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/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or .
*/
package org.hibernate.hql.internal.ast.tree;
import java.util.ArrayList;
import java.util.List;
import org.hibernate.hql.internal.antlr.SqlTokenTypes;
import org.hibernate.hql.internal.ast.util.ASTPrinter;
import org.hibernate.hql.internal.ast.util.TokenPrinters;
import antlr.collections.AST;
/**
* Common behavior - a node that contains a list of select expressions.
*
* @author josh
*/
public abstract class SelectExpressionList extends HqlSqlWalkerNode {
private List parameterPositions = new ArrayList();
/**
* 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();
ArrayList list = new ArrayList();
int p = 0;
for ( AST n = firstChild; n != null; n = n.getNextSibling() ) {
if ( n instanceof SelectExpression ) {
list.add( (SelectExpression) n );
}
else if ( n instanceof ParameterNode ) {
parameterPositions.add( p );
}
else {
throw new IllegalStateException(
"Unexpected AST: " + n.getClass().getName() + " "
+ TokenPrinters.SQL_TOKEN_PRINTER.showAsString( n, "" )
);
}
p++;
}
return list.toArray( new SelectExpression[list.size()] );
}
/**
* The total number of parameter projections of this expression.
*
* @return The number of parameters in this select clause.
*/
public int getTotalParameterCount() {
return parameterPositions.size();
}
/**
* The position of parameters within the list of select expressions of this clause
*
* @return a list of positions representing the mapping from order of occurence to position
*/
public List getParameterPositions() {
return parameterPositions;
}
/**
* 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();
}