dbmonster-core-1.0.3.tar.gz

/* * Copyright 2004 Piotr Maj * * 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. */ package pl.kernelpanic.dbmonster.misc; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import pl.kernelpanic.dbmonster.DBMonster; import pl.kernelpanic.dbmonster.DBMonsterContext; import pl.kernelpanic.dbmonster.connection.ConnectionProvider; import pl.kernelpanic.dbmonster.connection.Transaction; import pl.kernelpanic.dbmonster.generator.Initializable; import pl.kernelpanic.dbmonster.generator.KeyGenerator; import pl.kernelpanic.dbmonster.schema.Column; import pl.kernelpanic.dbmonster.schema.Key; import pl.kernelpanic.dbmonster.schema.Table; /** * @author Piotr Maj <ant@kernelpanic.pl> * * $Revision: 1.1 $ $Date: 2004/06/11 10:37:59 $ */ public class CompositeKeyGenerator implements KeyGenerator, Initializable { private Key key; private DBMonsterContext context; private Column firstColumn; private Column secondColumn; private List columns; private ConnectionProvider connProvider; public void setKey(Key key) { this.key = key; } public List getColumns() { if (columns == null) { columns = new ArrayList(); columns.add(firstColumn); columns.add(secondColumn); } return columns; } public List generate() throws Exception { // first: be sure that table invoices is // already generated Table invTable = key.getTable().getSchema().findTable("invoices"); invTable.generate(); // Transaction is user-friendly wraper for pure JDBC obscure methods. Transaction tx = null; try { tx = new Transaction(connProvider); tx.begin(); //second: get the random invoice id from the invoices // table. ResultSet rs = tx.executeQuery("SELECT invno FROM invoices ORDER BY random() LIMIT 1"); rs.next(); int invno = rs.getInt("invno"); // this is our random invoice id // third: generate itemno using MAX + 1 strategy rs = tx.executeQuery("SELECT max(itemno) + 1 FROM invoice_items where invno = " + invno); int itemno = 1; if (rs.next()) { itemno = rs.getInt(1); } // we have all what we need so just set the column values firstColumn.setValue(new Integer(invno)); secondColumn.setValue(new Integer(itemno)); tx.commit(); } catch (Exception e) { throw e; } finally { tx.close(); } return getColumns(); } public void initialize(DBMonsterContext ctx) throws Exception { context = ctx; connProvider = (ConnectionProvider) context.getProperty(DBMonster.CONNECTION_PROVIDER_KEY); } public void setFirstColumn(String name) { firstColumn = new Column(); firstColumn.setName(name); firstColumn.reset(); } public String getFirstColumn() { if (firstColumn != null) { return firstColumn.getName(); } return null; } public void setSecondColumn(String name) { secondColumn = new Column(); secondColumn.setName(name); secondColumn.reset(); } public String getSecondColumn() { if (secondColumn != null) { return secondColumn.getName(); } return null; } }