MavenResourcesExecution How to Get as Variable Instead of Writing to A File?

I use that at my plugin:

MavenResourcesExecution mavenResourcesExecution = new MavenResourcesExecution(resources, outputFileDirectory, project, encoding, buildFilters, Collections.<String>emptyList(), session);

    try {
        mavenResourcesFiltering.filterResources(mavenResourcesExecution);
    } catch (MavenFilteringException e) {
        e.printStackTrace();
    }

and it writes everyting into a file however I want to retrieve it as a variable instead of writing it into a file. How can I do it?

I have implemented an interpolator with an interceptor and could retrieve the values of variables.