Class QueryEngine

java.lang.Object

com.loomcache.server.query.QueryEngine

public class QueryEngine
extends Object

Executes QueryPlan against a DistributedMap. Handles scanning entries, applying predicates, projecting columns, sorting, limiting, and aggregation.

Constructor Summary

Constructors

Constructor	Description
QueryEngine()

Method Summary

Modifier and Type	Method	Description
static Comparator<SqlRow>	buildOrderByComparator(List<QueryPlan.OrderBy> orderByList)	Applies ORDER BY clauses to a list of rows using a single composite comparator.
static int	compareQueryValues(Object left, Object right)
<K> SqlResult	execute(QueryPlan queryPlan, DistributedMap<K,?> map)	Executes a query plan and returns a result set.
static List<String>	getColumnNames(List<SqlRow> rows)
static List<SqlColumnType>	getColumnTypes(List<SqlRow> rows)
static SqlRow	projectColumns(SqlRow row, List<String> selectedColumns)	Projects a row to include only selected columns.
static int	validateProjectedRowWidth(SqlRow row)

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

QueryEngine

public QueryEngine()

Method Details

execute

public <K> SqlResult execute(QueryPlan queryPlan,
 DistributedMap<K,?> map)

Executes a query plan and returns a result set.

Parameters:

queryPlan - the parsed and prepared query plan

map - the map to query

Returns:

a SqlResult containing the result rows

projectColumns

public static SqlRow projectColumns(SqlRow row,
 List<String> selectedColumns)

Projects a row to include only selected columns.

validateProjectedRowWidth

public static int validateProjectedRowWidth(SqlRow row)

buildOrderByComparator

public static Comparator<SqlRow> buildOrderByComparator(List<QueryPlan.OrderBy> orderByList)

Applies ORDER BY clauses to a list of rows using a single composite comparator.

compareQueryValues

public static int compareQueryValues(Object left,
 Object right)

getColumnNames

public static List<String> getColumnNames(List<SqlRow> rows)

getColumnTypes

public static List<SqlColumnType> getColumnTypes(List<SqlRow> rows)