Condition
Wait /notify/notifyAll
Condition has a similar function, but may have more features such as: no response to interrupt, can specify the end of the wait, can have multiple conditions (new multiple conditions).
Condition await is similar to wait until the lock is acquired
A, use,
/ * * *@authorDay and night of wood */
public class ConditionTest {
public static Lock lock = new ReentrantLock();
//
public static Condition cd01 = lock.newCondition();
public static void main(String[] args) throws InterruptedException {
ConditionTest test = new ConditionTest();
new Thread(test::say01).start();
Thread.sleep(5000);
new Thread(test::say02).start();
}
/** * says: I'm hungry */
public void say01(a){
try{
lock.lock();
System.out.println("I'm hungry.");
cd01.await();
System.out.println("Full");
} catch (Exception e){
e.printStackTrace();
} finally{ lock.unlock(); }}/** * says: Dinner is ready */
public void say02(a){
try{
lock.lock();
cd01.signal();
System.out.println("Dinner is served.");
} catch (Exception e){
e.printStackTrace();
} finally{ lock.unlock(); }}} I am hungry and fullCopy the codeTwo, do not respond to interrupt
Look at say01 say02 interruptible Say03 uninterruptible
public class ConditionTest02 {
public static Object obj = new Object();
public static Lock lock = new ReentrantLock();
public static Condition cd01 = lock.newCondition();
public static void main(String[] args) throws InterruptedException {
ConditionTest02 test = new ConditionTest02();
Thread thread = new Thread(test::say01);
Thread thread02 = new Thread(test::say02);
Thread thread03 = new Thread(test::say03);
thread.start();
thread02.start();
thread03.start();
Starve them for 5 seconds
Thread.sleep(5000);
/ / the interrupt
thread.interrupt();
thread02.interrupt();
Say03 will interrupt and fail
thread03.interrupt();
}
/** * says: Jack is hungry */
public void say01(a){
try{
lock.lock();
System.out.println("Jack is hungry.");
System.out.println("Cockroaches waiting to feed.");
cd01.await();
System.out.println("Jack Bauer is full.");
}catch (InterruptedException e){
System.out.println("Cockroaches are out looking for food.");
}catch (Exception e){
e.printStackTrace();
} finally{ lock.unlock(); }}/** * says: Xiao Ming is hungry */
public void say02(a){
try{
synchronized (obj){
System.out.println("Xiao Ming is hungry.");
System.out.println("Xiao Ming waits for feeding.");
obj.wait();
System.out.println("Xiao Ming is full."); }}catch (InterruptedException e){
System.out.println("Xiao Ming is out looking for food."); }}/** * says: moonbird hungry interrupt useless */
public void say03(a){
try{
lock.lock();
System.out.println("Moonbird is hungry.");
System.out.println("Moonbirds waiting to feed.");
cd01.awaitUninterruptibly();
System.out.println("Moonbird is full.");
}catch (Exception e){
System.out.println("Moonbirds are out looking for food.");
e.printStackTrace();
} finally{ lock.unlock(); }}} Output result: Ming is hungry, Ming is waiting for feeding, And Xiaoqiang is hungry. Xiaoqiang is hungry, and Xiaoqiang is waiting for feedingCopy the codeWait a minute
Condition can await await for a while until he realizes that no one is listening to him and then stops awaiting await
An Object wait can also specify a timeout
public class ConditionTest03 {
public static Lock lock = new ReentrantLock();
//
public static Condition cd01 = lock.newCondition();
public static void main(String[] args) {
ConditionTest03 test = new ConditionTest03();
new Thread(test::say01).start();
}
/** * says: I'm hungry */
public void say01(a){
try{
lock.lock();
System.out.println("I'm hungry.");
System.out.println("Waiting to be fed");
//
// The unit needed for this is millisecond *1000*1000000 which is 5000000000L millisecond = 5 seconds
// Nanos is equal to 5000000000L
long nanos = TimeUnit.SECONDS.toNanos(5);
long res = cd01.awaitNanos(5000000000L);
// It can also return true false
// boolean res = cd01.await(10,TimeUnit.SECONDS);
/ / timeout
if (res <= 0){
System.out.println("No one will feed me.");
} else {
System.out.println("I've been fed enough."); }}catch (Exception e){
e.printStackTrace();
} finally{ lock.unlock(); }}}Copy the code4. Designate time
A wait can be specified to end at a specified point in time
public class LockTest04 {
/ / a new lock
public static Lock lock = new ReentrantLock(false);
public static Condition cd = lock.newCondition();
public static void main(String[] args) throws InterruptedException {
new Thread(()->{
try {
lock.lock();
long l = System.currentTimeMillis();
l = l +1000*10;
Date date = new Date(l);
boolean res = cd.awaitUntil(date);
if(res) {
System.out.println("Be informed");
} else {
System.out.println("I left without notice."); }}catch (Exception e){
e.printStackTrace();
}finally{ lock.unlock(); } }).start(); }}Copy the codeCreate multiple conditions
Here is an example: Xiaoqiang and Xiaoyueyue two people playing toys xiaoqiang play not to play to Xiaoyueyue xiaoyueyue play not to play to Xiaoqiang
public class PlayTest {
public static Lock lock = new ReentrantLock();
public static Condition cd01 = lock.newCondition();
public static void main(String[] args) {
PlayTest test = new PlayTest();
new Thread(test::xiaoqiangPlay).start();
new Thread(test::xiaoxuexuePlay).start();
}
// Jack Bauer
public void xiaoqiangPlay(a){
try {
while (true){
lock.lock();
System.out.println(Jack Bauer);
Thread.sleep(5000);
// Tell someone to play
cd01.signal();
// Wait to be informedcd01.await(); }}catch (Exception e) {
e.printStackTrace();
} finally{ lock.unlock(); }}// Play next month
public void xiaoxuexuePlay(a){
try {
while(true){
lock.lock();
System.out.println("Little Yueyue play");
Thread.sleep(5000);
// Tell someone to play
cd01.signal();
// Wait to be informedcd01.await(); }}catch (Exception e) {
e.printStackTrace();
} finally{ lock.unlock(); }}}Copy the codeYou can use two conditions
public class PlayTest02 {
public static Lock lock = new ReentrantLock();
public static Condition cd01 = lock.newCondition();
public static Condition cd02 = lock.newCondition();
public static void main(String[] args) {
PlayTest02 test = new PlayTest02();
new Thread(test::xiaoqiangPlay).start();
new Thread(test::xiaoxuexuePlay).start();
}
// Jack Bauer
public void xiaoqiangPlay(a){
try {
while (true){
lock.lock();
System.out.println(Jack Bauer);
Thread.sleep(5000);
// Tell someone to play
cd01.signal();
// Wait to be informedcd02.await(); }}catch (Exception e) {
e.printStackTrace();
} finally{ lock.unlock(); }}// Play next month
public void xiaoxuexuePlay(a){
try {
while(true){
lock.lock();
System.out.println("Little Yueyue play");
Thread.sleep(5000);
// Tell someone to play
cd02.signal();
// Wait to be informedcd01.await(); }}catch (Exception e) {
e.printStackTrace();
} finally{ lock.unlock(); }}}Copy the codeTwo conditions do not interfere with each other, and you can specify condition await/signal
Condition signalAll and notifyAll are similar and are not demonstrated in code
Six, summarized
- Create Condition (multiple conditions can be created without affecting each other)
- Can only be used after lock has acquired the lock
- Await supports interrupt without corresponding, timeout (Object wait also supports), end at a specified point in time
- Signal wakes up one thread. SignalAll wakes up all threads
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