package org.apache.torque.oid;/* * Copyright 2001-2004 The Apache Software Foundation. * * Licensed under the Apache License, Version 2.0 (the "License") * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *     http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */import java.math.BigDecimal;import java.sql.Connection;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.apache.torque.adapter.DB;import org.apache.torque.util.SQLBuilder;import com.workingdogs.village.QueryDataSet;import com.workingdogs.village.Record;import com.workingdogs.village.Value;/** * This generator works with databases that have an sql syntax for * getting an id prior to inserting a row into the database. * * @author <a href="mailto:jmcnally@collab.net">John D. McNally</a> * @version $Id: SequenceIdGenerator.java,v 1.12 2005/01/31 19:43:53 tfischer Exp $ */public class SequenceIdGenerator implements IdGenerator{    /** The log. */    private static Log log = LogFactory.getLog(SequenceIdGenerator.class);    /** the adapter that knows the correct sql syntax */    private DB dbAdapter;    /** The internal name of the Database that this Generator is connected to */    private String name = null;    /**     * Creates an IdGenerator which will work with the specified database.     *     * @param adapter the adapter that knows the correct sql syntax.     * @param name The name of the datasource to find the correct schema     */    public SequenceIdGenerator(final DB dbAdapter, final String name)    {        this.dbAdapter = dbAdapter;        this.name = name;    }    /**     * Retrieves an id as an int.     *     * @param connection A Connection.     * @param keyInfo an Object that contains additional info.     * @return An int with the value for the id.     * @exception Exception Database error.     */    public int getIdAsInt(Connection connection, Object keyInfo)        throws Exception    {        return getIdAsVillageValue(connection, keyInfo).asInt();    }    /**     * Retrieves an id as an long.     *     * @param connection A Connection.     * @param keyInfo an Object that contains additional info.     * @return A long with the value for the id.     * @exception Exception Database error.     */    public long getIdAsLong(Connection connection, Object keyInfo)        throws Exception    {        return getIdAsVillageValue(connection, keyInfo).asLong();    }    /**     * Retrieves an id as a BigDecimal.     *     * @param connection A Connection.     * @param keyInfo an Object that contains additional info.     * @return A BigDecimal id     * @exception Exception Database error.     */    public BigDecimal getIdAsBigDecimal(Connection connection, Object keyInfo)        throws Exception    {        return getIdAsVillageValue(connection, keyInfo).asBigDecimal();    }    /**     * Retrieves an id as an String.     *     * @param connection A Connection.     * @param keyInfo an Object that contains additional info.     * @return A String id     * @exception Exception Database error.     */    public String getIdAsString(Connection connection, Object keyInfo)        throws Exception    {        return getIdAsVillageValue(connection, keyInfo).asString();    }    /**     * A flag to determine the timing of the id generation     *     * @return a <code>boolean</code> value     */    public boolean isPriorToInsert()    {        return true;    }    /**     * A flag to determine the timing of the id generation     *     * @return a <code>boolean</code> value     */    public boolean isPostInsert()    {        return false;    }    /**     * A flag to determine whether a Connection is required to     * generate an id.     *     * @return a <code>boolean</code> value     */    public boolean isConnectionRequired()    {        return true;    }    /**     * Retrieves an id as a Village Value.     *     * @param connection A Connection.     * @param keyInfo an Object that contains additional info.     * @return A Village Value id.     * @exception Exception Database error.     */    private Value getIdAsVillageValue(Connection connection, Object keyInfo)        throws Exception    {        String sequenceName = SQLBuilder.getFullTableName(String.valueOf(keyInfo), name);        String idSql = dbAdapter.getIDMethodSQL(sequenceName);        if (log.isDebugEnabled())        {            log.debug(idSql);        }        // Execute the query.        QueryDataSet qds = new QueryDataSet(connection, idSql);        Record rec;        try        {            qds.fetchRecords(1);            rec = qds.getRecord(0);  // Records are 0 based.        }        finally        {            if (qds != null)            {                qds.close();            }        }        return rec.getValue(1); // Values are 1 based.    }}