG = LoggerFactory.getLogger(Consumer.class);
private final TransferQueue<String> transferQueue;
private final String name;
final int numberOfMessagesToConsume;
final AtomicInteger numberOfConsumedMessages = new AtomicInteger();
Consumer(TransferQueue<String> transferQueue, String name, int numberOfMessagesToConsume) {
this.transferQueue = transferQueue;
this.name = name;
this.numberOfMessagesToConsume = numberOfMessagesToConsume;
}
@Override
public void run() {
for (int i = 0; i < numberOfMessagesToConsume; i++) {
try {
LOG.debug("Consumer: " + name + " is waiting to take element...");
String element = transferQueue.take();
longProcessing(element);
LOG.debug("Consumer: " + name + " received element: " + element);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
private void longProcessing(String element) throws InterruptedException {
numberOfConsumedMessages.incrementAndGet();
Thread.sleep(500);
}
}
core-java-concurrency/src/main/java/com/baeldung/transferqueue/Producer.java
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package com.baeldung.transferqueue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TransferQueue;
import java.util.concurrent.atomic.AtomicInteger;
public class Producer implements Runnable {
private static final Logger LOG = LoggerFactory.getLogger(Producer.class);
private final TransferQueue<String> transferQueue;
private final String name;
final Integer numberOfMessagesToProduce;
final AtomicInteger numberOfProducedMessages = new AtomicInteger();
Producer(TransferQueue<String> transferQueue, String name, Integer numberOfMessagesToProduce) {
this.transferQueue = transferQueue;
this.name = name;
this.numberOfMessagesToProduce = numberOfMessagesToProduce;
}
@Override
public void run() {
for (int i = 0; i < numberOfMessagesToProduce; i++) {
try {
LOG.debug("Producer: " + name + " is waiting to transfer...");
boolean added = transferQueue.tryTransfer("A" + i, 4000, TimeUnit.MILLISECONDS);
if (added) {
numberOfProducedMessages.incrementAndGet();
LOG.debug("Producer: " + name + " transferred element: A" + i);
} else {
LOG.debug("can not add an element due to the timeout");
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}