The CAS could have a convenience method to fetch a zero-length instance, like e.g. Collections.emptyList() which could return a shared instance. Users caring to optimize could use that without having to implement their own code for managing a shared instance. Users relying on object identity could just manually create an instance.
WDYT? -- Richard > On 14.09.2017, at 16:36, Marshall Schor <m...@schor.com> wrote: > > I was mistaken about Java in one detail: for things like Integer(17), there > are > two ways to create it: new Integer(17), or Integer.valueOf(17). The first > call > does create a fresh, not == to any other Integer object, while the 2nd call > will > reuse an existing Integer object for 17 (if it exists). Users are encouraged > to > switch to Integer.valueOf(xxx) for efficiency in the Javadocs. > > I'm now slightly leaning against doing this change for UIMA, because of the > edge > cases where the user could have depended on object un-equality for 0-length > arrays and lists. > > Users could "manually" achieve the same result using the shared instance > values, > and (for xmi serialization) marking any features that contain these values as > "multi-references-allowed" so the deserialization would share them. This > could > become a suggested "best practice" for those who use 0-length arrays and empty > lists. > > Not doing this would make two Jiras a "won't fix": > https://issues.apache.org/jira/browse/UIMA-5564 > https://issues.apache.org/jira/browse/UIMA-5566 > > What do others think? > > -Marshall
