//$Id: SQLFunction.java 10775 2006-11-08 16:56:52Z [email protected] $
package org.hibernate.dialect.function;
import java.util.List;
import org.hibernate.QueryException;
import org.hibernate.engine.Mapping;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.type.Type;
/**
* Provides support routines for the HQL functions as used
* in the various SQL Dialects
*
* Provides an interface for supporting various HQL functions that are
* translated to SQL. The Dialect and its sub-classes use this interface to
* provide details required for processing of the function.
*
* @author David Channon
*/
public 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.
*
* @param columnType the type of the first argument
* @param mapping The mapping source.
* @return The type to be expected as a return.
* @throws org.hibernate.QueryException Indicates an issue resolving the return type.
*/
public Type getReturnType(Type columnType, Mapping mapping) throws QueryException;
/**
* Does this function have any arguments?
*
* @return True if the function expects to have parameters; false otherwise.
*/
public boolean hasArguments();
/**
* If there are no arguments, are parens required?
*
* @return True if a no-arg call of this function requires parentheses.
*/
public boolean hasParenthesesIfNoArguments();
/**
* Render the function call as SQL fragment.
*
* @param args The function arguments
* @param factory The SessionFactory
* @return The rendered function call
* @throws org.hibernate.QueryException Indicates a problem rendering the
* function call.
*/
public String render(List args, SessionFactoryImplementor factory) throws QueryException;
}
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