jtatransactionmanager.java

spring 框架代码

	 * for every transaction. This is only necessary for application servers
	 * that return a new UserTransaction for every transaction, keeping state
	 * tied to the UserTransaction object itself rather than the current thread.
	 * @see #setUserTransactionName
	 */
	public void setCacheUserTransaction(boolean cacheUserTransaction) {
		this.cacheUserTransaction = cacheUserTransaction;
	}


	/**
	 * Set the JTA TransactionManager to use as direct reference.
	 * <p>A TransactionManager is necessary for suspending and resuming transactions,
	 * as this not supported by the UserTransaction interface.
	 * <p>Note that the TransactionManager will be autodetected if the JTA
	 * UserTransaction object implements the JTA TransactionManager interface too,
	 * as well as autodetected at various well-known fallback JNDI locations.
	 * @see #setTransactionManagerName
	 * @see #setAutodetectTransactionManager
	 */
	public void setTransactionManager(TransactionManager transactionManager) {
		this.transactionManager = transactionManager;
	}

	/**
	 * Return the JTA TransactionManager that this transaction manager uses.
	 */
	public TransactionManager getTransactionManager() {
		return this.transactionManager;
	}

	/**
	 * Set the JNDI name of the JTA TransactionManager.
	 * <p>A TransactionManager is necessary for suspending and resuming transactions,
	 * as this not supported by the UserTransaction interface.
	 * <p>Note that the TransactionManager will be autodetected if the JTA
	 * UserTransaction object implements the JTA TransactionManager interface too,
	 * as well as autodetected at various well-known fallback JNDI locations.
	 * @see #setTransactionManager
	 * @see #setAutodetectTransactionManager
	 */
	public void setTransactionManagerName(String transactionManagerName) {
		this.transactionManagerName = transactionManagerName;
	}

	/**
	 * Set whether to autodetect a JTA UserTransaction object that implements
	 * the JTA TransactionManager interface too (i.e. the JNDI location for the
	 * TransactionManager is "java:comp/UserTransaction", same as for the UserTransaction).
	 * Also checks the fallback JNDI locations "java:comp/TransactionManager" and
	 * "java:/TransactionManager". Will proceed without TransactionManager if none found.
	 * <p>Default is "true", autodetecting the TransactionManager unless it has been
	 * specified explicitly. Can be turned off to deliberately ignore an available
	 * TransactionManager, for example when there are known issues with suspend/resume
	 * and any attempt to use REQUIRES_NEW or NOT_SUPPORTED should fail fast.
	 * @see #FALLBACK_TRANSACTION_MANAGER_NAMES
	 */
	public void setAutodetectTransactionManager(boolean autodetectTransactionManager) {
		this.autodetectTransactionManager = autodetectTransactionManager;
	}


	public void afterPropertiesSet() throws TransactionSystemException {
		// Fetch JTA UserTransaction from JNDI, if necessary.
		if (this.userTransaction == null) {
			if (this.userTransactionName != null) {
				this.userTransaction = lookupUserTransaction(this.userTransactionName);
			}
			else {
				this.userTransaction = retrieveUserTransaction();
			}
		}

		// Fetch JTA TransactionManager from JNDI, if necessary.
		if (this.transactionManager == null) {
			if (this.transactionManagerName != null) {
				this.transactionManager = lookupTransactionManager(this.transactionManagerName);
			}
			else {
				this.transactionManager = retrieveTransactionManager();
			}
		}

		// Autodetect UserTransaction object that implements TransactionManager,
		// and check fallback JNDI locations else.
		if (this.transactionManager == null && this.autodetectTransactionManager) {
			this.transactionManager = findTransactionManager(this.userTransaction);
		}

		// If only JTA TransactionManager specified, create UserTransaction handle for it.
		if (this.userTransaction == null && this.transactionManager != null) {
			if (this.transactionManager instanceof UserTransaction) {
				this.userTransaction = (UserTransaction) this.transactionManager;
			}
			else {
				this.userTransaction = new UserTransactionAdapter(this.transactionManager);
			}
		}

		// We at least need the JTA UserTransaction.
		if (this.userTransaction != null) {
			if (logger.isInfoEnabled()) {
				logger.info("Using JTA UserTransaction: " + this.userTransaction);
			}
		}
		else {
			throw new IllegalArgumentException(
					"Either 'userTransaction' or 'userTransactionName' or 'transactionManager' " +
					"or 'transactionManagerName' must be specified");
		}

		// For transaction suspension, the JTA TransactionManager is necessary too.
		if (this.transactionManager != null) {
			if (logger.isInfoEnabled()) {
				logger.info("Using JTA TransactionManager: " + this.transactionManager);
			}
		}
		else {
			logger.warn("No JTA TransactionManager found: " +
					"transaction suspension and synchronization with existing JTA transactions not available");
		}
	}


	/**
	 * Look up the JTA UserTransaction in JNDI via the configured name.
	 * Called by <code>afterPropertiesSet</code> if no direct UserTransaction reference was set.
	 * Can be overridden in subclasses to provide a different UserTransaction object.
	 * @param userTransactionName the JNDI name of the UserTransaction
	 * @return the UserTransaction object
	 * @throws TransactionSystemException if the JNDI lookup failed
	 * @see #setJndiTemplate
	 * @see #setUserTransactionName
	 */
	protected UserTransaction lookupUserTransaction(String userTransactionName)
			throws TransactionSystemException {
		try {
			if (logger.isDebugEnabled()) {
				logger.debug("Retrieving JTA UserTransaction from JNDI location [" + userTransactionName + "]");
			}
			return (UserTransaction) getJndiTemplate().lookup(userTransactionName, UserTransaction.class);
		}
		catch (NamingException ex) {
			throw new TransactionSystemException(
					"JTA UserTransaction is not available at JNDI location [" + userTransactionName + "]", ex);
		}
	}

	/**
	 * Look up the JTA TransactionManager in JNDI via the configured name.
	 * Called by <code>afterPropertiesSet</code> if no direct TransactionManager reference was set.
	 * Can be overridden in subclasses to provide a different TransactionManager object.
	 * @param transactionManagerName the JNDI name of the TransactionManager
	 * @return the UserTransaction object
	 * @throws TransactionSystemException if the JNDI lookup failed
	 * @see #setJndiTemplate
	 * @see #setTransactionManagerName
	 */
	protected TransactionManager lookupTransactionManager(String transactionManagerName)
			throws TransactionSystemException {
		try {
			if (logger.isDebugEnabled()) {
				logger.debug("Retrieving JTA TransactionManager from JNDI location [" + transactionManagerName + "]");
			}
			return (TransactionManager) getJndiTemplate().lookup(transactionManagerName, TransactionManager.class);
		}
		catch (NamingException ex) {
			throw new TransactionSystemException(
					"JTA TransactionManager is not available at JNDI location [" + transactionManagerName + "]", ex);
		}
	}

	/**
	 * Allows subclasses to retrieve the JTA UserTransaction in a vendor-specific manner.
	 * Only called if no "userTransaction" or "userTransactionName" specified.
	 * <p>The default implementation simply returns <code>null</code>.
	 * @return the JTA UserTransaction handle to use, or <code>null</code> if none found
	 * @throws TransactionSystemException in case of errors
	 * @see #setUserTransaction
	 * @see #setUserTransactionName
	 */
	protected UserTransaction retrieveUserTransaction() throws TransactionSystemException {
		return null;
	}

	/**
	 * Allows subclasses to retrieve the JTA TransactionManager in a vendor-specific manner.
	 * Only called if no "transactionManager" or "transactionManagerName" specified.
	 * <p>The default implementation simply returns <code>null</code>.
	 * @return the JTA TransactionManager handle to use, or <code>null</code> if none found
	 * @throws TransactionSystemException in case of errors
	 * @see #setTransactionManager
	 * @see #setTransactionManagerName
	 */
	protected TransactionManager retrieveTransactionManager() throws TransactionSystemException {
		return null;
	}

	/**
	 * Find the JTA TransactionManager through autodetection:
	 * checking whether the UserTransaction object implements the
	 * TransactionManager, and checking the fallback JNDI locations.
	 * @param ut the JTA UserTransaction object
	 * @return the JTA TransactionManager reference, or <code>null</code> if not found
	 * @see #FALLBACK_TRANSACTION_MANAGER_NAMES
	 */
	protected TransactionManager findTransactionManager(UserTransaction ut) {
		if (ut instanceof TransactionManager) {
			if (logger.isDebugEnabled()) {
				logger.debug("JTA UserTransaction object [" + ut + "] implements TransactionManager");
			}
			return (TransactionManager) ut;
		}

		// Check fallback JNDI locations.
		for (int i = 0; i < FALLBACK_TRANSACTION_MANAGER_NAMES.length; i++) {
			String jndiName = FALLBACK_TRANSACTION_MANAGER_NAMES[i];
			try {
				TransactionManager tm = lookupTransactionManager(jndiName);
				if (logger.isDebugEnabled()) {
					logger.debug("JTA TransactionManager found at fallback JNDI location [" + jndiName + "]");
				}
				return tm;
			}
			catch (TransactionSystemException ex) {
				if (logger.isDebugEnabled()) {
					logger.debug("No JTA TransactionManager found at fallback JNDI location [" + jndiName + "]", ex);
				}
			}
		}

		// OK, so no JTA TransactionManager is available...
		return null;
	}


	/**
	 * This implementation returns a JtaTransactionObject instance for the
	 * JTA UserTransaction.
	 * <p>The UserTransaction object will either be looked up freshly for the
	 * current transaction, or the cached one looked up at startup will be used.
	 * The latter is the default: Most application servers use a shared singleton
	 * UserTransaction that can be cached. Turn off the "cacheUserTransaction"
	 * flag to enforce a fresh lookup for every transaction.
	 * @see #setCacheUserTransaction
	 */
	protected Object doGetTransaction() {
		UserTransaction ut = getUserTransaction();
		if (!this.cacheUserTransaction && this.userTransactionName != null) {
			ut = lookupUserTransaction(this.userTransactionName);
		}
		return doGetJtaTransaction(ut);
	}

	/**
	 * Get a JTA transaction object for the given current UserTransaction.
	 * <p>Subclasses can override this to provide a JtaTransactionObject
	 * subclass, for example holding some additional JTA handle needed.
	 * @param ut the UserTransaction handle to use for the current transaction
	 * @return the JtaTransactionObject holding the UserTransaction
	 */
	protected JtaTransactionObject doGetJtaTransaction(UserTransaction ut) {
		return new JtaTransactionObject(ut);
	}

	protected boolean isExistingTransaction(Object transaction) {
		JtaTransactionObject txObject = (JtaTransactionObject) transaction;
		try {
			return (txObject.getUserTransaction().getStatus() != Status.STATUS_NO_TRANSACTION);
		}
		catch (SystemException ex) {
			throw new TransactionSystemException("JTA failure on getStatus", ex);
		}
	}

	/**
	 * This implementation returns false to cause a further invocation
	 * of doBegin despite an already existing transaction.
	 * <p>JTA implementations might support nested transactions via further
	 * <code>UserTransaction.begin</code> invocations, but never support savepoints.
	 * @see #doBegin
	 * @see javax.transaction.UserTransaction#begin
	 */
	protected boolean useSavepointForNestedTransaction() {
		return false;
	}


	protected void doBegin(Object transaction, TransactionDefinition definition) {
		JtaTransactionObject txObject = (JtaTransactionObject) transaction;
		try {
			doJtaBegin(txObject, definition);
		}
		catch (NotSupportedException ex) {
			// assume nested transaction not supported
			throw new NestedTransactionNotSupportedException(
			    "JTA implementation does not support nested transactions", ex);
		}
		catch (UnsupportedOperationException ex) {
			// assume nested transaction not supported
			throw new NestedTransactionNotSupportedException(
			    "JTA implementation does not support nested transactions", ex);
		}
		catch (SystemException ex) {
			throw new CannotCreateTransactionException("JTA failure on begin", ex);
		}
	}