sharding-jdbc中ShardingTransactionManager有什么用
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ShardingTransactionManager
incubator-shardingsphere-4.0.0-RC1/sharding-transaction/sharding-transaction-core/src/main/java/org/apache/shardingsphere/transaction/spi/ShardingTransactionManager.java
public interface ShardingTransactionManager extends AutoCloseable { /** * Initialize sharding transaction manager. * * @param databaseType database type * @param resourceDataSources resource data sources */ void init(DatabaseType databaseType, Collection resourceDataSources); /** * Get transaction type. * * @return transaction type */ TransactionType getTransactionType(); /** * Judge is in transaction or not. * * @return in transaction or not */ boolean isInTransaction(); /** * Get transactional connection. * * @param dataSourceName data source name * @return connection * @throws SQLException SQL exception */ Connection getConnection(String dataSourceName) throws SQLException; /** * Begin transaction. */ void begin(); /** * Commit transaction. */ void commit(); /** * Rollback transaction. */ void rollback();} ShardingTransactionManager继承了AutoCloseable接口，它定义了init、getTransactionType、isInTransaction、getConnection、begin、commit、rollback方法
XAShardingTransactionManager
incubator-shardingsphere-4.0.0-RC1/sharding-transaction/sharding-transaction-2pc/sharding-transaction-xa/sharding-transaction-xa-core/src/main/java/org/apache/shardingsphere/transaction/xa/XAShardingTransactionManager.java
public final class XAShardingTransactionManager implements ShardingTransactionManager { private final Map singleXADataSourceMap = new HashMap<>(); private final XATransactionManager xaTransactionManager = XATransactionManagerLoader.getInstance().getTransactionManager(); private ThreadLocal> enlistedXAResource = new ThreadLocal>() { @Override public List initialValue() { return new LinkedList<>(); } }; @Override public void init(final DatabaseType databaseType, final Collection resourceDataSources) { for (ResourceDataSource each : resourceDataSources) { DataSource dataSource = each.getDataSource(); if (dataSource instanceof AtomikosDataSourceBean) { continue; } SingleXADataSource singleXADataSource = new SingleXADataSource(databaseType, each.getUniqueResourceName(), dataSource); singleXADataSourceMap.put(each.getOriginalName(), singleXADataSource); xaTransactionManager.registerRecoveryResource(each.getUniqueResourceName(), singleXADataSource.getXaDataSource()); } xaTransactionManager.init(); } @Override public TransactionType getTransactionType() { return TransactionType.XA; } @SneakyThrows @Override public boolean isInTransaction() { return Status.STATUS_NO_TRANSACTION != xaTransactionManager.getTransactionManager().getStatus(); } @SneakyThrows @Override public Connection getConnection(final String dataSourceName) { SingleXAConnection singleXAConnection = singleXADataSourceMap.get(dataSourceName).getXAConnection(); if (!enlistedXAResource.get().contains(dataSourceName)) { xaTransactionManager.enlistResource(singleXAConnection.getXAResource()); enlistedXAResource.get().add(dataSourceName); } return singleXAConnection.getConnection(); } @SneakyThrows @Override public void begin() { xaTransactionManager.getTransactionManager().begin(); } @SneakyThrows @Override public void commit() { try { xaTransactionManager.getTransactionManager().commit(); } finally { enlistedXAResource.remove(); } } @SneakyThrows @Override public void rollback() { try { xaTransactionManager.getTransactionManager().rollback(); } finally { enlistedXAResource.remove(); } } @Override public void close() throws Exception { for (SingleXADataSource each : singleXADataSourceMap.values()) { xaTransactionManager.removeRecoveryResource(each.getResourceName(), each.getXaDataSource()); } singleXADataSourceMap.clear(); xaTransactionManager.close(); enlistedXAResource = null; }} XAShardingTransactionManager实现了ShardingTransactionManager接口，它拥有singleXADataSourceMap、xaTransactionManager、enlistedXAResource三个属性，其init方法对这三个属性进行了初始化
getTransactionType方法返回的是TransactionType.XA；isInTransaction方法则依据xaTransactionManager.getTransactionManager().getStatus()来判断；getConnection方法从singleXADataSourceMap取出singleXAConnection，然后执行其getConnection方法
begin方法执行的是xaTransactionManager.getTransactionManager().begin()；commit方法则调用了xaTransactionManager.getTransactionManager().commit()，其会在finally中执行enlistedXAResource.remove()；rollback方法调用了xaTransactionManager.getTransactionManager().rollback()，其也在finally中执行enlistedXAResource.remove()；close方法则执行xaTransactionManager.removeRecoveryResource、singleXADataSourceMap.clear()、xaTransactionManager.close()
XAShardingTransactionManagerTest
incubator-shardingsphere-4.0.0-RC1/sharding-transaction/sharding-transaction-2pc/sharding-transaction-xa/sharding-transaction-xa-core/src/test/java/org/apache/shardingsphere/transaction/xa/XAShardingTransactionManagerTest.java
@RunWith(MockitoJUnitRunner.class)public final class XAShardingTransactionManagerTest { private XAShardingTransactionManager xaShardingTransactionManager = new XAShardingTransactionManager(); @Mock private XATransactionManager xaTransactionManager; @Mock private TransactionManager transactionManager; @Before public void setUp() { when(xaTransactionManager.getTransactionManager()).thenReturn(transactionManager); ReflectiveUtil.setProperty(xaShardingTransactionManager, "xaTransactionManager", xaTransactionManager); } @Test public void assertGetTransactionType() { assertThat(xaShardingTransactionManager.getTransactionType(), is(TransactionType.XA)); } @Test public void assertRegisterXATransactionalDataSources() { Collection resourceDataSources = createResourceDataSources(DruidXADataSource.class, DatabaseType.MySQL); xaShardingTransactionManager.init(DatabaseType.MySQL, resourceDataSources); for (ResourceDataSource each : resourceDataSources) { verify(xaTransactionManager).registerRecoveryResource(each.getUniqueResourceName(), (XADataSource) each.getDataSource()); } } @Test public void assertRegisterAtomikosDataSourceBeans() { xaShardingTransactionManager.init(DatabaseType.MySQL, createAtomikosDataSourceBeanResource()); verify(xaTransactionManager, times(0)).registerRecoveryResource(anyString(), any(XADataSource.class)); } @Test public void assertRegisterNoneXATransactionalDAtaSources() { Collection resourceDataSources = createResourceDataSources(HikariDataSource.class, DatabaseType.MySQL); xaShardingTransactionManager.init(DatabaseType.MySQL, resourceDataSources); Map cachedXADatasourceMap = getCachedSingleXADataSourceMap(); assertThat(cachedXADatasourceMap.size(), is(2)); } @Test public void assertIsInTransaction() throws SystemException { when(transactionManager.getStatus()).thenReturn(Status.STATUS_ACTIVE); assertTrue(xaShardingTransactionManager.isInTransaction()); } @Test public void assertIsNotInTransaction() throws SystemException { when(transactionManager.getStatus()).thenReturn(Status.STATUS_NO_TRANSACTION); assertFalse(xaShardingTransactionManager.isInTransaction()); } @Test public void assertGetConnection() { setCachedSingleXADataSourceMap("ds1"); Connection actual = xaShardingTransactionManager.getConnection("ds1"); assertThat(actual, instanceOf(Connection.class)); verify(xaTransactionManager).enlistResource(any(SingleXAResource.class)); } @Test public void assertGetConnectionWithoutEnlist() { setCachedSingleXADataSourceMap("ds1"); Connection actual = xaShardingTransactionManager.getConnection("ds1"); assertThat(actual, instanceOf(Connection.class)); xaShardingTransactionManager.getConnection("ds1"); assertThat(actual, instanceOf(Connection.class)); verify(xaTransactionManager).enlistResource(any(SingleXAResource.class)); } @Test public void assertClose() throws Exception { setCachedSingleXADataSourceMap("ds1"); xaShardingTransactionManager.close(); Map cachedSingleXADataSourceMap = getCachedSingleXADataSourceMap(); verify(xaTransactionManager).removeRecoveryResource(anyString(), any(XADataSource.class)); assertThat(cachedSingleXADataSourceMap.size(), is(0)); } @SneakyThrows @SuppressWarnings("unchecked") private Map getCachedSingleXADataSourceMap() { Field field = xaShardingTransactionManager.getClass().getDeclaredField("singleXADataSourceMap"); field.setAccessible(true); return (Map) field.get(xaShardingTransactionManager); } @SneakyThrows private void setCachedSingleXADataSourceMap(final String datasourceName) { Field field = xaShardingTransactionManager.getClass().getDeclaredField("singleXADataSourceMap"); field.setAccessible(true); field.set(xaShardingTransactionManager, createMockSingleXADataSourceMap(datasourceName)); } @SneakyThrows private Map createMockSingleXADataSourceMap(final String datasourceName) { SingleXADataSource singleXADataSource = mock(SingleXADataSource.class); SingleXAConnection singleXAConnection = mock(SingleXAConnection.class); XADataSource xaDataSource = mock(XADataSource.class); SingleXAResource singleXAResource = mock(SingleXAResource.class); Connection connection = mock(Connection.class); when(singleXAConnection.getConnection()).thenReturn(connection); when(singleXAConnection.getXAResource()).thenReturn(singleXAResource); when(singleXADataSource.getXAConnection()).thenReturn(singleXAConnection); when(singleXADataSource.getResourceName()).thenReturn(datasourceName); when(singleXADataSource.getXaDataSource()).thenReturn(xaDataSource); Map result = new HashMap<>(); result.put(datasourceName, singleXADataSource); return result; } private Collection createResourceDataSources(final Class dataSourceClass, final DatabaseType databaseType) { List result = new LinkedList<>(); result.add(new ResourceDataSource("ds1", DataSourceUtils.build(dataSourceClass, databaseType, "demo_ds_1"))); result.add(new ResourceDataSource("ds2", DataSourceUtils.build(dataSourceClass, databaseType, "demo_ds_2"))); return result; } private Collection createAtomikosDataSourceBeanResource() { List result = new LinkedList<>(); result.add(new ResourceDataSource("ds1", new AtomikosDataSourceBean())); result.add(new ResourceDataSource("ds2", new AtomikosDataSourceBean())); return result; }} 这里mock了xaTransactionManager、transactionManager
小结
XAShardingTransactionManager实现了ShardingTransactionManager接口，它拥有singleXADataSourceMap、xaTransactionManager、enlistedXAResource三个属性，其init方法对这三个属性进行了初始化
getTransactionType方法返回的是TransactionType.XA；isInTransaction方法则依据xaTransactionManager.getTransactionManager().getStatus()来判断；getConnection方法从singleXADataSourceMap取出singleXAConnection，然后执行其getConnection方法
begin方法执行的是xaTransactionManager.getTransactionManager().begin()；commit方法则调用了xaTransactionManager.getTransactionManager().commit()，其会在finally中执行enlistedXAResource.remove()；rollback方法调用了xaTransactionManager.getTransactionManager().rollback()，其也在finally中执行enlistedXAResource.remove()；close方法则执行xaTransactionManager.removeRecoveryResource、singleXADataSourceMap.clear()、xaTransactionManager.close()
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