[news.eclipse.platform] Re: Multiple classpath options?

[Jerome Lanneluc <jerome_lanneluc@xxxxxxxxxx>]

Joe Zulli wrote:
> Essentially, I'm looking for a creative way to solve this problem, 
> preferrably while writing as little code as possible. One thought (don't 
> know how feasible this is) is to write some plugin that modifies the 
> schema of the .classpath so that if both a dependent project and a jar 
> are specified (and somehow linked together) the dependent project will 
> be used if and only if it exists in the workspace.

Since 3.2M5a you can specify that a classpath entry is optional using IClasspathAttribute#OPTIONAL.
E.g.
  IClasspathAttribute attribute = JavaCore.newClasspathAttribute(IClasspathAttribute.OPTIONAL, "true");
  IClasspathEntry projectEntry = JavaCore.newProjectEntry(new Path("/P"), null/*no access rules*/, false/*don't combine access rule*/, new IClasspathAttribute[] {attribute}, false/*not exported*/);

Or if you prefer to modify the .classpath file directly:
	<classpathentry kind="src" path="/P">
		<attributes>
			<attribute name="optional" value="true"/>
		</attributes>
	</classpathentry>

However while testing this, I discovered that the Java builder will still complain for optional projects.
This is going to be fixed for next integration build.

Jerome