SetQueue (RabbitMQ Java Client 4.12.0 API)

java.lang.Object
- com.rabbitmq.client.impl.SetQueue<T>

Type Parameters:

T - type of elements in the queue
```
public class SetQueue<T>
extends Object
```
A generic queue-like implementation (supporting operations addIfNotPresent, poll, contains, and isEmpty) which restricts a queue element to appear at most once. If the element is already present addIfNotPresent(T) returns false.
Elements must not be null.
Concurrent Semantics
This implementation is not thread-safe.

Constructor Summary

Constructors
Constructor Description

SetQueue()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`addIfNotPresent(T item)`	Add an element to the back of the queue and return `true`, or else return `false`.
`void`	`clear()`	Remove all items from the queue.
`boolean`	`contains(T item)`
`boolean`	`isEmpty()`
`T`	`poll()`	Remove the head of the queue and return it.
`boolean`	`remove(T item)`	Remove item from queue, if present.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SetQueue
```
public SetQueue()
```
- Method Detail
  - addIfNotPresent
```
public boolean addIfNotPresent(T item)
```
    Add an element to the back of the queue and return true, or else return false.
    
    Parameters:
    
    item - to add
    
    Returns:
    
    true if the element was added, false if it is already present.
  - poll
```
public T poll()
```
    Remove the head of the queue and return it.
    
    Returns:
    
    head element of the queue, or null if the queue is empty.
  - contains
```
public boolean contains(T item)
```
    Parameters:
    
    item - to look for in queue
    
    Returns:
    
    true if and only if item is in the queue.
  - isEmpty
```
public boolean isEmpty()
```
    Returns:
    
    true if and only if the queue is empty.
  - remove
```
public boolean remove(T item)
```
    Remove item from queue, if present.
    
    Parameters:
    
    item - to remove
    
    Returns:
    
    true if and only if item was initially present and was removed.
  - clear
```
public void clear()
```
    Remove all items from the queue.