/**
* Constructs a table aggregator and aggregates the table.
*
* @param groupByColumns An ordered list of columns to group by.
* @param aggregateColumns A set of columns to aggregate.
* @param table The table.
*/
public TableAggregator(
List<String> groupByColumns, Set<String> aggregateColumns, DataTable table) {
this.groupByColumns = groupByColumns;
this.aggregateColumns = aggregateColumns;
tree = new AggregationTree(aggregateColumns, table);
// Iterate over all rows and aggregate each row via the aggregation tree.
for (TableRow row : table.getRows()) {
tree.aggregate(
getRowPath(row, table, groupByColumns.size() - 1), getValuesToAggregate(row, table));
}
}
/**
* Returns the aggregation value of a specific column and type.
*
* @param path The aggregation path.
* @param columnId The requested column id.
* @param type The requested aggregation type.
* @return The aggregation values of a specific column.
*/
public Value getAggregationValue(AggregationPath path, String columnId, AggregationType type) {
return tree.getNode(path).getAggregationValue(columnId, type);
}
/**
* Returns a set containing the paths to all the leaves in the tree.
*
* @return A set containing the paths to all the leaves in the tree.
*/
public Set<AggregationPath> getPathsToLeaves() {
return tree.getPathsToLeaves();
}