code: static DumpWriter addFilter(DumpWriter sink, String filter, String param) throws IOException, ParseException {
  		if (filter.equals("latest"))
  			return new LatestFilter(sink);
  		else if (filter.equals("namespace"))
  			return new NamespaceFilter(sink, param);
  		else if (filter.equals("notalk"))
  			return new NotalkFilter(sink);
  		else if (filter.equals("titlematch"))
  			return new TitleMatchFilter(sink, param);
  		else if (filter.equals("list"))
  			return new ListFilter(sink, param);
  		else if (filter.equals("exactlist"))
  			return new ExactListFilter(sink, param);
  		else if (filter.equals("revlist"))
  			return new RevisionListFilter(sink, param);
  		else if (filter.equals("before"))
  			return new BeforeTimeStampFilter(sink, param);
  		else if (filter.equals("after"))
  			return new AfterTimeStampFilter(sink, param);
  		else
  			throw new IllegalArgumentException("Filter unknown: " + filter);
  	}
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