ArrayBlockingQueue 대 Google Guava 비차단 EvictingQueue 예

게시 됨: 2020-12-29
ArrayBlockingQueue 대 Google Guava 비차단 EvictingQueue 예

동시성 유틸리티는 Java에서 매우 놀랍습니다.

java.util.concurrent 패키지에는 다양한 방법으로 사용할 수 있는 많은 유틸리티가 포함되어 있습니다.

이 튜토리얼에서는 java.util.concurrent의 차이점을 살펴보겠습니다. ArrayBlockingQueue 및 com.google.common.collect. EvictingQueue .

EvictingQueue란 무엇입니까?

EvictingQueue 는 Google's Guava library 일부입니다. 이것은 full queue 에 요소를 추가하려고 할 때 대기열의 head 에서 요소를 자동으로 removes 하는 non-blocking , bounded (고정 크기) 대기열입니다.

eclipse-java 프로젝트에 Google의 Guava 라이브러리를 추가하는 방법은 무엇입니까?

maven 프로젝트를 사용하는 경우 pom.xml 파일에 아래 maven 종속성을 추가할 수 있습니다. non-maven 프로젝트의 경우 – 여기에서 다운로드하고 프로젝트의 클래스 경로에 라이브러리를 포함해야 합니다.

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< dependency >
     < groupId > com . google . guava < / groupId >
     < artifactId > guava < / artifactId >
     < version > 30.1.1 - jre < / version >
< / dependency >

ArrayBlockingQueue란 무엇입니까?

배열에 내부적으로 요소를 저장하는 blocking 되고 bounded (고정 크기) 대기열입니다. 요소를 unlimited 으로 저장할 CAN'T . 이 대기열은 FIFO (선입선출) 요소를 주문합니다.

Read more : 싱글톤 큐 예

예제를 시작하겠습니다.

  1. 크기가 10인 ArrayBlockingQueue 생성
  2. 크기가 10인 EvictingQueue 생성
  3. 대기열에 15개 요소 추가 시도
  4. EvictingQueue의 경우 – 오류가 발생하지 않습니다.
  5. ArrayBlockingQueue의 경우 - Queue Full 오류가 발생합니다.

CrunchifyArrayBlockingQueueVsEvictingQueue.java 클래스 생성

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package crunchify . com . tutorials ;
 
import com . google . common . collect . EvictingQueue ;
 
import java . util . Queue ;
import java . util . concurrent . ArrayBlockingQueue ;
 
/**
* @author Crunchify.com
* ArrayBlockingQueue Vs. Google Guava Non-Blocking EvictingQueue Example
*
*/
 
public class CrunchifyArrayBlockingQueueVsEvictingQueue {
 
private static void CrunchifyArrayBlockingQueue ( ) {
// ArrayBlockingQueue: A bounded blocking queue backed by an array. This queue orders elements FIFO (first-in-first-out).
// The head of the queue is that element that has been on the queue the longest time.
// The tail of the queue is that element that has been on the queue the shortest time.
// New elements are inserted at the tail of the queue, and the queue retrieval operations obtain elements at the head of the queue.
ArrayBlockingQueue < String > crunchifyQueue = new ArrayBlockingQueue < String > (
10 ) ;
 
String crunchifyMsg = "This is ArrayBlockingQueue - by Crunchify" ;
try {
// We are looping for 15 times - Error once queue full
for ( int counter = 1 ; counter < = 15 ; counter ++ ) {
// add(): Inserts the specified element at the tail of this queue if it is possible to do so immediately without exceeding the queue's capacity,
// returning true upon success and throwing an IllegalStateException if this queue is full.
crunchifyQueue . add ( crunchifyMsg + counter ) ;
// size(): Returns the number of elements in this queue.
crunchifyLog ( "ArrayBlockingQueue size: " + crunchifyQueue . size ( ) ) ;
}
} catch ( Exception e ) {
crunchifyLog ( "\nException Occurred: " ) ;
e . printStackTrace ( ) ;
}
 
}
 
public static void main ( String [ ] args ) {
 
// Test EvictingQueue with size 10
CrunchifyEvictingQueue ( ) ;
 
crunchifyLog ( "\n============= New LINE ==============\n" ) ;
 
// Test ArrayBlockingQueue with size 10
CrunchifyArrayBlockingQueue ( ) ;
}
 
private static void CrunchifyEvictingQueue ( ) {
// Queue: A collection designed for holding elements prior to processing. Besides basic Collection operations,
// queues provide additional insertion, extraction, and inspection operations.
// Each of these methods exists in two forms: one throws an exception if the operation fails,
// the other returns a special value (either null or false, depending on the operation).
Queue < String > crunchifyQueue = EvictingQueue . create ( 10 ) ;
 
String crunchifyMsg = "This is EvictingQueue - by Crunchify" ;
try {
// We are looping for 15 times - No error after queue full.
// Instead, it will remove element from queue in FIFO order
for ( int i = 1 ; i < = 15 ; i ++ ) {
// add: Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions,
// returning true upon success and throwing an IllegalStateException if no space is currently available.
crunchifyQueue . add ( crunchifyMsg + i ) ;
 
crunchifyLog ( "EvictingQueue size: " + crunchifyQueue . size ( ) ) ;
}
} catch ( Exception e ) {
crunchifyLog ( "Exception Occurred: " + e ) ;
}
 
}
 
private static void crunchifyLog ( String crunchifyText ) {
System . out . println ( crunchifyText ) ;
 
}
 
}
 

이 Java 프로그램을 Eclipse 콘솔 또는 IntelliJ IDEA에서 애플리케이션으로 실행하기만 하면 다음과 같은 결과가 표시됩니다.

콘솔 결과:

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EvictingQueue size : 1
EvictingQueue size : 2
EvictingQueue size : 3
EvictingQueue size : 4
EvictingQueue size : 5
EvictingQueue size : 6
EvictingQueue size : 7
EvictingQueue size : 8
EvictingQueue size : 9
EvictingQueue size : 10
EvictingQueue size : 10
EvictingQueue size : 10
EvictingQueue size : 10
EvictingQueue size : 10
EvictingQueue size : 10
 
============= New LINE ==============
 
ArrayBlockingQueue size : 1
ArrayBlockingQueue size : 2
ArrayBlockingQueue size : 3
ArrayBlockingQueue size : 4
ArrayBlockingQueue size : 5
ArrayBlockingQueue size : 6
ArrayBlockingQueue size : 7
ArrayBlockingQueue size : 8
ArrayBlockingQueue size : 9
ArrayBlockingQueue size : 10
 
Exception Occurred :
java . lang . IllegalStateException : Queue full
at java . base / java . util . AbstractQueue . add ( AbstractQueue . java : 98 )
at java . base / java . util . concurrent . ArrayBlockingQueue . add ( ArrayBlockingQueue . java : 329 )
at crunchify . com . tutorials . CrunchifyArrayBlockingQueueVsEvictingQueue . CrunchifyArrayBlockingQueue ( CrunchifyArrayBlockingQueueVsEvictingQueue . java : 32 )
at crunchify . com . tutorials . CrunchifyArrayBlockingQueueVsEvictingQueue . main ( CrunchifyArrayBlockingQueueVsEvictingQueue . java : 52 )
 
Process finished with exit code 0

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