关于java中的队列几个重要函数

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http://docs.oracle.com/javase/7/docs/api/java/util/Queue.html#offer(E)

offer   来自Queue类

boolean offer(E e)

Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions. When using a capacity-restricted queue, this method is generally preferable to add(E), which can fail to insert an element only by throwing an exception.

Parameters:

e - the element to add

Returns:

true if the element was added to this queue, else false

Throws:

ClassCastException - if the class of the specified element prevents it from being added to this queue

NullPointerException - if the specified element is null and this queue does not permit null elements

IllegalArgumentException - if some property of this element prevents it from being added to this queue

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LinkedList类中的offer方法

public boolean offer(E e)

Adds the specified element as the tail (last element) of this list.

Specified by:

offer in interface Deque<E>

Specified by:

offer in interface Queue<E>

Parameters:

e - the element to add

Returns:

true (as specified by Queue.offer(E))

Since:

1.5

add方法  注意参数e是否可以是null

public boolean add(E e)

Appends the specified element to the end of this list.

This method is equivalent to addLast(E). 

 

public E peek()

Retrieves, but does not remove, the head (first element) of this list.

poll

public E poll()

Retrieves and removes the head (first element) of this list.

转载于:https://my.oschina.net/ray1421/blog/790356