@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<String, DocsumDefinition> e : definitionsByName.entrySet() ) {
            if (!sb.isEmpty()) {
                sb.append(",");
            }
            sb.append("[").append(e.getKey()).append(",").append(e.getValue().name()).append("]");
        }
        return sb.toString();
    }
Makes data available for decoding for the given hit.

@param summaryClass the requested summary class
@param data docsum data from backend
@param hit the Hit corresponding to this document summary
@return Error message or null on success.
@throws ConfigurationException if the summary class of this hit is missing
container-search/src/main/java/com/yahoo/prelude/fastsearch/DocsumDefinitionSet.java