Hibernate example source code file (ResultVariableRefNode.java)

This example Hibernate source code file (ResultVariableRefNode.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

a, hqlsqlwalkernode, illegalstateexception, override, resultvariablerefnode, resultvariablerefnode, selectexpression, semanticexception, semanticexception, string, string, stringbuffer, stringbuffer

The Hibernate ResultVariableRefNode.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, 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 org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.internal.util.StringHelper;
import antlr.SemanticException;

/**
 * Represents a reference to a result_variable as defined in the JPA 2 spec.
 * For example:
 * <code>
 * select v as value from tab1 order by value
 * </code>
 * <p/>
 * "value" used in the order by clause is a reference to the
 * result_variable, "value", defined in the select clause.
 *
 * @author Gail Badner
 */
public class ResultVariableRefNode extends HqlSqlWalkerNode {
	private SelectExpression selectExpression;

	/**
	 * Set the select expression that defines the result variable.
	 *
	 * @param selectExpression the select expression;
	 *        selectExpression.getAlias() must be non-null
	 * @throws SemanticException if selectExpression or
	 *         selectExpression.getAlias() is null.
	 */
	public void setSelectExpression(SelectExpression selectExpression) throws SemanticException {
		if ( selectExpression == null || selectExpression.getAlias() == null ) {
			throw new SemanticException( "A ResultVariableRefNode must refer to a non-null alias." );
		}
		this.selectExpression = selectExpression;
	}

	/**
	 *  {@inheritDoc}
	 */
	@Override
    public String getRenderText(SessionFactoryImplementor sessionFactory) {
		int scalarColumnIndex = selectExpression.getScalarColumnIndex();
		if ( scalarColumnIndex < 0 ) {
			throw new IllegalStateException(
					"selectExpression.getScalarColumnIndex() must be >= 0; actual = " + scalarColumnIndex
			);
		}
		return sessionFactory.getDialect().replaceResultVariableInOrderByClauseWithPosition() ?
			getColumnPositionsString( scalarColumnIndex ) :
			getColumnNamesString( scalarColumnIndex );

	}

	private String getColumnPositionsString(int scalarColumnIndex ) {
		int startPosition = getWalker().getSelectClause().getColumnNamesStartPosition( scalarColumnIndex );
		StringBuffer buf = new StringBuffer();
		int nColumns = getWalker().getSelectClause().getColumnNames()[ scalarColumnIndex ].length;
		for ( int i = startPosition; i < startPosition + nColumns; i++ ) {
			if ( i > startPosition ) {
				buf.append( ", " );
			}
			buf.append( i );
		}
		return buf.toString();
	}

	private String getColumnNamesString(int scalarColumnIndex) {
		return StringHelper.join( ", ", getWalker().getSelectClause().getColumnNames()[scalarColumnIndex] );
	}
}