UnsupportedOperationException

[[e-mail] [seajug]]

I was surprised this doesn't work.


List<String> argh = Arrays.asList( "ABC","XYZ" );

argh.clear();


Then I had to read the javadoc. Saays "proxy for original list", not "the result is immutable".


Further, an immutable list shouldn't have a clear() method.

[Dennis Sosnoski dms-WAiJhE/vqclWk0Htik3J/[e-mail] [seajug]]

One of the many questionable design decisions for the Java collections
classes. It would have made more sense to have an basic List interface
that just defined the non-mutating methods, then a MutableList interface
that extended List. And I would have added separate RandomAccessList and
MutableRandomAccessList interfaces which guarantee constant time access
to items in the list (vs. linked lists with O(n) access time).

- Dennis

Post by zappini-***@public.gmane.org [seajug]
I was surprised this doesn't work.
List<String> argh = Arrays.asList( "ABC","XYZ" );
argh.clear();
Then I had to read the javadoc. Saays "proxy for original list", not
"the result is immutable".
Further, an immutable list shouldn't have a clear() method.

[George Smith [e-mail] [seajug]]

I completely concur w/ Dennis.

Since the GOF (Gang Of Four) "Design Patterns" book was published in 94/95,
and the Java Collections were released in December of 98, it has been a
major frustration of mine that the the Java Collections did not implement
the GOF Iterator!

The GOF Iterator, with the following methods:

- First()
- Next()
- IsDone()
- CurrentItem()

provides the following things that the Java Iterator doesn't:

1. reusable (can traverse the backing collection as many times as you
need),
2. a Read-Only View,
3. repeated access to the Current Item (w/o needing a local variable).

These features, in combination, meant that except for Random Access, a GOF
Iterator WAS a reasonable accessor return type for read-only access to an
underlying collection.

George

Post by Dennis Sosnoski dms-WAiJhE/vqclWk0Htik3J/***@public.gmane.org [seajug]
One of the many questionable design decisions for the Java collections
classes. It would have made more sense to have an basic List interface that
just defined the non-mutating methods, then a MutableList interface that
extended List. And I would have added separate RandomAccessList and
MutableRandomAccessList interfaces which guarantee constant time access to
items in the list (vs. linked lists with O(n) access time).
- Dennis
I was surprised this doesn't work.
List<String> argh = Arrays.asList( "ABC","XYZ" );
argh.clear();
Then I had to read the javadoc. Saays "proxy for original list", not
"the result is immutable".
Further, an immutable list shouldn't have a clear() method.