wro4j-core/src/main/java/ro/isdc/wro/model/group/processor/PreProcessorExecutor.java
public String processAndMerge(final List<Resource> resources, final boolean minimize)
      throws IOException {
    return processAndMerge(resources, ProcessingCriteria.create(ProcessingType.ALL, minimize));
  }
public String processAndMerge(final List<Resource> resources, final boolean minimize)
      throws IOException {
    return processAndMerge(resources, ProcessingCriteria.create(ProcessingType.ALL, minimize));
  }
Apply preProcessors on resources and merge them after all preProcessors are applied.

@param resources
what are the resources to merge.
@param minimize
whether minimize aware processors must be applied or not.
@return preProcessed merged content.