Java BlockingDeque removeFirstOccurrence()用法及代碼示例

BlockingDeque的removeFirstOccurrence()方法從此雙端隊列中刪除指定元素的首次出現。如果雙端隊列不包含元素，則它將保持不變。如果此雙端隊列包含指定的元素，則返回true，否則返回false。

用法:

public boolean removeFirstOccurrence(Object o)

參數：此方法接受必需的參數o，該參數指定要從Deque容器中刪除的元素。

返回值：如果該元素存在並且已從Deque容器中刪除，則此方法返回true，否則返回false。

注意：BlockingDeque的removeFirstOccurrence()方法已從Java中的LinkedBlockingDeque類繼承。

以下示例程序旨在說明BlockingDeque的removeFirstOccurrence()方法：

示例1:當元素存在時

// Java Program to demonstrate removeFirstOccurrence() 
// method of BlockingDeque 
  
import java.util.concurrent.LinkedBlockingDeque; 
import java.util.concurrent.BlockingDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
        throws InterruptedException 
    { 
  
        // create object of BlockingDeque 
        BlockingDeque<Integer> BD 
            = new LinkedBlockingDeque<Integer>(); 
  
        // Add numbers to end of BlockingDeque 
        BD.add(15); 
        BD.add(20); 
        BD.add(20); 
        BD.add(15); 
  
        // print Deque 
        System.out.println("Blocking Deque: " + BD); 
  
        if (BD.removeFirstOccurrence(15)) 
            System.out.println("Fist occurrence of 15 removed"); 
        else
            System.out.println("15 not present and not removed"); 
  
        // prints the Deque after removal 
        System.out.println("Blocking Deque: " + BD); 
    } 
}

輸出：

Blocking Deque: [15, 20, 20, 15]
Fist occurrence of 15 removed
Blocking Deque: [20, 20, 15]

示例2:當元素不存在時

// Java Program to demonstrate removeFirstOccurrence() 
// method of BlockingDeque 
  
import java.util.concurrent.LinkedBlockingDeque; 
import java.util.concurrent.BlockingDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
        throws InterruptedException 
    { 
  
        // create object of BlockingDeque 
        BlockingDeque<Integer> BD 
            = new LinkedBlockingDeque<Integer>(); 
  
        // Add numbers to end of BlockingDeque 
        BD.add(15); 
        BD.add(20); 
        BD.add(20); 
        BD.add(15); 
  
        // print Deque 
        System.out.println("Blocking Deque: " + BD); 
  
        if (BD.removeFirstOccurrence(10)) 
            System.out.println("Fist occurrence of 10 removed"); 
        else
            System.out.println("10 not present and not removed"); 
  
        // prints the Deque after removal 
        System.out.println("Blocking Deque: " + BD); 
    } 
}

輸出：

Blocking Deque: [15, 20, 20, 15]
10 not present and not removed
Blocking Deque: [15, 20, 20, 15]

參考： https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#removeFirstOccurrence(java.lang.Object)

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注：本文由純淨天空篩選整理自gopaldave大神的英文原創作品 BlockingDeque removeFirstOccurrence() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。