/*
 * Microsoft JDBC Driver for SQL Server Copyright(c) Microsoft Corporation All rights reserved. This program is made
 * available under the terms of the MIT License. See the LICENSE file in the project root for more information.
 */

package com.microsoft.sqlserver.jdbc;

import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.naming.Reference;
import javax.sql.XAConnection;
import javax.sql.XADataSource;


Provides database connections for use in distributed (XA) transactions. SQLServerXADataSource also supports
connection pooling of physical connections.
The XADataSource and XAConnection interfaces, which are defined in the package javax.sql, are implemented by
sqlserver. An XAConnection object is a pooled connection that can participate in a distributed transaction. More
precisely, XAConnection extends the PooledConnection interface by adding the method getXAResource. This method
produces an XAResource object that can be used by a transaction manager to coordinate the work done on this
connection with the other participants in the distributed transaction.

Because they extend the PooledConnection interface, XAConnection objects support all the methods of PooledConnection
objects. They are reusable physical connections to an underlying data source and produce logical connection handles
that can be passed back to a JDBC application.

XAConnection objects are produced by an XADataSource object. There is some similarity between
ConnectionPoolDataSource objects and XADataSource objects in that they are both implemented below a DataSource layer
that is visible to the JDBC application. This architecture allows sqlserver to support distributed transactions in a
way that is transparent to the application.




SQLServerXADataSource can be configured to integrate with Microsoft Distributed Transaction Coordinator (DTC) to
provide true, distributed transaction processing.
/**
 * Provides database connections for use in distributed (XA) transactions. SQLServerXADataSource also supports
 * connection pooling of physical connections.
 *
 * The XADataSource and XAConnection interfaces, which are defined in the package javax.sql, are implemented by
 * sqlserver. An XAConnection object is a pooled connection that can participate in a distributed transaction. More
 * precisely, XAConnection extends the PooledConnection interface by adding the method getXAResource. This method
 * produces an XAResource object that can be used by a transaction manager to coordinate the work done on this
 * connection with the other participants in the distributed transaction.
 *
 * <p>
 * Because they extend the PooledConnection interface, XAConnection objects support all the methods of PooledConnection
 * objects. They are reusable physical connections to an underlying data source and produce logical connection handles
 * that can be passed back to a JDBC application.
 *
 * <p>
 * XAConnection objects are produced by an XADataSource object. There is some similarity between
 * ConnectionPoolDataSource objects and XADataSource objects in that they are both implemented below a DataSource layer
 * that is visible to the JDBC application. This architecture allows sqlserver to support distributed transactions in a
 * way that is transparent to the application.
 *
 * <br>
 * <br>
 * SQLServerXADataSource can be configured to integrate with Microsoft Distributed Transaction Coordinator (DTC) to
 * provide true, distributed transaction processing.
 */
public final class SQLServerXADataSource extends SQLServerConnectionPoolDataSource implements XADataSource {

    static Logger xaLogger = Logger.getLogger("com.microsoft.sqlserver.jdbc.internals.XA");

    
Returns a physical database connection to particate in an XA transaction with the specified user and password.
This API should only be called by XA connection pool implementations, not regular JDBC application code.
Throws:
SQLException – 
           The database connection failed.
Returns:
A new XAConnection/**
     * Returns a physical database connection to particate in an XA transaction with the specified user and password.
     * This API should only be called by XA connection pool implementations, not regular JDBC application code.
     *
     * @return A new XAConnection
     * @exception SQLException
     *            The database connection failed.
     */
    @Override
    public XAConnection getXAConnection(String user, String password) throws SQLException {
        if (loggerExternal.isLoggable(Level.FINER))
            loggerExternal.entering(getClassNameLogging(), "getXAConnection",
                    new Object[] {user, "Password not traced"});
        SQLServerXAConnection pooledXAConnection = new SQLServerXAConnection(this, user, password);

        if (xaLogger.isLoggable(Level.FINER))
            xaLogger.finer(toString() + " user:" + user + pooledXAConnection.toString());

        // Don't start a transaction here but do mark the connection as autocommit false.
        // We cannot start a transaction since XA transaction type 'NEVER' does not start a transaction
        // Autocommit of false is required to ensure that the transaction manager's calls to commit and
        // rollback work correctly.

        if (xaLogger.isLoggable(Level.FINER))
            xaLogger.finer(toString() + " Start get physical connection.");
        SQLServerConnection physicalConnection = pooledXAConnection.getPhysicalConnection();
        if (xaLogger.isLoggable(Level.FINE))
            xaLogger.fine(toString() + " End get physical connection, " + physicalConnection.toString());
        if (loggerExternal.isLoggable(Level.FINER))
            loggerExternal.exiting(getClassNameLogging(), "getXAConnection", pooledXAConnection);
        return pooledXAConnection;
    }

    
Returns a physical database connection to particate in an XA transaction. This API should only be called by XA
connection pool implementations, not regular JDBC application code.
Throws:
SQLException – 
           The database connection failed.
Returns:
A new XAConnection/**
     * Returns a physical database connection to particate in an XA transaction. This API should only be called by XA
     * connection pool implementations, not regular JDBC application code.
     *
     * @return A new XAConnection
     * @exception SQLException
     *            The database connection failed.
     */
    @Override
    public XAConnection getXAConnection() throws SQLException {
        if (loggerExternal.isLoggable(Level.FINER))
            loggerExternal.entering(getClassNameLogging(), "getXAConnection");
        return getXAConnection(getUser(), getPassword());
    }

    // Implement javax.naming.Referenceable interface methods.

    @Override
    public Reference getReference() {
        if (loggerExternal.isLoggable(Level.FINER))
            loggerExternal.entering(getClassNameLogging(), "getReference");
        Reference ref = getReferenceInternal("com.microsoft.sqlserver.jdbc.SQLServerXADataSource");
        if (loggerExternal.isLoggable(Level.FINER))
            loggerExternal.exiting(getClassNameLogging(), "getReference", ref);
        return ref;
    }

    private Object writeReplace() throws java.io.ObjectStreamException {
        return new SerializationProxy(this);
    }

    private void readObject(java.io.ObjectInputStream stream) throws java.io.InvalidObjectException {
        // For added security/robustness, the only way to rehydrate a serialized SQLServerXADataSource
        // is to use a SerializationProxy. Direct use of readObject() is not supported.
        throw new java.io.InvalidObjectException("");
    }

    
Implements java.io.Serializable the same way as SQLServerDataSource /**
     * Implements java.io.Serializable the same way as {@link SQLServerDataSource}
     */
    private static class SerializationProxy implements java.io.Serializable {
        private final Reference ref;
        private static final long serialVersionUID = 454661379842314126L;

        SerializationProxy(SQLServerXADataSource ds) {
            // We do not need the class name so pass null, serialization mechanism
            // stores the class info.
            ref = ds.getReferenceInternal(null);
        }

        private Object readResolve() {
            SQLServerXADataSource ds = new SQLServerXADataSource();
            ds.initializeFromReference(ref);
            return ds;
        }
    }
}