Package org.apache.calcite.tools

Class Hoist

java.lang.Object

org.apache.calcite.tools.Hoist

@Enclosing
public class Hoist
extends Object

Utility that extracts constants from a SQL query.

Simple use:

final String sql =
"select 'x' from emp where deptno < 10";
final Hoist.Hoisted hoisted =
Hoist.create(Hoist.config()).hoist();
print(hoisted); // "select ?0 from emp where deptno < ?1"

Calling Hoist.Hoisted.toString() generates a string that is similar to SQL where a user has manually converted all constants to bind variables, and which could then be executed using PreparedStatement.execute(). That is not a goal of this utility, but see [CALCITE-963] Hoist literals.

For more advanced formatting, use Hoist.Hoisted.substitute(Function).

Adjust Hoist.Config to use a different parser or parsing options.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Hoist.Config	Configuration.
static class	Hoist.Hoisted	Result of hoisting.
static class	Hoist.Variable	Variable.

Method Summary

Modifier and Type	Method	Description
static Hoist.Config	config()	Creates a Config.
static Hoist	create(Hoist.Config config)	Creates a Hoist.
Hoist.Hoisted	hoist(String sql)	Hoists literals in a given SQL string, returning a Hoist.Hoisted.
static String	ordinalString(Hoist.Variable v)	Converts a Hoist.Variable to a string "?N", where N is the Hoist.Variable.ordinal.
static String	ordinalStringIfChar(Hoist.Variable v)	Converts a Hoist.Variable to a string "?N", where N is the Hoist.Variable.ordinal, if the fragment is a character literal.

Methods inherited from class java.lang.Object

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

Method Details

config

public static Hoist.Config config()

Creates a Config.

create

public static Hoist create(Hoist.Config config)

Creates a Hoist.

ordinalString

public static String ordinalString(Hoist.Variable v)

Converts a Hoist.Variable to a string "?N", where N is the Hoist.Variable.ordinal.

ordinalStringIfChar

public static String ordinalStringIfChar(Hoist.Variable v)

Converts a Hoist.Variable to a string "?N", where N is the Hoist.Variable.ordinal, if the fragment is a character literal. Other fragments are unchanged.

hoist

public Hoist.Hoisted hoist(String sql)

Hoists literals in a given SQL string, returning a Hoist.Hoisted.