Hibernate example source code file (SelectExpressionList.java)

This example Hibernate source code file (SelectExpressionList.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

arraylist, arraylist, ast, ast, astprinter, hqlsqlwalkernode, hqlsqlwalkernode, illegalstateexception, selectexpression, selectexpression, selectexpressionlist, unexpected, util

The Hibernate SelectExpressionList.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.hql.internal.ast.tree;
import java.util.ArrayList;
import org.hibernate.hql.internal.antlr.SqlTokenTypes;
import org.hibernate.hql.internal.ast.util.ASTPrinter;
import antlr.collections.AST;

/**
 * Common behavior - a node that contains a list of select expressions.
 *
 * @author josh
 */
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();

}