package org.aksw.sparqlify.algebra.sql.exprs2; import org.aksw.sparqlify.core.TypeToken; import org.apache.jena.atlas.io.IndentedWriter; public interface SqlAggregator { SqlExpr getExpr(); /** * This method must always return the same result * * @return */ TypeToken getDatatype(); void asString(IndentedWriter writer); SqlAggregator copy(SqlExpr arg); }