Spring事物架构抽象及其默认实现
2017-11-09 15:15 deadMan_wyy 阅读(480) 评论(0) 编辑 收藏 举报Spring事物基本API:
1、org.springframework.transaction.PlatformTransactionManager是Spring事务抽象架构的核心接口,它的主要作用是为应用程序提供事务界定的统一方式。
public interface PlatformTransactionManager { /** * 获取事物 * @param definition * @return * @throws TransactionException */ TransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException; /** * 提交事物 * @param status * @throws TransactionException */ void commit(TransactionStatus status) throws TransactionException; /** * 回滚事物 * @param status * @throws TransactionException */ void rollback(TransactionStatus status) throws TransactionException; }
2、org.springframework.transaction.TransactionDefinition定义事务的隔离级别、传播行为、超时信息、只读信息
public interface TransactionDefinition { /** * Support a current transaction; create a new one if none exists. * Analogous to the EJB transaction attribute of the same name. * <p>This is typically the default setting of a transaction definition, * and typically defines a transaction synchronization scope. */ int PROPAGATION_REQUIRED = 0; /** * Support a current transaction; execute non-transactionally if none exists. * Analogous to the EJB transaction attribute of the same name. * <p><b>NOTE:</b> For transaction managers with transaction synchronization, * {@code PROPAGATION_SUPPORTS} is slightly different from no transaction * at all, as it defines a transaction scope that synchronization might apply to. * As a consequence, the same resources (a JDBC {@code Connection}, a * Hibernate {@code Session}, etc) will be shared for the entire specified * scope. Note that the exact behavior depends on the actual synchronization * configuration of the transaction manager! * <p>In general, use {@code PROPAGATION_SUPPORTS} with care! In particular, do * not rely on {@code PROPAGATION_REQUIRED} or {@code PROPAGATION_REQUIRES_NEW} * <i>within</i> a {@code PROPAGATION_SUPPORTS} scope (which may lead to * synchronization conflicts at runtime). If such nesting is unavoidable, make sure * to configure your transaction manager appropriately (typically switching to * "synchronization on actual transaction"). * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#setTransactionSynchronization * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#SYNCHRONIZATION_ON_ACTUAL_TRANSACTION */ int PROPAGATION_SUPPORTS = 1; /** * Support a current transaction; throw an exception if no current transaction * exists. Analogous to the EJB transaction attribute of the same name. * <p>Note that transaction synchronization within a {@code PROPAGATION_MANDATORY} * scope will always be driven by the surrounding transaction. */ int PROPAGATION_MANDATORY = 2; /** * Create a new transaction, suspending the current transaction if one exists. * Analogous to the EJB transaction attribute of the same name. * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box * on all transaction managers. This in particular applies to * {@link org.springframework.transaction.jta.JtaTransactionManager}, * which requires the {@code javax.transaction.TransactionManager} to be * made available it to it (which is server-specific in standard Java EE). * <p>A {@code PROPAGATION_REQUIRES_NEW} scope always defines its own * transaction synchronizations. Existing synchronizations will be suspended * and resumed appropriately. * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager */ int PROPAGATION_REQUIRES_NEW = 3; /** * Do not support a current transaction; rather always execute non-transactionally. * Analogous to the EJB transaction attribute of the same name. * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box * on all transaction managers. This in particular applies to * {@link org.springframework.transaction.jta.JtaTransactionManager}, * which requires the {@code javax.transaction.TransactionManager} to be * made available it to it (which is server-specific in standard Java EE). * <p>Note that transaction synchronization is <i>not</i> available within a * {@code PROPAGATION_NOT_SUPPORTED} scope. Existing synchronizations * will be suspended and resumed appropriately. * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager */ int PROPAGATION_NOT_SUPPORTED = 4; /** * Do not support a current transaction; throw an exception if a current transaction * exists. Analogous to the EJB transaction attribute of the same name. * <p>Note that transaction synchronization is <i>not</i> available within a * {@code PROPAGATION_NEVER} scope. */ int PROPAGATION_NEVER = 5; /** * Execute within a nested transaction if a current transaction exists, * behave like {@link #PROPAGATION_REQUIRED} else. There is no analogous * feature in EJB. * <p><b>NOTE:</b> Actual creation of a nested transaction will only work on * specific transaction managers. Out of the box, this only applies to the JDBC * {@link org.springframework.jdbc.datasource.DataSourceTransactionManager} * when working on a JDBC 3.0 driver. Some JTA providers might support * nested transactions as well. * @see org.springframework.jdbc.datasource.DataSourceTransactionManager */ int PROPAGATION_NESTED = 6; /** * Use the default isolation level of the underlying datastore. * All other levels correspond to the JDBC isolation levels. * @see java.sql.Connection */ int ISOLATION_DEFAULT = -1; /** * Indicates that dirty reads, non-repeatable reads and phantom reads * can occur. * <p>This level allows a row changed by one transaction to be read by another * transaction before any changes in that row have been committed (a "dirty read"). * If any of the changes are rolled back, the second transaction will have * retrieved an invalid row. * @see java.sql.Connection#TRANSACTION_READ_UNCOMMITTED */ int ISOLATION_READ_UNCOMMITTED = Connection.TRANSACTION_READ_UNCOMMITTED; /** * Indicates that dirty reads are prevented; non-repeatable reads and * phantom reads can occur. * <p>This level only prohibits a transaction from reading a row * with uncommitted changes in it. * @see java.sql.Connection#TRANSACTION_READ_COMMITTED */ int ISOLATION_READ_COMMITTED = Connection.TRANSACTION_READ_COMMITTED; /** * Indicates that dirty reads and non-repeatable reads are prevented; * phantom reads can occur. * <p>This level prohibits a transaction from reading a row with uncommitted changes * in it, and it also prohibits the situation where one transaction reads a row, * a second transaction alters the row, and the first transaction re-reads the row, * getting different values the second time (a "non-repeatable read"). * @see java.sql.Connection#TRANSACTION_REPEATABLE_READ */ int ISOLATION_REPEATABLE_READ = Connection.TRANSACTION_REPEATABLE_READ; /** * Indicates that dirty reads, non-repeatable reads and phantom reads * are prevented. * <p>This level includes the prohibitions in {@link #ISOLATION_REPEATABLE_READ} * and further prohibits the situation where one transaction reads all rows that * satisfy a {@code WHERE} condition, a second transaction inserts a row * that satisfies that {@code WHERE} condition, and the first transaction * re-reads for the same condition, retrieving the additional "phantom" row * in the second read. * @see java.sql.Connection#TRANSACTION_SERIALIZABLE */ int ISOLATION_SERIALIZABLE = Connection.TRANSACTION_SERIALIZABLE; /** * Use the default timeout of the underlying transaction system, * or none if timeouts are not supported. */ int TIMEOUT_DEFAULT = -1; /** * Return the propagation behavior. * <p>Must return one of the {@code PROPAGATION_XXX} constants * defined on {@link TransactionDefinition this interface}. * @return the propagation behavior * @see #PROPAGATION_REQUIRED * @see org.springframework.transaction.support.TransactionSynchronizationManager#isActualTransactionActive() */ int getPropagationBehavior(); /** * Return the isolation level. * <p>Must return one of the {@code ISOLATION_XXX} constants * defined on {@link TransactionDefinition this interface}. * <p>Only makes sense in combination with {@link #PROPAGATION_REQUIRED} * or {@link #PROPAGATION_REQUIRES_NEW}. * <p>Note that a transaction manager that does not support custom isolation levels * will throw an exception when given any other level than {@link #ISOLATION_DEFAULT}. * @return the isolation level */ int getIsolationLevel(); /** * Return the transaction timeout. * <p>Must return a number of seconds, or {@link #TIMEOUT_DEFAULT}. * <p>Only makes sense in combination with {@link #PROPAGATION_REQUIRED} * or {@link #PROPAGATION_REQUIRES_NEW}. * <p>Note that a transaction manager that does not support timeouts will throw * an exception when given any other timeout than {@link #TIMEOUT_DEFAULT}. * @return the transaction timeout */ int getTimeout(); /** * Return whether to optimize as a read-only transaction. * <p>The read-only flag applies to any transaction context, whether * backed by an actual resource transaction * ({@link #PROPAGATION_REQUIRED}/{@link #PROPAGATION_REQUIRES_NEW}) or * operating non-transactionally at the resource level * ({@link #PROPAGATION_SUPPORTS}). In the latter case, the flag will * only apply to managed resources within the application, such as a * Hibernate {@code Session}. * <p>This just serves as a hint for the actual transaction subsystem; * it will <i>not necessarily</i> cause failure of write access attempts. * A transaction manager which cannot interpret the read-only hint will * <i>not</i> throw an exception when asked for a read-only transaction. * @return {@code true} if the transaction is to be optimized as read-only * @see org.springframework.transaction.support.TransactionSynchronization#beforeCommit(boolean) * @see org.springframework.transaction.support.TransactionSynchronizationManager#isCurrentTransactionReadOnly() */ boolean isReadOnly(); /** * Return the name of this transaction. Can be {@code null}. * <p>This will be used as the transaction name to be shown in a * transaction monitor, if applicable (for example, WebLogic's). * <p>In case of Spring's declarative transactions, the exposed name will be * the {@code fully-qualified class name + "." + method name} (by default). * @return the name of this transaction * @see org.springframework.transaction.interceptor.TransactionAspectSupport * @see org.springframework.transaction.support.TransactionSynchronizationManager#getCurrentTransactionName() */ String getName(); }
3、org.springframework.transaction.TransactionStatus表示当前事物状态
public interface TransactionStatus extends SavepointManager, Flushable { /** * Return whether the present transaction is new (else participating * in an existing transaction, or potentially not running in an * actual transaction in the first place). */ boolean isNewTransaction(); /** * Return whether this transaction internally carries a savepoint, * that is, has been created as nested transaction based on a savepoint. * <p>This method is mainly here for diagnostic purposes, alongside * {@link #isNewTransaction()}. For programmatic handling of custom * savepoints, use SavepointManager's operations. * @see #isNewTransaction() * @see #createSavepoint * @see #rollbackToSavepoint(Object) * @see #releaseSavepoint(Object) */ boolean hasSavepoint(); /** * Set the transaction rollback-only. This instructs the transaction manager * that the only possible outcome of the transaction may be a rollback, as * alternative to throwing an exception which would in turn trigger a rollback. * <p>This is mainly intended for transactions managed by * {@link org.springframework.transaction.support.TransactionTemplate} or * {@link org.springframework.transaction.interceptor.TransactionInterceptor}, * where the actual commit/rollback decision is made by the container. * @see org.springframework.transaction.support.TransactionCallback#doInTransaction * @see org.springframework.transaction.interceptor.TransactionAttribute#rollbackOn */ void setRollbackOnly(); /** * Return whether the transaction has been marked as rollback-only * (either by the application or by the transaction infrastructure). */ boolean isRollbackOnly(); /** * Flush the underlying session to the datastore, if applicable: * for example, all affected Hibernate/JPA sessions. * <p>This is effectively just a hint and may be a no-op if the underlying * transaction manager does not have a flush concept. A flush signal may * get applied to the primary resource or to transaction synchronizations, * depending on the underlying resource. */ @Override void flush(); /** * Return whether this transaction is completed, that is, * whether it has already been committed or rolled back. * @see PlatformTransactionManager#commit * @see PlatformTransactionManager#rollback */ boolean isCompleted(); }