This implementation returns true if offer succeeds, else throws an IllegalStateException.
Returns: true (as specified by {@link Collection#add})
Parameters:
- e - the element to add
Throws:
- IllegalStateException - if the element cannot be added at this time due to capacity restrictions
- 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

This implementation iterates over the specified collection, and adds each element returned by the iterator to this queue, in turn. A runtime exception encountered while trying to add an element (including, in particular, a null element) may result in only some of the elements having been successfully added when the associated exception is thrown.
Returns: true if this queue changed as a result of the call
Parameters:
- c - collection containing elements to be added to this queue
Throws:
- ClassCastException - if the class of an element of the specified collection prevents it from being added to this queue
- NullPointerException - if the specified collection contains a null element and this queue does not permit null elements, or if the specified collection is null
- IllegalArgumentException - if some property of an element of the specified collection prevents it from being added to this queue, or if the specified collection is this queue
- IllegalStateException - if not all the elements can be added at this time due to insertion restrictions
See Also: AbstractQueue.add(Object),

This implementation iterates over the elements in the collection, checking each element in turn for equality with the specified element.
Throws:
- ClassCastException - {@inheritDoc}
- NullPointerException - {@inheritDoc}

This implementation iterates over the specified collection, checking each element returned by the iterator in turn to see if it's contained in this collection. If all elements are so contained true is returned, otherwise false.
Throws:
- ClassCastException - {@inheritDoc}
- NullPointerException - {@inheritDoc}
See Also: AbstractCollection.contains(Object),

This implementation returns the result of peek unless the queue is empty.
Returns: the head of this queue
Throws:
- NoSuchElementException - if this queue is empty

This implementation returns size() == 0.

This implementation returns the result of poll unless the queue is empty.
Returns: the head of this queue
Throws:
- NoSuchElementException - if this queue is empty

This implementation iterates over this collection, checking each element returned by the iterator in turn to see if it's contained in the specified collection. If it's so contained, it's removed from this collection with the iterator's remove method.

Note that this implementation will throw an UnsupportedOperationException if the iterator returned by the iterator method does not implement the remove method and this collection contains one or more elements in common with the specified collection.
Throws:
- UnsupportedOperationException - {@inheritDoc}
- ClassCastException - {@inheritDoc}
- NullPointerException - {@inheritDoc}
See Also: AbstractCollection.remove(Object), AbstractCollection.contains(Object),

This implementation iterates over this collection, checking each element returned by the iterator in turn to see if it's contained in the specified collection. If it's not so contained, it's removed from this collection with the iterator's remove method.

Note that this implementation will throw an UnsupportedOperationException if the iterator returned by the iterator method does not implement the remove method and this collection contains one or more elements not present in the specified collection.
Throws:
- UnsupportedOperationException - {@inheritDoc}
- ClassCastException - {@inheritDoc}
- NullPointerException - {@inheritDoc}
See Also: AbstractCollection.remove(Object), AbstractCollection.contains(Object),