public List<String> list(final String entity, final String field) {
   final EntityChunk chunk = data.get(entity);
   if (chunk == null) {
     return Collections.<String>emptyList();
   }
   final List<String> fieldValues = chunk.getValue(field);
   if (fieldValues != null) {
     return fieldValues;
   }
   return Collections.<String>emptyList();
 }
 public int count(final String entity, final String field) {
   final EntityChunk chunk = data.get(entity);
   if (chunk == null) {
     return 0;
   }
   final List<String> fieldValues = chunk.getValue(field);
   if (fieldValues != null) {
     return fieldValues.size();
   }
   return 0;
 }
 public int sum(final String entity, final String field) {
   final EntityChunk chunk = data.get(entity);
   if (chunk == null) {
     return 0;
   }
   final List<String> fieldValues = chunk.getValue(field);
   if (fieldValues != null) {
     int sum = 0;
     for (final String fieldValue : fieldValues) {
       sum += Integer.parseInt(fieldValue);
     }
     return sum;
   }
   return 0;
 }
 public List<String> containsValue(final String entity, final String field, final String value) {
   final EntityChunk chunk = data.get(entity);
   if (chunk == null) {
     return Collections.<String>emptyList();
   }
   final List<String> fieldValues = chunk.getValue(field);
   if (fieldValues != null) {
     final List<String> returnValues = new ArrayList<>();
     for (final String fieldValue : fieldValues) {
       if (fieldValue.contains(value)) {
         returnValues.add(fieldValue);
       }
     }
     return returnValues;
   }
   return Collections.<String>emptyList();
 }