Java 中的 BlockingDeque addFirst()方法,示例
原文:https://www . geeksforgeeks . org/blocking eque-addfirst-method-in-Java-with-examples/
阻塞请求的 addFirst(E e) 方法将参数中传递的元素插入到有空间的德格前面。如果阻塞请求受到容量限制并且没有空间可供插入,它将返回一个非法状态异常。
语法:
public void addFirst(E e)
参数:该方法接受一个强制参数 e ,它是要插入到阻塞请求前面的元素。
返回:这个方法不返回任何东西。
异常:
- [T0】 illegalstatexception 【T1]: If the element cannot be added due to capacity limitation at this time.
- [T0】 NullPointerException 【T1]: If the specified element is empty.
注:blocking eque的 addFirst()方法是从 Java 中的link edblocking eque类继承而来的。
下面的程序说明了阻塞队列的 addFirst()方法:
程序 1:
// Java Program Demonstrate addFirst()
// 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>();
// Add numbers to front of BlockingDeque
BD.addFirst(7855642);
BD.addFirst(35658786);
BD.addFirst(5278367);
BD.addFirst(74381793);
// before removing print Dequq
System.out.println("Blocking Deque: " + BD);
}
}
输出:
Blocking Deque: [74381793, 5278367, 35658786, 7855642]
节目 2:
// Java Program Demonstrate addFirst()
// method of BlockingDeque
// when it is Full
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
// size of list
BlockingDeque<Integer> BD
= new LinkedBlockingDeque<Integer>(3);
// Add numbers to front of BlockingDeque
BD.addFirst(7855642);
BD.addFirst(35658786);
BD.addFirst(5278367);
// it is full
BD.addFirst(74381793);
// before removing print Deque
System.out.println("Blocking Deque: " + BD);
}
}
输出:
Exception in thread "main" java.lang.IllegalStateException: Deque full
at java.util.concurrent.LinkedBlockingDeque.addFirst(LinkedBlockingDeque.java:326)
at GFG.main(GFG.java:24)
节目 3:
// Java Program Demonstrate addFirst()
// method of BlockingDeque
// when nill is inserted
import java.util.concurrent.BlockingDeque;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
public class GFG {
public static void main(String[] args)
throws IllegalStateException
{
// create object of BlockingDeque
BlockingDeque<Integer> BD
= new LinkedBlockingDeque<Integer>();
// Add numbers to front of BlockingDeque
BD.addFirst(7855642);
BD.addFirst(35658786);
BD.addFirst(5278367);
// NULL
BD.addFirst(null);
// before removing print Deque
System.out.println("Blocking Deque: " + BD);
}
}
输出:
Exception in thread "main" java.lang.NullPointerException
at java.util.concurrent.LinkedBlockingDeque.offerFirst(LinkedBlockingDeque.java:342)
at java.util.concurrent.LinkedBlockingDeque.addFirst(LinkedBlockingDeque.java:325)
at GFG.main(GFG.java:24)
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