org.hibernate.dialect.function

Class SQLFunctionTemplate

java.lang.Object

org.hibernate.dialect.function.SQLFunctionTemplate

All Implemented Interfaces:

SQLFunction

public class SQLFunctionTemplate
extends Object
implements SQLFunction

Represents HQL functions that can have different representations in different SQL dialects where that difference can be handled via a template/pattern.

E.g. in HQL we can define function concat(?1, ?2) to concatenate two strings p1 and p2. Dialects would register different versions of this class *using the same name* (concat) but with different templates or patterns; (?1 || ?2) for Oracle, concat(?1, ?2) for MySql, (?1 + ?2) for MS SQL. Each dialect will define a template as a string (exactly like above) marking function parameters with '?' followed by parameter's index (first index is 1).

Author:

Alexey Loubyansky

Constructor Summary

Constructors

Constructor and Description
SQLFunctionTemplate(Type type, String template) Constructs a SQLFunctionTemplate
SQLFunctionTemplate(Type type, String template, boolean hasParenthesesIfNoArgs) Constructs a SQLFunctionTemplate

Method Summary

Modifier and Type	Method and Description
Type	getReturnType(Type argumentType, Mapping mapping) The return type of the function.
boolean	hasArguments() Does this function have any arguments?
boolean	hasParenthesesIfNoArguments() If there are no arguments, are parentheses required?
String	render(Type argumentType, List args, SessionFactoryImplementor factory) Render the function call as SQL fragment.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

SQLFunctionTemplate

public SQLFunctionTemplate(Type type,
                           String template)

Constructs a SQLFunctionTemplate

Parameters:

type - The functions return type

template - The function template

SQLFunctionTemplate

public SQLFunctionTemplate(Type type,
                           String template,
                           boolean hasParenthesesIfNoArgs)

Constructs a SQLFunctionTemplate

Parameters:

type - The functions return type

template - The function template

hasParenthesesIfNoArgs - If there are no arguments, are parentheses required?

Method Detail

render

public String render(Type argumentType,
                     List args,
                     SessionFactoryImplementor factory)

Description copied from interface: SQLFunction

Render the function call as SQL fragment.

Note, the 'firstArgumentType' parameter should match the one passed into SQLFunction.getReturnType(org.hibernate.type.Type, org.hibernate.engine.spi.Mapping)

Specified by:

render in interface SQLFunction

Parameters:

argumentType - The type of the first argument

args - The function arguments

factory - The SessionFactory

Returns:

The rendered function call

getReturnType

public Type getReturnType(Type argumentType,
                          Mapping mapping)
                   throws QueryException

Description copied from interface: SQLFunction

The return type of the function. May be either a concrete type which is preset, or variable depending upon the type of the first function argument.

Note, the 'firstArgumentType' parameter should match the one passed into SQLFunction.render(org.hibernate.type.Type, java.util.List, org.hibernate.engine.spi.SessionFactoryImplementor)

Specified by:

getReturnType in interface SQLFunction

Parameters:

argumentType - The type of the first argument

mapping - The mapping source.

Returns:

The type to be expected as a return.

Throws:

QueryException - Indicates an issue resolving the return type.

hasArguments

public boolean hasArguments()

Description copied from interface: SQLFunction

Does this function have any arguments?

Specified by:

hasArguments in interface SQLFunction

Returns:

True if the function expects to have parameters; false otherwise.

hasParenthesesIfNoArguments

public boolean hasParenthesesIfNoArguments()

Description copied from interface: SQLFunction

If there are no arguments, are parentheses required?

Specified by:

hasParenthesesIfNoArguments in interface SQLFunction

Returns:

True if a no-arg call of this function requires parentheses.

toString

public String toString()

Overrides:

toString in class Object