public static void printViewPatterns() {
      processedViewsForPatterns = new HashSet<ViewTrace>();
      HashMap<String, Integer> viewPatterns = new HashMap<String, Integer>();

      ps.println("ViewPatterns ------------------- \n");
      for (ViewTrace trace : viewsRegistry) {
        if (processedViewsForPatterns.contains(trace)) {
          continue;
        }
        ViewTrace v = trace.getRootView();
        StringBuilder p = new StringBuilder();
        p.append("PATTERN ");
        extractViewPattern(0, v, p);
        p.append("\n");
        String pattern = p.toString();
        Integer count = viewPatterns.get(pattern);
        if (count == null) {
          viewPatterns.put(pattern, 1);
        } else {
          viewPatterns.put(pattern, count + 1);
        }
      }
      processedViewsForPatterns = null;
      for (Map.Entry<String, Integer> e : viewPatterns.entrySet()) {
        ps.print("(" + e.getValue() + ") ");
        ps.println(e.getKey());
      }
    }
    public static void printSite(Site s, StringBuilder out) {
      if (s == null) {
        out.append("(null)");
        return;
      }
      StackTraceElement[] st = s.site();

      int interestingSitesPrinted = 0;
      for (int i = s.offset; i < st.length; i++) {
        StackTraceElement e = st[i];
        String fileName = e.getFileName();
        if (THIS_FILE_NAME.equals(fileName)) {
          continue;
        }
        out.append(" " + e.getMethodName() + "(" + e.getFileName() + ":" + e.getLineNumber() + ")");
        interestingSitesPrinted++;
        if (interestingSitesPrinted <= SITES_TO_PRINT) {
          continue;
        }
        if (fileName == null || "View.java".equals(fileName)) {
          continue;
        }
        String methodName = e.getMethodName();
        if (skipMethods.contains(methodName)) {
          continue;
        }
        break;
      }
    }
    private static void extractViewPattern(int depth, ViewTrace trace, StringBuilder p) {
      if (!processedViewsForPatterns.add(trace)) {
        p.append("(ALIASED) ");
      }

      p.append(trace.realView.getClass() + " size = " + trace.realView.size() + "\n");
      indent(depth, p);

      p.append("    use:");
      if (trace.materializeCount == 0 && trace.sumCount == 0 && trace.getCount == 0) {
        p.append(" UNUSED");
      } else {
        if (trace.getCount > 0) {
          p.append(" get");
        }
        if (trace.materializeCount > 0) {
          p.append(" materialize");
        }
        if (trace.sumCount > 0) {
          p.append(" sum");
        }
      }
      p.append("\n");

      if (false) {
        p.append("    allocationSite =");
        Site.printSite(trace.allocationSite, p);
        p.append("\n");
        indent(depth, p);
      }

      RArray view = trace.realView;
      Class viewClass = view.getClass();
      Field[] fields = getAllFields(viewClass);
      boolean printedField = false;

      for (Field f : fields) {
        if (f.isSynthetic()) {
          continue;
        }
        Class fieldClass = f.getType();
        if (RArray.class.isAssignableFrom(fieldClass)) {
          continue; // these later
        }
        indent(depth, p);
        p.append("    " + f.getName() + " ");
        try {
          f.setAccessible(true);
          Object o = f.get(view);
          p.append(o == null ? "null (" + fieldClass + ")" : o.getClass());
          p.append("\n");
          printedField = true;
        } catch (IllegalAccessException e) {
          assert Utils.check(false, "can't read a view field " + e);
        }
      }

      boolean printNewline = printedField;
      for (Field f : fields) {
        if (f.isSynthetic()) {
          continue;
        }
        Class fieldClass = f.getType();
        if (!RArray.class.isAssignableFrom(fieldClass)) {
          continue;
        }
        if (printNewline) {
          p.append("\n");
          printNewline = false;
        }
        indent(depth, p);
        p.append("    " + f.getName() + " ");
        try {
          f.setAccessible(true);
          Object o = f.get(view);
          if (o instanceof TracingView) {
            p.append("VIEW ");
            TracingView child = (TracingView) o;
            extractViewPattern(depth + 2, child.getTrace(), p);
          } else {
            p.append("ARRAY " + o.getClass() + " size = " + ((RArray) o).size());
            if (o instanceof View) {
              ps.println("MISSED VIEW " + o);
            }
          }
          p.append("\n");
        } catch (IllegalAccessException e) {
          assert Utils.check(false, "can't read a view field " + e);
        }
      }
    }
 private static void indent(int depth, StringBuilder p) {
   for (int i = 0; i < depth; i++) {
     p.append(" ");
   }
 }
 public static void printSite(Site s) {
   StringBuilder b = new StringBuilder();
   printSite(s, b);
   ps.println(b.toString());
 }