org.hibernate.dialect.function
Class VarArgsSQLFunction

java.lang.Object
  org.hibernate.dialect.function.VarArgsSQLFunction

All Implemented Interfaces:

SQLFunction

public class VarArgsSQLFunction
extends Object
implements SQLFunction

Support for slightly more general templating than StandardSQLFunction, with an unlimited number of arguments.

Author:

Gavin King

Constructor Summary

VarArgsSQLFunction(String begin, String sep, String end)
Constructs a VarArgsSQLFunction instance with a 'dynamic' return type.

VarArgsSQLFunction(Type type, String begin, String sep, String end)
Constructs a VarArgsSQLFunction instance with a 'static' return type.

Method Summary

Type	getReturnType(Type columnType, Mapping mapping) The return type of the function.
boolean	hasArguments() Does this function have any arguments?
boolean	hasParenthesesIfNoArguments() If there are no arguments, are parens required?
String	render(List args, SessionFactoryImplementor factory) Render the function call as SQL fragment.
protected String	transformArgument(String argument) Called from render(java.util.List, org.hibernate.engine.SessionFactoryImplementor) to allow applying a change or transformation to each individual argument.

Methods inherited from class java.lang.Object

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

Constructor Detail

VarArgsSQLFunction

public VarArgsSQLFunction(Type type,
                          String begin,
                          String sep,
                          String end)

Constructs a VarArgsSQLFunction instance with a 'static' return type. An example of a 'static' return type would be something like an UPPER function which is always returning a SQL VARCHAR and thus a string type.

Parameters:

type - The return type.

begin - The beginning of the function templating.

sep - The separator for each individual function argument.

end - The end of the function templating.

VarArgsSQLFunction

public VarArgsSQLFunction(String begin,
                          String sep,
                          String end)

Constructs a VarArgsSQLFunction instance with a 'dynamic' return type. For a dynamic return type, the type of the arguments are used to resolve the type. An example of a function with a 'dynamic' return would be MAX or MIN which return a double or an integer etc based on the types of the arguments.

Parameters:

begin - The beginning of the function templating.

sep - The separator for each individual function argument.

end - The end of the function templating.

See Also:

Specifically, the 'columnType' argument is the 'dynamic' type.

Method Detail

getReturnType

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

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.

Specified by:

getReturnType in interface SQLFunction

Parameters:

columnType - 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()

Does this function have any arguments?

Always returns true here.

Specified by:

hasArguments in interface SQLFunction

Returns:

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

hasParenthesesIfNoArguments

public boolean hasParenthesesIfNoArguments()

If there are no arguments, are parens required?

Always returns true here.

Specified by:

hasParenthesesIfNoArguments in interface SQLFunction

Returns:

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

render

public String render(List args,
                     SessionFactoryImplementor factory)
              throws QueryException

Render the function call as SQL fragment.

Specified by:

render in interface SQLFunction

Parameters:

args - The function arguments

factory - The SessionFactory

Returns:

The rendered function call

Throws:

QueryException - Indicates a problem rendering the function call.

transformArgument

protected String transformArgument(String argument)

Called from render(java.util.List, org.hibernate.engine.SessionFactoryImplementor) to allow applying a change or transformation to each individual argument.

Parameters:

argument - The argument being processed.

Returns:

The transformed argument; may be the same, though should never be null.