Package org.apache.calcite.linq4j

Class QueryProviderImpl

java.lang.Object

org.apache.calcite.linq4j.QueryProviderImpl

All Implemented Interfaces:

QueryProvider

Direct Known Subclasses:

JdbcQueryProvider

public abstract class QueryProviderImpl
extends java.lang.Object
implements QueryProvider

Partial implementation of QueryProvider.

Derived class needs to implement QueryProvider.executeQuery(org.apache.calcite.linq4j.Queryable<T>).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	QueryProviderImpl.QueryableImpl<T>	Binds an expression to this query provider.

Constructor Summary

Constructors

Constructor	Description
QueryProviderImpl()	Creates a QueryProviderImpl.

Method Summary

Modifier and Type	Method	Description
<T> Queryable<T>	createQuery(Expression expression, java.lang.Class<T> rowType)	Constructs a Queryable object that can evaluate the query represented by a specified expression tree.
<T> Queryable<T>	createQuery(Expression expression, java.lang.reflect.Type rowType)	Constructs a Queryable object that can evaluate the query represented by a specified expression tree.
<T> T	execute(Expression expression, java.lang.Class<T> type)	Executes the query represented by a specified expression tree.
<T> T	execute(Expression expression, java.lang.reflect.Type type)	Executes the query represented by a specified expression tree.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.calcite.linq4j.QueryProvider

executeQuery

Constructor Detail

QueryProviderImpl

public QueryProviderImpl()

Creates a QueryProviderImpl.

Method Detail

createQuery

public <T> Queryable<T> createQuery(Expression expression,
                                    java.lang.Class<T> rowType)

Description copied from interface: QueryProvider

Constructs a Queryable object that can evaluate the query represented by a specified expression tree.

NOTE: The RawQueryable.getExpression() property of the returned Queryable object is equal to expression.

Specified by:

createQuery in interface QueryProvider

Type Parameters:

T - Row type

Parameters:

expression - Expression

rowType - Row type

Returns:

Queryable

createQuery

public <T> Queryable<T> createQuery(Expression expression,
                                    java.lang.reflect.Type rowType)

Description copied from interface: QueryProvider

Constructs a Queryable object that can evaluate the query represented by a specified expression tree. The row type may contain generic information.

Specified by:

createQuery in interface QueryProvider

Type Parameters:

T - Row type

Parameters:

expression - Expression

rowType - Row type

Returns:

Queryable

execute

public <T> T execute(Expression expression,
                     java.lang.Class<T> type)

Description copied from interface: QueryProvider

Executes the query represented by a specified expression tree.

This method executes queries that return a single value (instead of an enumerable sequence of values). Expression trees that represent queries that return enumerable results are executed when the Queryable object that contains the expression tree is enumerated.

The Queryable standard query operator methods that return singleton results call execute. They pass it a MethodCallExpression that represents a linq4j query.

Specified by:

execute in interface QueryProvider

execute

public <T> T execute(Expression expression,
                     java.lang.reflect.Type type)

Description copied from interface: QueryProvider

Executes the query represented by a specified expression tree. The row type may contain type parameters.

Specified by:

execute in interface QueryProvider