如果队列包含作为参数传递的对象obj,则LinkedBlockingQueue的contains(Object obj)方法将返回true。当且仅当此队列包含至少一个元素e等于等于作为参数传递的对象o即e.equals(o)时,它返回true。此方法对于检查队列中是否包含元素非常有帮助。
用法:
public boolean contains(Object o)
参数:此方法采用强制参数o,该参数是要在队列中检查的对象。
返回值:如果此队列包含作为参数传递的对象,则此方法返回true。否则返回false。
下面的程序说明LinkedBlockingQueue类的contains()方法:
示例1:检查数字队列中是否包含数字n。数字n作为输入传递给LinkedBlockingQueue的contains()。
// Java Program Demonstrate contains(Object o)
// method of LinkedBlockingQueue
import java.util.concurrent.LinkedBlockingQueue;
public class GFG {
public static void main(String[] args)
{
// define capacity of LinkedBlockingQueue
int capacityOfQueue = 50;
// create object of LinkedBlockingQueue
LinkedBlockingQueue<Integer> linkedQueue
= new LinkedBlockingQueue<Integer>(capacityOfQueue);
// Add element to LinkedBlockingQueue
linkedQueue.add(2300);
linkedQueue.add(1322);
linkedQueue.add(8945);
linkedQueue.add(6512);
// print LinkedQueue
System.out.println("linkedQueue: " + linkedQueue);
// check whether LinkedBlockingQueue contains 6512
boolean response1 = linkedQueue.contains(6512);
// print result
System.out.println("LinkedBlockingQueue contains "
+ "number 6512 : "
+ response1);
// check whether LinkedBlockingQueue contains 5324
boolean response2 = linkedQueue.contains(5324);
// print result
System.out.println("LinkedBlockingQueue contains"
+ " number 5324 : "
+ response2);
}
}
输出:
linkedQueue: [2300, 1322, 8945, 6512] LinkedBlockingQueue contains number 6512 : true LinkedBlockingQueue contains number 5324 : false
示例2:检查员工队列中是否包含某些员工e。将雇员e的详细信息作为输入传递给LinkedBlockingQueue的contains()。
// Java Program Demonstrate contains(Object o)
// method of LinkedBlockingQueue.
import java.util.concurrent.LinkedBlockingQueue;
public class GFG {
// create an Employee Object with
// position and salary as an attribute
public class Employee {
public String name;
public String position;
public String salary;
Employee(String name, String position, String salary)
{
this.name = name;
this.position = position;
this.salary = salary;
}
@Override
public String toString()
{
return "Employee [name=" + name + ", position="
+ position + ", salary=" + salary + "]";
}
}
// Main Method
public static void main(String[] args)
{
GFG gfg = new GFG();
gfg.containsMethodExample();
}
public void containsMethodExample()
{
// define capacity of LinkedBlockingQueue
int capacity = 50;
// create object of LinkedBlockingQueue
LinkedBlockingQueue<Employee> linkedQueue
= new LinkedBlockingQueue<Employee>(capacity);
Employee emp1 = new Employee("Aman",
"Analyst",
"24000");
Employee emp2 = new Employee("Sachin",
"Developer",
"39000");
// Add Employee Objects to linkedQueue
linkedQueue.add(emp1);
linkedQueue.add(emp2);
// print LinkedQueue
System.out.println("linkedQueue: " + linkedQueue);
// Employee to be checked
Employee checkEmp1 = new Employee("Sanjeev",
"Tester",
"26000");
// check whether linkedQueue contains emp1
boolean response1 = linkedQueue.contains(emp1);
// print results
System.out.println("linkedQueue contains "
+ emp1.toString() + " : "
+ response1);
// check whether linkedQueue contains checkEmp1
boolean response2 = linkedQueue.contains(checkEmp1);
// print results
System.out.println("linkedQueue contains "
+ checkEmp1.toString() + " : "
+ response2);
}
}
输出:
linkedQueue: [Employee [name=Aman, position=Analyst, salary=24000], Employee [name=Sachin, position=Developer, salary=39000]] linkedQueue contains Employee [name=Aman, position=Analyst, salary=24000] : true linkedQueue contains Employee [name=Sanjeev, position=Tester, salary=26000] : false
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注:本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 LinkedBlockingQueue contains() method in Java。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。