@Override
  public int occurrences(Object element) {
    // expensive!!
    int count = 0;
    for (Object v : values) {
      if (element == null ? v == null : element.equals(v)) {
        count++;
      }
    }
    return count;
  }
Getter for property modifiable. Since a QRegion as a collection represents an unmodifiable
facade on the values of this region, return false.

@return Value of property modifiable.
geode-core/src/main/java/org/apache/geode/cache/query/internal/QRegion.java