// $Id: SelectExpressionList.java 7460 2005-07-12 20:27:29Z steveebersole $
package org.hibernate.hql.ast.tree;
import java.util.ArrayList;
import org.hibernate.hql.antlr.SqlTokenTypes;
import org.hibernate.hql.ast.util.ASTPrinter;
import antlr.collections.AST;
/**
* Common behavior - a node that contains a list of select expressions.
*
* @author josh Nov 6, 2004 8:51:00 AM
*/
public abstract class SelectExpressionList extends HqlSqlWalkerNode {
/**
* Returns an array of SelectExpressions gathered from the children of the given parent AST node.
*
* @return an array of SelectExpressions gathered from the children of the given parent AST node.
*/
public SelectExpression[] collectSelectExpressions() {
// Get the first child to be considered. Sub-classes may do this differently in order to skip nodes that
// are not select expressions (e.g. DISTINCT).
AST firstChild = getFirstSelectExpression();
AST parent = this;
ArrayList list = new ArrayList( parent.getNumberOfChildren() );
for ( AST n = firstChild; n != null; n = n.getNextSibling() ) {
if ( n instanceof SelectExpression ) {
list.add( n );
}
else {
throw new IllegalStateException( "Unexpected AST: " + n.getClass().getName() + " " + new ASTPrinter( SqlTokenTypes.class ).showAsString( n, "" ) );
}
}
return ( SelectExpression[] ) list.toArray( new SelectExpression[list.size()] );
}
/**
* Returns the first select expression node that should be considered when building the array of select
* expressions.
*
* @return the first select expression node that should be considered when building the array of select
* expressions
*/
protected abstract AST getFirstSelectExpression();
}
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