//$Id: CastFunction.java,v 1.7 2005/07/04 02:54:27 oneovthafew Exp $

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;

import org.hibernate.type.TypeFactory;



/**

 * ANSI-SQL style <tt>cast(foo as type)</tt> where the type is

 * a Hibernate type

 * @author Gavin King

 */

public class CastFunction implements SQLFunction {



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

		return columnType; //note there is a wierd implementation in the client side

	}



	public boolean hasArguments() {

		return true;

	}



	public boolean hasParenthesesIfNoArguments() {

		return true;

	}



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

		if ( args.size()!=2 ) {

			throw new QueryException("cast() requires two arguments");

		}

		String type = (String) args.get(1);

		int[] sqlTypeCodes = TypeFactory.heuristicType(type).sqlTypes(factory);

		if ( sqlTypeCodes.length!=1 ) {

			throw new QueryException("invalid Hibernate type for cast()");

		}

		String sqlType = factory.getDialect().getCastTypeName( sqlTypeCodes[0] );

		if (sqlType==null) {

			//TODO: never reached, since getTypeName() actually throws an exception!

			sqlType = type;

		}

		/*else {

			//trim off the length/precision/scale

			int loc = sqlType.indexOf('(');

			if (loc>-1) {

				sqlType = sqlType.substring(0, loc);

			}

		}*/

		return "cast(" + args.get(0) + " as " + sqlType + ')';

	}



}

