// $Id: SelectExpression.java 7460 2005-07-12 20:27:29Z steveebersole $
package org.hibernate.hql.ast.tree;
import org.hibernate.type.Type;
import antlr.SemanticException;
/**
* Represents an element of a projection list, i.e. a select expression.
*
* @author josh Sep 21, 2004 9:00:13 PM
*/
public interface SelectExpression {
/**
* Returns the data type of the select expression.
*
* @return The data type of the select expression.
*/
Type getDataType();
/**
* Appends AST nodes that represent the columns after the current AST node.
* (e.g. 'as col0_O_')
*
* @param i The index of the select expression in the projection list.
*/
void setScalarColumnText(int i) throws SemanticException;
/**
* Returns the FROM element that this expression refers to.
*
* @return The FROM element.
*/
FromElement getFromElement();
/**
* Returns true if the element is a constructor (e.g. new Foo).
*
* @return true if the element is a constructor (e.g. new Foo).
*/
boolean isConstructor();
/**
* Returns true if this select expression represents an entity that can be returned.
*
* @return true if this select expression represents an entity that can be returned.
*/
boolean isReturnableEntity() throws SemanticException;
/**
* Sets the text of the node.
*
* @param text the new node text.
*/
void setText(String text);
boolean isScalar() throws SemanticException;
void setAlias(String alias);
String getAlias();
}
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