| // Copyright 2008 Google Inc. |
| // |
| // 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 com.google.gwtorm.jdbc; |
| |
| import com.google.gwtorm.client.OrmException; |
| import com.google.gwtorm.client.Schema; |
| import com.google.gwtorm.client.SchemaFactory; |
| import com.google.gwtorm.jdbc.gen.GeneratedClassLoader; |
| import com.google.gwtorm.jdbc.gen.SchemaFactoryGen; |
| import com.google.gwtorm.jdbc.gen.SchemaGen; |
| import com.google.gwtorm.schema.SchemaModel; |
| import com.google.gwtorm.schema.java.JavaSchemaModel; |
| import com.google.gwtorm.schema.sql.DialectH2; |
| import com.google.gwtorm.schema.sql.DialectPostgreSQL; |
| import com.google.gwtorm.schema.sql.SqlDialect; |
| |
| import java.sql.Connection; |
| import java.sql.DriverManager; |
| import java.sql.SQLException; |
| import java.util.Collections; |
| import java.util.Map; |
| import java.util.Properties; |
| import java.util.WeakHashMap; |
| |
| /** |
| * Constructor for application {@link Schema} extensions. |
| * <p> |
| * Applications should use the Database class to create instances of their |
| * Schema extension interface, and thus open and connect to the JDBC data store. |
| * <p> |
| * Creating a new Database instance is expensive, due to the type analysis and |
| * code generation performed to implement the Schema and Access interfaces. |
| * Applications should create and cache their Database instance for the live of |
| * the application. |
| * <p> |
| * Database instances are thread-safe, but returned Schema instances are not. |
| * |
| * @param <T> |
| */ |
| public class Database<T extends Schema> implements SchemaFactory<T> { |
| private static final Map<Class<?>, String> schemaFactoryNames = |
| Collections.synchronizedMap(new WeakHashMap<Class<?>, String>()); |
| |
| private final Properties connectionInfo; |
| private final String url; |
| private final JavaSchemaModel schemaModel; |
| private final AbstractSchemaFactory<T> implFactory; |
| private final SqlDialect implDialect; |
| |
| /** |
| * Create a new database interface, generating the interface implementations. |
| * <p> |
| * The JDBC properties information must define at least <code>url</code> and |
| * <code>driver</code>, but may also include driver specific properties such |
| * as <code>username</code> and <code>password</code>. |
| * |
| * @param dbInfo JDBC connection information. The property table is copied. |
| * @param schema application extension of the Schema interface to implement. |
| * @throws OrmException the schema interface is incorrectly defined, or the |
| * driver class is not available through the current class loader. |
| */ |
| public Database(final Properties dbInfo, final Class<T> schema) |
| throws OrmException { |
| connectionInfo = new Properties(); |
| connectionInfo.putAll(dbInfo); |
| |
| url = (String) connectionInfo.remove("url"); |
| if (url == null) { |
| throw new OrmException("Required property 'url' not defined"); |
| } |
| |
| final String driver = (String) connectionInfo.remove("driver"); |
| if (driver != null) { |
| loadDriver(driver); |
| } |
| |
| final SqlDialect dialect; |
| String dialectName = (String) connectionInfo.remove("dialect"); |
| if (dialectName != null) { |
| if (!dialectName.contains(".")) { |
| final String n = SqlDialect.class.getName(); |
| dialectName = n.substring(0, n.lastIndexOf('.') + 1) + dialectName; |
| } |
| try { |
| dialect = (SqlDialect) Class.forName(dialectName).newInstance(); |
| } catch (InstantiationException e) { |
| throw new OrmException("Dialect " + dialectName + " not available", e); |
| } catch (IllegalAccessException e) { |
| throw new OrmException("Dialect " + dialectName + " not available", e); |
| } catch (ClassNotFoundException e) { |
| throw new OrmException("Dialect " + dialectName + " not found", e); |
| } |
| } else if (url.startsWith("jdbc:postgresql:")) { |
| dialect = new DialectPostgreSQL(); |
| } else if (url.startsWith("jdbc:h2:")) { |
| dialect = new DialectH2(); |
| } else { |
| throw new OrmException("No dialect known for " + url); |
| } |
| |
| schemaModel = new JavaSchemaModel(schema); |
| final GeneratedClassLoader loader = newLoader(schema); |
| final String cachedName = schemaFactoryNames.get(schema); |
| AbstractSchemaFactory<T> factory = null; |
| if (cachedName != null) { |
| factory = newFactory(loader, cachedName); |
| } |
| if (factory == null) { |
| final SchemaGen gen = new SchemaGen(loader, schemaModel, dialect); |
| gen.defineClass(); |
| factory = new SchemaFactoryGen<T>(loader, gen).create(); |
| schemaFactoryNames.put(schema, factory.getClass().getName()); |
| } |
| implFactory = factory; |
| implDialect = dialect; |
| } |
| |
| @SuppressWarnings("unchecked") |
| private AbstractSchemaFactory<T> newFactory(final ClassLoader cl, |
| final String name) { |
| try { |
| final Class<?> ft = Class.forName(name, true, cl); |
| return (AbstractSchemaFactory<T>) ft.newInstance(); |
| } catch (InstantiationException e) { |
| return null; |
| } catch (IllegalAccessException e) { |
| return null; |
| } catch (ClassNotFoundException e) { |
| return null; |
| } |
| } |
| |
| SqlDialect getDialect() { |
| return implDialect; |
| } |
| |
| SchemaModel getSchemaModel() { |
| return schemaModel; |
| } |
| |
| /** |
| * Open a new connection to the database and get a Schema wrapper. |
| * |
| * @return a new JDBC connection, wrapped up in the application's Schema. |
| * @throws OrmException the connection could not be opened to the database. |
| * The JDBC exception detail should be examined to determine the root |
| * cause of the connection failure. |
| */ |
| public T open() throws OrmException { |
| final Connection conn; |
| try { |
| conn = DriverManager.getConnection(url, connectionInfo); |
| } catch (SQLException e) { |
| throw new OrmException("Cannot open database connection", e); |
| } |
| |
| try { |
| if (!conn.getAutoCommit()) { |
| conn.setAutoCommit(true); |
| } |
| } catch (SQLException e) { |
| try { |
| conn.close(); |
| } catch (SQLException e2) { |
| } |
| throw new OrmException("Cannot force auto-commit on connection", e); |
| } |
| |
| return implFactory.create(this, conn); |
| } |
| |
| private static <T> GeneratedClassLoader newLoader(final Class<T> schema) { |
| return new GeneratedClassLoader(schema.getClassLoader()); |
| } |
| |
| private static synchronized void loadDriver(final String driver) |
| throws OrmException { |
| // I've seen some drivers (*cough* Informix *cough*) which won't load |
| // on multiple threads at the same time. Forcing our code to synchronize |
| // around loading the driver ensures we won't ever ask for the same driver |
| // to initialize from different threads. Of course that could still happen |
| // in other parts of the same JVM, but its quite unlikely. |
| // |
| try { |
| Class.forName(driver, true, threadCL()); |
| } catch (ClassNotFoundException err) { |
| throw new OrmException("Driver class " + driver + " not available", err); |
| } |
| } |
| |
| private static ClassLoader threadCL() { |
| try { |
| return Thread.currentThread().getContextClassLoader(); |
| } catch (SecurityException e) { |
| return Database.class.getClassLoader(); |
| } |
| } |
| } |