On 7/4/18, 5:41 AM, Nasser Ebrahim wrote:
Hello,
Am starting this mail thread to discuss about adding new IBM extended
charsets. The questions is whether we need to add the new extended
charsets to jdk.charsets or to a new separate charset provider/module like
jdk.ibmcharsets. This discussion is in continuation of the suggestion from
Alan Bateman in the mail chain -
http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-May/053316.html.
Am copying his inputs from that mail thread to start the discussion:
"I think we should start a discussion here about moving some or all of the
IBM charsets to their own service provider module. I realize the AIX port
might want to include some of them in its build of java.base but they
aren't interesting to include in java.base, or even jdk.charsets, on most
platform"
First, let me clarify whether IBM charsets are applicable only to IBM
platforms like AIX or applicable to other platforms as well. All IBM
charsets are applicable to any platforms including Linux and windows if
those platforms needs to communicate with an application or database in
IBM platforms like AIX. That is the reason, we traditionally add them to
the jdk.charsets. However, we agree with Alan that those IBM charsets are
not required if the JDK is not communicating to any applications/databases
on IBM platforms. Hence, it makes sense to consider a separate charset
provider / module for IBM charsets and use build parameters to decide
whether to generate the new charset provider or not for any platforms.
Let me list out all the possible options I can think of for adding new
extended charsets so that we can discuss and decide which is the best
option.
1) Continue to add new extended charsets to jdk.charsets.
The advantage with this approach is that no need to add new charset
provider and all extended charsets are placed in one module. Also, any
extended charset is applicable to any platform if they need to communicate
with application/database in different platforms. The disadvantage is that
the number of charsets in jdk.charsets keep increasing and blot its size.
Also, many of those charsets may not be used in the lifetime of the JDK
unless it is communicating with application/databases of those platforms.
2) Create a new charset provider and module (say jdk.ibmcharsets) for all
IBM charsets and include the new module in JDK on a need basis.
The advantage with this approach is that the foot print of jdk.charsets
can be reduced and can include the new module only if it is required. The
disadvantage is that a new charset provider needs to be created. Also,
extended charsets will be located in two different modules and many a
times both the modules are required.
3) Remove all extended charsets from JDK (keep only default charsets) and
use the extended charsets from third party like ICU4J.
I believe this option might be discussed in the past and there might be
valid reason not to pursue this option. Am still listing it to ensure that
we have considered this option as well. The advantage with this approach
is that we can avoid maintaining the same charsets by two different open
source communities. The disadvantage with this option is that the release
cycle of the two communities may be different and we may need to maintain
the level ourselves for LTS releases as we may not want to change the
specification in a service stream.
Please share your thoughts on your preferred option and list out any other
options which I missed out. Thank you for your time.
Hi Nasser,
I would assume the best option might be (3), in which only keeps those
ibm charsets that might be used/configured to be the default charset for
vm startup on IBM platform, and leaves the rest to icu4j charsets provider.
There are hundreds of IBM specific charsets, and with various versions that
probably are not going to be used by most of the Java developers in most
normal use scenarios. I would assume it's NOT in our best interest to
implement,
test and support/maintain them in openjdk project/repo. Since the jar is
maven repo already, any request for the support of those charsets can be
pointed
to there accordingly. I did not know there is such package/jar in the maven.
I did check the icu4j years ago and there was no nio provider interface
provided
back then.
For those to be kept in openjdk repo, they could/should be separated from
the extended charsets and kept into a separate package/module as well, and
probably are only configured to build into the binaries for IBM
platforms, and
maintained by the AIX port.
Thanks,
Sherman
