MentaBean

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/*
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * MentaBean => http://www.mentabean.org
 * Author: Sergio Oliveira Jr. (sergio.oliveira.jr@gmail.com)
 */

package org.mentabean.jdbc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import org.mentabean.BeanConfig;
import org.mentabean.BeanException;
import org.mentabean.BeanManager;
import org.mentabean.DBField;
import org.mentabean.util.Limit;
import org.mentabean.util.OrderBy;

/**
 * When using limit, Oracle will NOT sort first before limiting, so a trick must be used.
 *
 * Now in Oracle is 'sysdate'.
 *
 * Oracle only supports sequences for primary keys.
 *
 * @author soliveira
 *
 */

public class OracleBeanSession extends AnsiSQLBeanSession {

        public OracleBeanSession(final BeanManager beanManager, final Connection conn) {

                super(beanManager, conn);
        }

        @Override
        protected String getCurrentTimestampCommand() {

                return "sysdate";
        }

        /**
         * Oracle will not SORT first then apply LIMIT.
         */

        @Override
        protected StringBuilder handleLimit(final StringBuilder sb, final OrderBy orderBy, final Limit limit) {

                if (limit == null || limit.intValue() <= 0) {
                        return sb;
                }

                final StringBuilder sbLimit = new StringBuilder(sb.length() + 32);

                if (orderBy != null && !orderBy.isEmpty()) {

                        sbLimit.append("SELECT * FROM (").append(sb.toString()).append(") where rowcount <= ").append(limit);

                } else {

                        sbLimit.append(sb.toString()).append(" AND rownum <= ").append(limit);
                }

                return sbLimit;
        }

        @Override
        public void insert(final Object bean) {

                // find sequence field...

                final BeanConfig bc = beanManager.getBeanConfig(bean.getClass());

                if (bc == null) {
                        throw new BeanException("Cannot find bean config: " + bean.getClass());
                }

                final DBField seqField = bc.getSequenceField();

                if (seqField == null) {

                        super.insert(bean);
                       
                        dispatchAfterInsert(bean);

                        return;
                }

                PreparedStatement stmt = null;

                ResultSet rset = null;

                final StringBuilder sb = new StringBuilder(128);
               
                sb.append("select ");
               
                String seqName = bc.getSequenceName();
               
                if (seqName != null) {
                        // sequence name was defined defined
                        sb.append(seqName);
                } else {
                        // use the convention for sequence name
                        sb.append("seq_").append(seqField.getDbName()).append("_").append(bc.getTableName());  
                }

                sb.append(".nextval from ").append(bc.getTableName());

                try {

                        stmt = conn.prepareStatement(sb.toString());

                        rset = stmt.executeQuery();

                        if (rset.next()) {

                                final long id = rset.getLong(1);
                               
                                try {

                                        injectValue(bean, seqField.getName(), id, Integer.class);
                                       
                                } catch(Exception e) {
                                       
                                        // try long as well:
                                        injectValue(bean, seqField.getName(), id, Long.class);
                                }
                        }

                } catch (Exception e) {

                        throw new BeanException(e);

                } finally {

                        close(stmt, rset);
                }

                super.insert(bean);
               
                dispatchAfterInsert(bean);
        }

}