it.eng.qbe.statement.hibernate.HQL2SQLStatementRewriter.java Source code

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Here is the source code for it.eng.qbe.statement.hibernate.HQL2SQLStatementRewriter.java

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/* SpagoBI, the Open Source Business Intelligence suite
    
 * Copyright (C) 2012 Engineering Ingegneria Informatica S.p.A. - SpagoBI Competency Center
 * This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0, without the "Incompatible With Secondary Licenses" notice. 
 * If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package it.eng.qbe.statement.hibernate;

import java.lang.reflect.Method;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.apache.log4j.Logger;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.hql.QueryTranslator;
import org.hibernate.hql.ast.ASTQueryTranslatorFactory;

/**
 * The Class HqlToSqlQueryRewriter.
 * 
 * @author Gioia
 */
public class HQL2SQLStatementRewriter {

    /** The session. */
    private Session session;

    /** Logger component. */
    public static transient Logger logger = Logger.getLogger(HQL2SQLStatementRewriter.class);

    /**
     * Instantiates a new hql to sql query rewriter.
     * 
     * @param session the session
     */
    public HQL2SQLStatementRewriter(Session session) {
        this.session = session;
    }

    /* (non-Javadoc)
     * @see it.eng.qbe.export.IQueryRewriter#rewrite(java.lang.String)
     */
    public String rewrite(String query) {
        String sqlQuery = null;
        logger.debug("rewrite: HQL query to convert: " + query);

        Query hibQuery = session.createQuery(query);
        SessionFactory sessionFactory = session.getSessionFactory();
        SessionFactoryImplementor sessionFactoryImplementor = (SessionFactoryImplementor) sessionFactory;
        ASTQueryTranslatorFactory astQueryTranslatorFactory = new ASTQueryTranslatorFactory();
        QueryTranslator queryTranslator = null;

        Class[] parsTypes = null;

        Method createQueryTranslatorMethod = null;
        try {
            // Hibernate 3.0
            parsTypes = new Class[3];
            parsTypes[0] = String.class;
            parsTypes[1] = Map.class;
            parsTypes[2] = SessionFactoryImplementor.class;

            createQueryTranslatorMethod = astQueryTranslatorFactory.getClass().getMethod("createQueryTranslator",
                    parsTypes);
            try {
                queryTranslator = (QueryTranslator) createQueryTranslatorMethod.invoke(astQueryTranslatorFactory,
                        new Object[] { hibQuery.getQueryString(), Collections.EMPTY_MAP,
                                sessionFactoryImplementor });
            } catch (Throwable e) {
                e.printStackTrace();
            }
        } catch (NoSuchMethodException e) {

            parsTypes = new Class[4];

            parsTypes[0] = String.class;
            parsTypes[1] = String.class;
            parsTypes[2] = Map.class;
            parsTypes[3] = SessionFactoryImplementor.class;

            try {
                createQueryTranslatorMethod = astQueryTranslatorFactory.getClass()
                        .getMethod("createQueryTranslator", parsTypes);

                if (createQueryTranslatorMethod != null) {
                    try {
                        queryTranslator = (QueryTranslator) createQueryTranslatorMethod.invoke(
                                astQueryTranslatorFactory,
                                new Object[] { String.valueOf(System.currentTimeMillis()),
                                        hibQuery.getQueryString(), Collections.EMPTY_MAP,
                                        sessionFactoryImplementor });
                    } catch (Throwable t) {
                        t.printStackTrace();
                    }
                }
            } catch (NoSuchMethodException ex) {
                e.printStackTrace();
            }
        }

        queryTranslator.compile(new HashMap(), false);
        sqlQuery = queryTranslator.getSQLString();

        logger.debug("rewrite: generated SQL query: " + sqlQuery);

        return sqlQuery;
    }

}