org.datanucleus.store.rdbms.query

Interface QueryGenerator

All Known Implementing Classes:

QueryToSQLMapper

public interface QueryGenerator

Interface for a generator of query statements.

Method Summary

Modifier and Type	Method and Description
void	bindParameter(String paramName, Class type) Method to bind the specified parameter to the defined type.
void	bindVariable(String varName, org.datanucleus.metadata.AbstractClassMetaData cmd, SQLTable sqlTbl, JavaTypeMapping mapping) Method to bind the specified variable to the table and mapping.
SQLExpression	bindVariable(UnboundExpression expr, Class type) Method to bind the specified unbound variable (as cross join).
org.datanucleus.ClassLoaderResolver	getClassLoaderResolver() Accessor for the ClassLoader resolver to use when looking up classes.
org.datanucleus.query.compiler.CompilationComponent	getCompilationComponent() Accessor for the current query component being compiled.
org.datanucleus.ExecutionContext	getExecutionContext() Accessor for the ExecutionContext for this query.
Object	getProperty(String name) Accessor for a property affecting the query compilation.
String	getQueryLanguage() Accessor for the query language that this query pertains to.
SQLTable	getSQLTableForAlias(String alias) Method to return the SQLTable for the specified primary expression "alias".
Class	getTypeOfVariable(String varName) Accessor for the type of a variable if already known (declared?).
Object	getValueForExtension(String key) Accessor for the value of the specified query extension (or null if not defined).
boolean	hasExplicitJoins() Accessor for whether the query has explicit joins.
boolean	hasExtension(String key) Accessor for whether the query being generated has the specified extension.
Class	resolveClass(String className) Convenience method to resolve a class name.
void	useParameterExpressionAsLiteral(SQLLiteral paramLiteral) Method to instruct the generator to convert the provided parameter expression to just be a literal using the value of the parameter (hence the statement cannot be precompilable since the value needs to be known).

Method Detail

getQueryLanguage

String getQueryLanguage()

Accessor for the query language that this query pertains to. Can be used to decide how to handle the input.

Returns:

The query language

getClassLoaderResolver

org.datanucleus.ClassLoaderResolver getClassLoaderResolver()

Accessor for the ClassLoader resolver to use when looking up classes.

Returns:

The classloader resolver

getExecutionContext

org.datanucleus.ExecutionContext getExecutionContext()

Accessor for the ExecutionContext for this query.

Returns:

ExecutionContext

getCompilationComponent

org.datanucleus.query.compiler.CompilationComponent getCompilationComponent()

Accessor for the current query component being compiled.

Returns:

Component being compiled (if any)

getProperty

Object getProperty(String name)

Accessor for a property affecting the query compilation. This can be something like whether there is an OR in the filter, which can then impact on the type of SQL used.

Parameters:

name - The property name

Returns:

Its value

useParameterExpressionAsLiteral

void useParameterExpressionAsLiteral(SQLLiteral paramLiteral)

Method to instruct the generator to convert the provided parameter expression to just be a literal using the value of the parameter (hence the statement cannot be precompilable since the value needs to be known).

Parameters:

paramLiteral - The parameter expression

getTypeOfVariable

Class getTypeOfVariable(String varName)

Accessor for the type of a variable if already known (declared?).

Parameters:

varName - Name of the variable

Returns:

The type if it is known

bindVariable

void bindVariable(String varName,
                  org.datanucleus.metadata.AbstractClassMetaData cmd,
                  SQLTable sqlTbl,
                  JavaTypeMapping mapping)

Method to bind the specified variable to the table and mapping.

Parameters:

varName - Variable name

cmd - Metadata for this variable type

sqlTbl - Table for this variable

mapping - The mapping of this variable in the table

bindVariable

SQLExpression bindVariable(UnboundExpression expr,
                           Class type)

Method to bind the specified unbound variable (as cross join).

Parameters:

expr - Unbound expression

type - The type to bind as

Returns:

The bound expression to use instead

hasExplicitJoins

boolean hasExplicitJoins()

Accessor for whether the query has explicit joins. A JPQL query has explicit joins, whereas a JDOQL query has variables and hence implicit joins. If not then has implicit joins, meaning that they could potentially be rebound later if prematurely bound in a particular way.

Returns:

Whether the query has explicit joins

bindParameter

void bindParameter(String paramName,
                   Class type)

Method to bind the specified parameter to the defined type. If the parameter is already bound (declared in the query perhaps, or bound via an earlier usage) then does nothing.

Parameters:

paramName - Name of the parameter

type - The type (or subclass)

getSQLTableForAlias

SQLTable getSQLTableForAlias(String alias)

Method to return the SQLTable for the specified primary expression "alias".

Parameters:

alias - The alias ("this", fieldName)

Returns:

The SQLTable for this if it exists

resolveClass

Class resolveClass(String className)

Convenience method to resolve a class name.

Parameters:

className - The class name

Returns:

The class it relates to (if found)

hasExtension

boolean hasExtension(String key)

Accessor for whether the query being generated has the specified extension.

Parameters:

key - Extension name

Returns:

Whether it is present

getValueForExtension

Object getValueForExtension(String key)

Accessor for the value of the specified query extension (or null if not defined).

Parameters:

key - Extension name

Returns:

The value for the extension