Package org.datanucleus.store.rdbms.sql.expression

Class SQLExpressionFactory

java.lang.Object

org.datanucleus.store.rdbms.sql.expression.SQLExpressionFactory

public class SQLExpressionFactory
extends Object

Factory for creating SQL expressions/literals. These are typically called when we are building up an SQL statement and we want to impose conditions using the fields of a class, and values for the field.

Constructor Summary

Constructors

Constructor	Description
SQLExpressionFactory(RDBMSStoreManager storeMgr)	Constructor for an SQLExpressionFactory.

Method Summary

Modifier and Type	Method	Description
JavaTypeMapping	getMappingForType(Class cls)
JavaTypeMapping	getMappingForType(Class cls, boolean useCached)	Accessor for a mapping to use in a query expression.
protected SQLMethod	getMethod(String className, String methodName, List args)	Accessor for the method defined by the class/method names and supplied args.
SQLExpression	invokeMethod(SQLStatement stmt, String className, String methodName, SQLExpression expr, List args)	Accessor for the result of an SQLMethod call on the supplied expression with the supplied args.
SQLExpression	invokeOperation(String name, SQLExpression expr, SQLExpression expr2)	Accessor for the result of an SQLOperation call on the supplied expression with the supplied args.
boolean	isMethodRegistered(String className, String methodName)
SQLExpression	newExpression(SQLStatement stmt, SQLTable sqlTbl, JavaTypeMapping mapping)	Factory for an expression representing a mapping on a table.
SQLExpression	newExpression(SQLStatement stmt, SQLTable sqlTbl, JavaTypeMapping mapping, JavaTypeMapping parentMapping)	Factory for an expression representing a mapping on a table.
SQLExpression	newLiteral(SQLStatement stmt, JavaTypeMapping mapping, Object value)	Factory for a literal representing a value.
SQLExpression	newLiteralParameter(SQLStatement stmt, JavaTypeMapping mapping, Object value, String paramName)	Factory for a literal as an input parameter.
void	registerMethod(String className, String methodName, SQLMethod method)	Method to allow a user to register an SQLMethod at runtime without utilising the plugin mechanism.
SQLExpression	replaceParameterLiteral(ParameterLiteral paramLit, SQLExpression comparisonExpr)	Convenience method to replace the provided ParameterLiteral with a "parameter-based" literal using the supplied mapping (generated before its type was known).

Methods inherited from class java.lang.Object

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

Constructor Detail

SQLExpressionFactory

public SQLExpressionFactory(RDBMSStoreManager storeMgr)

Constructor for an SQLExpressionFactory. Also loads up the defined SQL methods [extension-point: "org.datanucleus.store.rdbms.sql_method"] and caches the keys. Also loads up the defined SQL operations [extension-point: "org.datanucleus.store.rdbms.sql_operation"] and caches the keys.

Parameters:

storeMgr - RDBMS Manager

Method Detail

newExpression

public SQLExpression newExpression(SQLStatement stmt,
                                   SQLTable sqlTbl,
                                   JavaTypeMapping mapping)

Factory for an expression representing a mapping on a table.

Parameters:

stmt - The statement

sqlTbl - The table

mapping - The mapping

Returns:

The expression

newExpression

public SQLExpression newExpression(SQLStatement stmt,
                                   SQLTable sqlTbl,
                                   JavaTypeMapping mapping,
                                   JavaTypeMapping parentMapping)

Factory for an expression representing a mapping on a table.

Parameters:

stmt - The statement

sqlTbl - The table

mapping - The mapping

parentMapping - Optional parent mapping of this mapping (e.g when handling an implementation of an interface)

Returns:

The expression

newLiteral

public SQLExpression newLiteral(SQLStatement stmt,
                                JavaTypeMapping mapping,
                                Object value)

Factory for a literal representing a value. To create a NullLiteral pass in a null mapping.

Parameters:

stmt - The statement

mapping - The mapping

value - The value

Returns:

The literal

newLiteralParameter

public SQLExpression newLiteralParameter(SQLStatement stmt,
                                         JavaTypeMapping mapping,
                                         Object value,
                                         String paramName)

Factory for a literal as an input parameter. If the mapping (type of parameter) is not known at this point then put in null and it will return a ParameterLiteral.

Parameters:

stmt - The statement

mapping - The mapping

value - Value of the literal (if known)

paramName - The parameter name

Returns:

The literal

replaceParameterLiteral

public SQLExpression replaceParameterLiteral(ParameterLiteral paramLit,
                                             SQLExpression comparisonExpr)

Convenience method to replace the provided ParameterLiteral with a "parameter-based" literal using the supplied mapping (generated before its type was known).

Parameters:

paramLit - The parameter literal

comparisonExpr - Expression we compare against

Returns:

The replacement expression

invokeMethod

public SQLExpression invokeMethod(SQLStatement stmt,
                                  String className,
                                  String methodName,
                                  SQLExpression expr,
                                  List args)

Accessor for the result of an SQLMethod call on the supplied expression with the supplied args. Throws a NucleusException is the method is not supported.

Parameters:

stmt - SQLStatement that this relates to

className - Class we are invoking the method on

methodName - Name of the method

expr - The expression we invoke the method on

args - Any arguments to the method call

Returns:

The result

isMethodRegistered

public boolean isMethodRegistered(String className,
                                  String methodName)

registerMethod

public void registerMethod(String className,
                           String methodName,
                           SQLMethod method)

Method to allow a user to register an SQLMethod at runtime without utilising the plugin mechanism. Will throw a NucleusUserException if this class+method already has an SQLMethod defined.

Parameters:

className - Class name (or null if "static")

methodName - Name of the method/function

method - The SQLMethod to invoke when this method is encountered

getMethod

protected SQLMethod getMethod(String className,
                              String methodName,
                              List args)

Accessor for the method defined by the class/method names and supplied args. Throws a NucleusException is the method is not supported. Note that if the class name passed in is not for a listed class with that method defined then will check all remaining defined methods for a superclass.

Parameters:

className - Class we are invoking the method on

methodName - Name of the method

args - Any arguments to the method call (ignored currently) TODO Check the arguments

Returns:

The method

invokeOperation

public SQLExpression invokeOperation(String name,
                                     SQLExpression expr,
                                     SQLExpression expr2)

Accessor for the result of an SQLOperation call on the supplied expression with the supplied args. Throws a NucleusException is the method is not supported.

Parameters:

name - Operation to be invoked

expr - The first expression to perform the operation on

expr2 - The second expression to perform the operation on

Returns:

The result

Throws:

UnsupportedOperationException - if the operation is not specified

getMappingForType

public JavaTypeMapping getMappingForType(Class cls,
                                         boolean useCached)

Accessor for a mapping to use in a query expression.

Parameters:

cls - The class that the mapping should represent.

useCached - Whether to use any cached mapping (if available)

Returns:

The mapping

getMappingForType

public JavaTypeMapping getMappingForType(Class cls)