LinkedHashMap/LinkedHashSet enhancement: OrderedMap/OrderedSet

[Stuart Marks]

On 4/28/20 9:48 PM, Jason Mehrens wrote:
> Looks like It is intentional that unmodifiable queues are not present.  See: https://bugs.openjdk.java.net/browse/JDK-5030930.  The same logic would have been used for when Deque was added in the following release.

Good find.

Looking at the Queue interface, it adds four mutator methods and two access 
methods: element() and peek(). These latter two provide only a tiny bit of 
convenience over an iterator, so an unmodifiable Queue provides hardly any value 
over Collection. Thus the rationale in JDK-5030930 for not providing an 
unmodifiable Queue makes sense.

Deque is considerably richer than Queue, not only in mutator methods. It also 
adds access methods for both ends (null-returning and throwing), with better 
names, plus a descending iterator. That might make it worthwhile reconsidering 
an unmodifiable Deque.

s'marks