Java中BlockingDeque offerLast()方法及其示例

BlockingDeque 中的 offerLast(E e) 方法将传入参数的元素插入到Deque容器的末端。如果容器的容量已经超过，则不像add()和addLast()函数一样返回异常。

语法：

public boolean offerLast(E e)

参数：

此方法接受一个 e 参数，该参数是要插入到BlockingDeque末尾的元素。

返回值：

如果已插入元素，则返回true，否则返回false。

注： BlockingDeque 中的offerLast()方法是从Java中的LinkedBlockingDeque类继承而来。

以下程序说明了BlockingDeque的offerLast()方法：

程序1：

// Java Program Demonstrate offerLast()
// 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 IllegalStateException
    {
  
        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>(4);
  
        // Add numbers to end of BlockingDeque
        BD.offerLast(7855642);
        BD.offerLast(35658786);
        BD.offerLast(5278367);
        BD.offerLast(74381793);
  
        // Cannot be inserted
        BD.offerLast(10);
  
        // cannot be inserted hence returns false
        if (!BD.offerLast(10))
            System.out.println("The element 10 cannot be inserted"
                               + " as capacity is full");
  
        // before removing print queue
        System.out.println("Blocking Deque: " + BD);
    }
}

结果：元素10无法插入，因为容量已满
Blocking Deque: [7855642, 35658786, 5278367, 74381793]```  

程序2：

// Java Program Demonstrate offerLast()
// 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 IllegalStateException
    {
  
        // create object of BlockingDeque
        BlockingDeque<String> BD
            = new LinkedBlockingDeque<String>(4);
  
        // Add numbers to end of BlockingDeque
        BD.offerLast("abc");
        BD.offerLast("gopu");
        BD.offerLast("geeks");
        BD.offerLast("richik");
  
        // Cannot be inserted
        BD.offerLast("hii");
  
        // cannot be inserted hence returns false
        if (!BD.offerLast("hii"))
            System.out.println("The element 'hii' cannot be"
                               + " inserted as capacity is full");
  
        // before removing print queue
        System.out.println("Blocking Deque: " + BD);
    }
}

结果：元素'hii'无法插入，因为容量已满
Blocking Deque: [abc, gopu, geeks, richik]```  

参考文献： https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#offerLast(E)