OSGi does provide a mechanism to have the import-package include
specifying which bundle it should come from. See section 3.6.8
"Provider Selection" in the r4.core.pdf doc for OSGi for details.
The POMs we use don't generate this though. Do you see that allowing
multiple bundles to export the same package name, and then having our
configuration be more explicit about which bundle to wire to, is (or may
be) a design requirement?
-Marshall
Tong Fin wrote:
Hi,
The current UIMA Eclipse plugins (runtime, CDE, etc.) use "Imported
Packages" for declaring dependencies instead of "Required Plug-ins". This
declaration is automatically generated by Maven (I think ?) and gives more
fine grained controls on what to depend on.
But, there are some side-effects from this approach which may cause the
problems. The imported packages may wired to the correct packages from the
"wrong" plugins.
Today, while I am testing the new UIMA build candidate 03 with my plugins, I
had this "wrong" wiring situation. The following is what happen:
- One of my plugins has two exported packages named "org.apache.uima.util"
and "org.apache.uima.jcas.tcas" which are the same as the packages exported
by "org.apache.uima.runtime".
- UIMA runtime plugin (org.apache.uima.runtime) exports "
org.apache.uima.util" and "org.apache.uima.jcas.tcas" packages and it also
imports these two packages.
- UIMA CDE plugin uses some classes (e.g., XMLizable) from "
org.apache.uima.util" which is imported by using "Imported Packages"
approach.
- At runtime, Eclipse OSGi has the following wiring:
id State Bundle
0 ACTIVE org.eclipse.osgi_3.3.1.R33x_v20070828
1 ACTIVE org.eclipse.equinox.common_3.3.0.v20070426
2 ACTIVE org.eclipse.update.configurator_3.2.101.R33x_v20070810
3 ACTIVE org.eclipse.core.runtime_3.3.100.v20070530
4 ACTIVE org.apache.uima.desceditor_2.2.2.incubating
5 <<LAZY>> org.apache.uima.editors.dde_2.2.2.incubating
232 <<LAZY>> org.apache.uima.jcas.jcasgenp_2.2.2.incubating
233 <<LAZY>> org.apache.uima.pear_2.2.2.incubating
234 RESOLVED org.apache.uima.runtime_2.2.2.incubating
Fragments=235
235 RESOLVED
org.apache.uima.runtime.fragments.deployeditor_2.2.2.incubating
Master=234
For CDE (bundle#4), "org.apache.uima.util" package is imported from
Bundle#194
org.apache.uima.util;
version="0.0.0"<[EMAIL
PROTECTED]/ws-test/org.apache.uima.runtimetoolkit.container/
[194]>
For UIMA runtime plugin "org.apache.uima.runtime" (Bundle#234), it has the
following resolution:
org.apache.uima.jcas.tcas;
version="0.0.0"<[EMAIL
PROTECTED]/ws-test/org.apache.uima.runtimetoolkit.container/
[194]>
org.apache.uima.util;
version="0.0.0"<[EMAIL
PROTECTED]/ws-test/org.apache.uima.runtimetoolkit.container/
[194]>
>From the above imported resolution, "org.apache.uima.util" and "
org.apache.uima.jcas.tcas" come from the wrong plugin (Bundle#194) which
cause the problem for CDE to properly run.
It is a good idea to document this so that the tools that use UIMA plugin
will not create the wrong wiring as the above example.
Comment ?
- Tong
