Commit4022255

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Add Semaphore example

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+54

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src/com/winterbe/java8/samples/concurrent
- Semaphore1.java
- Synchronized1.java

+54

-2

lines changed

Lines changed: 51 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,51 @@`
	`1`	`+packagecom.winterbe.java8.samples.concurrent;`
	`2`	`+`
	`3`	`+importjava.util.concurrent.ExecutorService;`
	`4`	`+importjava.util.concurrent.Executors;`
	`5`	`+importjava.util.concurrent.Semaphore;`
	`6`	`+importjava.util.concurrent.TimeUnit;`
	`7`	`+importjava.util.stream.IntStream;`
	`8`	`+`
	`9`	`+/**`
	`10`	`+ * @author Benjamin Winterberg`
	`11`	`+ */`
	`12`	`+publicclassSemaphore1 {`
	`13`	`+`
	`14`	`+privatestaticfinalintNUM_INCREMENTS =10000;`
	`15`	`+`
	`16`	`+privatestaticSemaphoresemaphore =newSemaphore(1);`
	`17`	`+`
	`18`	`+privatestaticintcount =0;`
	`19`	`+`
	`20`	`+publicstaticvoidmain(String[]args) {`
	`21`	`+testIncrement();`
	`22`	`+ }`
	`23`	`+`
	`24`	`+privatestaticvoidtestIncrement() {`
	`25`	`+ExecutorServiceexecutor =Executors.newFixedThreadPool(2);`
	`26`	`+`
	`27`	`+IntStream.range(0,NUM_INCREMENTS)`
	`28`	`+ .forEach(i ->executor.submit(Semaphore1::increment));`
	`29`	`+`
	`30`	`+ConcurrentUtils.stop(executor);`
	`31`	`+`
	`32`	`+System.out.println("Increment: " +count);`
	`33`	`+ }`
	`34`	`+`
	`35`	`+privatestaticvoidincrement() {`
	`36`	`+booleanpermit =false;`
	`37`	`+try {`
	`38`	`+permit =semaphore.tryAcquire(5,TimeUnit.SECONDS);`
	`39`	`+count++;`
	`40`	`+ }`
	`41`	`+catch (InterruptedExceptione) {`
	`42`	`+thrownewRuntimeException("could not increment");`
	`43`	`+ }`
	`44`	`+finally {`
	`45`	`+if (permit) {`
	`46`	`+semaphore.release();`
	`47`	`+ }`
	`48`	`+ }`
	`49`	`+ }`
	`50`	`+`
	`51`	`+}`

Lines changed: 3 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -19,7 +19,7 @@ public static void main(String[] args) {`
`19`	`19`	`}`
`20`	`20`
`21`	`21`	`privatestaticvoidtestSyncIncrement() {`
`22`		`-count =1;`
	`22`	`+count =0;`
`23`	`23`
`24`	`24`	`ExecutorServiceexecutor =Executors.newFixedThreadPool(2);`
`25`	`25`
`@@ -32,7 +32,7 @@ private static void testSyncIncrement() {`
`32`	`32`	`}`
`33`	`33`
`34`	`34`	`privatestaticvoidtestNonSyncIncrement() {`
`35`		`-count =1;`
	`35`	`+count =0;`
`36`	`36`
`37`	`37`	`ExecutorServiceexecutor =Executors.newFixedThreadPool(2);`
`38`	`38`
`@@ -51,4 +51,5 @@ private static synchronized void incrementSync() {`
`51`	`51`	`privatestaticvoidincrement() {`
`52`	`52`	`count =count +1;`
`53`	`53`	`}`
	`54`	`+`
`54`	`55`	`}`

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