Hibernate example source code file (QueryNode.java)

This example Hibernate source code file (QueryNode.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

by, coremessagelogger, log, order, orderbyclause, orderbyclause, override, override, selectclause, selectexpression, semanticexception, semanticexception, string, string

The Hibernate QueryNode.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 org.hibernate.internal.CoreMessageLogger;
import org.hibernate.hql.internal.antlr.HqlSqlTokenTypes;
import org.hibernate.hql.internal.antlr.SqlTokenTypes;
import org.hibernate.hql.internal.ast.util.ASTUtil;
import org.hibernate.hql.internal.ast.util.ColumnHelper;
import org.hibernate.type.Type;
import org.jboss.logging.Logger;
import antlr.SemanticException;
import antlr.collections.AST;

/**
 * Defines a top-level AST node representing an HQL select statement.
 *
 * @author Joshua Davis
 */
public class QueryNode extends AbstractRestrictableStatement implements SelectExpression {

    private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, QueryNode.class.getName());

	private OrderByClause orderByClause;
	private int scalarColumnIndex = -1;

	/**
	 * @see Statement#getStatementType()
	 */
	public int getStatementType() {
		return HqlSqlTokenTypes.QUERY;
	}

	/**
	 * @see Statement#needsExecutor()
	 */
	public boolean needsExecutor() {
		return false;
	}

	@Override
    protected int getWhereClauseParentTokenType() {
		return SqlTokenTypes.FROM;
	}

	@Override
    protected CoreMessageLogger getLog() {
        return LOG;
	}

	/**
	 * Locate the select clause that is part of this select statement.
	 * </p>
	 * Note, that this might return null as derived select clauses (i.e., no
	 * select clause at the HQL-level) get generated much later than when we
	 * get created; thus it depends upon lifecycle.
	 *
	 * @return Our select clause, or null.
	 */
	public final SelectClause getSelectClause() {
		// Due to the complexity in initializing the SelectClause, do not generate one here.
		// If it is not found; simply return null...
		//
		// Also, do not cache since it gets generated well after we are created.
		return ( SelectClause ) ASTUtil.findTypeInChildren( this, SqlTokenTypes.SELECT_CLAUSE );
	}

	public final boolean hasOrderByClause() {
		OrderByClause orderByClause = locateOrderByClause();
		return orderByClause != null && orderByClause.getNumberOfChildren() > 0;
	}

	public final OrderByClause getOrderByClause() {
		if ( orderByClause == null ) {
			orderByClause = locateOrderByClause();

			// if there is no order by, make one
			if ( orderByClause == null ) {
                LOG.debugf("getOrderByClause() : Creating a new ORDER BY clause");
				orderByClause = ( OrderByClause ) ASTUtil.create( getWalker().getASTFactory(), SqlTokenTypes.ORDER, "ORDER" );

				// Find the WHERE; if there is no WHERE, find the FROM...
				AST prevSibling = ASTUtil.findTypeInChildren( this, SqlTokenTypes.WHERE );
				if ( prevSibling == null ) {
					prevSibling = ASTUtil.findTypeInChildren( this, SqlTokenTypes.FROM );
				}

				// Now, inject the newly built ORDER BY into the tree
				orderByClause.setNextSibling( prevSibling.getNextSibling() );
				prevSibling.setNextSibling( orderByClause );
			}
		}
		return orderByClause;
	}

	private OrderByClause locateOrderByClause() {
		return ( OrderByClause ) ASTUtil.findTypeInChildren( this, SqlTokenTypes.ORDER );
	}


	private String alias;

	public String getAlias() {
		return alias;
	}

	public FromElement getFromElement() {
		return null;
	}

	public boolean isConstructor() {
		return false;
	}

	public boolean isReturnableEntity() throws SemanticException {
		return false;
	}

	public boolean isScalar() throws SemanticException {
		return true;
	}

	public void setAlias(String alias) {
		this.alias = alias;
	}

	public void setScalarColumn(int i) throws SemanticException {
		scalarColumnIndex = i;
		setScalarColumnText( i );
	}

	public int getScalarColumnIndex() {
		return scalarColumnIndex;
	}

	public void setScalarColumnText(int i) throws SemanticException {
		ColumnHelper.generateSingleScalarColumn( this, i );
	}

	@Override
    public Type getDataType() {
		return ( (SelectExpression) getSelectClause().getFirstSelectExpression() ).getDataType();
	}

}