private boolean influencesFragment(ReuseExtensionActivator rexActivator, Fragment fragment) {
   ReuseExtension rex = rexActivator.getReuseExtension();
   if (rex instanceof ComponentModelSpecification) {
     for (EObject root : fragment.getContents()) {
       for (RootElementContext rootElementContext : rex.getRootElementContexts()) {
         if (rootElementContext.getEBoundClass().isInstance(root)) {
           Map<String, String> args = new LinkedHashMap<String, String>();
           for (Argument arg : rexActivator.getArguments()) {
             args.put(arg.getParameter(), arg.getValue());
           }
           if (EvaluatorUtil.eval(
               fragment.getUFI(), root, rootElementContext.getIsExpression(), args)) {
             return true;
           }
         }
       }
     }
   }
   return false;
 }
  private void computeAndCacheCompositionInterface(
      List<String> ufi,
      Resource fragmentResource,
      List<ReuseExtensionActivator> rexActivatorList,
      ResourceSet resourceSet,
      IndexMetaData metaData) {
    Fragment fragment = null;

    // physical or composed?
    List<Constraint> constraints =
        FacetUtil.buildConstraints(
            IndexConstants.COLUMN_COMPOSED_FRAGMENT, ResourceUtil.idString(ufi));
    FacetedRequest request = FacetUtil.buildFacetedRequest(constraints);
    List<IndexRow> response = IndexUtil.INSTANCE.getIndex(request);

    if (response.isEmpty()) {
      fragment = FragmentFactory.eINSTANCE.createPhysicalFragment();
    } else {
      fragment = FragmentFactory.eINSTANCE.createComposedFragment();
    }

    // load
    fragment.getUFI().addAll(ufi);
    fragment.getContents().addAll(fragmentResource.getContents());

    // find reuse extension activators
    for (ReuseExtensionActivator rexActivator : rexActivatorList) {
      if (rexActivator.getReuseExtension() instanceof ComponentModelSpecification) {
        if (influencesFragment(rexActivator, fragment)) {
          fragment.getComponentModelActivators().add(rexActivator);
        }
      }
    }

    // compute composition interface (post processors might need diagrams)
    if (!fragment.getContents().isEmpty()) {
      for (URI fragmentDiagramURI : ReuseResources.INSTANCE.getDiagramURIs(ufi)) {
        Resource fragmentDiagramResource = null;
        try {
          fragmentDiagramResource = resourceSet.getResource(fragmentDiagramURI, true);
        } catch (Exception e) {
          // ok
        }
        if (fragmentDiagramResource != null) {
          fragment.getDiagrams().addAll(fragmentDiagramResource.getContents());
        }
      }
    }
    CompositionInterfaceComputerUtil.compute(fragment);

    // index (cache)
    Resource tempXMIResource = resourceSet.createResource(URI.createURI("temp:/temp.xmi"));
    tempXMIResource.getContents().add(fragment);
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    try {
      tempXMIResource.save(outputStream, resourceSet.getLoadOptions());
      metaData.putSingle(IndexConstants.COLUMN_FRAGMENT, outputStream.toString("UTF-8"));
    } catch (IOException e) {
      e.printStackTrace();
    }
    resourceSet.getResources().remove(tempXMIResource);

    // are there external computers registered?
    // TODO #1656: test this
    DerivedCompositionProgram derivedCp = CompositionProgramExtractorUtil.extract(fragment);
    if (derivedCp != null && derivedCp.getUCPI() != null && !derivedCp.getUCPI().isEmpty()) {
      URI derivedCpURI =
          SokanReuseResourceUtil.getDerivedCompositionProgramURI(
              derivedCp.getUCPI(), fragment.getUFI(), null);
      Resource resource =
          createResourceForDerivedCompositionProgram(derivedCp, derivedCpURI, resourceSet);
      ReuseResourcesUtil.completeCompositionProgram(resource);
    }
  }