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contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You 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.
/**
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.dbcp.managed;

import javax.transaction.RollbackException;
import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.SystemException;
import javax.transaction.Transaction;
import javax.transaction.xa.XAResource;
import java.sql.Connection;
import java.sql.SQLException;
import java.lang.ref.WeakReference;

TransactionContext represents the association between a single XAConnectionFactory and a Transaction.
This context contains a single shared connection which should be used by all ManagedConnections for
the XAConnectionFactory, the ability to listen for the transaction completion event, and a method
to check the status of the transaction.
Author:
Dain Sundstrom
Version:
$Revision$/**
 * TransactionContext represents the association between a single XAConnectionFactory and a Transaction.
 * This context contains a single shared connection which should be used by all ManagedConnections for
 * the XAConnectionFactory, the ability to listen for the transaction completion event, and a method
 * to check the status of the transaction.
 *
 * @author Dain Sundstrom
 * @version $Revision$
 */
public class TransactionContext {
    private final TransactionRegistry transactionRegistry;
    private final WeakReference transactionRef;
    private Connection sharedConnection;

    
Creates a TransactionContext for the specified Transaction and TransactionRegistry.  The
TransactionRegistry is used to obtain the XAResource for the shared connection when it is
enlisted in the transaction.
Params:
transactionRegistry – the TransactionRegistry used to obtain the XAResource for the
shared connection
transaction – the transaction/**
     * Creates a TransactionContext for the specified Transaction and TransactionRegistry.  The
     * TransactionRegistry is used to obtain the XAResource for the shared connection when it is
     * enlisted in the transaction.
     *
     * @param transactionRegistry the TransactionRegistry used to obtain the XAResource for the
     * shared connection
     * @param transaction the transaction
     */
    public TransactionContext(TransactionRegistry transactionRegistry, Transaction transaction) {
        if (transactionRegistry == null) throw new NullPointerException("transactionRegistry is null");
        if (transaction == null) throw new NullPointerException("transaction is null");
        this.transactionRegistry = transactionRegistry;
        this.transactionRef = new WeakReference(transaction);
    }

    
Gets the connection shared by all ManagedConnections in the transaction.  Specifically,
connection using the same XAConnectionFactory from which the TransactionRegistry was
obtained.
Returns:
the shared connection for this transaction/**
     * Gets the connection shared by all ManagedConnections in the transaction.  Specifically,
     * connection using the same XAConnectionFactory from which the TransactionRegistry was
     * obtained.
     * @return the shared connection for this transaction
     */
    public Connection getSharedConnection() {
        return sharedConnection;
    }

    
Sets the shared connection for this transaction.  The shared connection is enlisted
in the transaction.
Params:
sharedConnection – the shared connection
Throws:
SQLException – if a shared connection is already set, if XAResource for the connection
could not be found in the transaction registry, or if there was a problem enlisting the
connection in the transaction/**
     * Sets the shared connection for this transaction.  The shared connection is enlisted
     * in the transaction.
     *
     * @param sharedConnection the shared connection
     * @throws SQLException if a shared connection is already set, if XAResource for the connection
     * could not be found in the transaction registry, or if there was a problem enlisting the
     * connection in the transaction
     */
    public void setSharedConnection(Connection sharedConnection) throws SQLException {
        if (this.sharedConnection != null) {
            throw new IllegalStateException("A shared connection is alredy set");
        }

        // This is the first use of the connection in this transaction, so we must
        // enlist it in the transaction
        Transaction transaction = getTransaction();
        try {
            XAResource xaResource = transactionRegistry.getXAResource(sharedConnection);
            transaction.enlistResource(xaResource);
        } catch (RollbackException e) {
            // transaction was rolled back... proceed as if there never was a transaction
        } catch (SystemException e) {
            throw (SQLException) new SQLException("Unable to enlist connection the transaction").initCause(e);
        }

        this.sharedConnection = sharedConnection;
    }

    
Adds a listener for transaction completion events.
Params:
listener – the listener to add
Throws:
SQLException – if a problem occurs adding the listener to the transaction/**
     * Adds a listener for transaction completion events.
     *
     * @param listener the listener to add
     * @throws SQLException if a problem occurs adding the listener to the transaction
     */
    public void addTransactionContextListener(final TransactionContextListener listener) throws SQLException {
        try {
            getTransaction().registerSynchronization(new Synchronization() {
                public void beforeCompletion() {
                }

                public void afterCompletion(int status) {
                    listener.afterCompletion(TransactionContext.this, status == Status.STATUS_COMMITTED);
                }
            });
        } catch (RollbackException e) {
            // JTA spec doesn't let us register with a transaction marked rollback only
            // just ignore this and the tx state will be cleared another way.
        } catch (Exception e) {
            throw (SQLException) new SQLException("Unable to register transaction context listener").initCause(e);
        }
    }

    
True if the transaction is active or marked for rollback only.
Throws:
SQLException – if a problem occurs obtaining the transaction status
Returns:
true if the transaction is active or marked for rollback only; false otherwise/**
     * True if the transaction is active or marked for rollback only.
     * @return true if the transaction is active or marked for rollback only; false otherwise
     * @throws SQLException if a problem occurs obtaining the transaction status
     */
    public boolean isActive() throws SQLException {
        try {
            Transaction transaction = (Transaction) this.transactionRef.get();
            if (transaction == null) {
                return false;
            }
            int status = transaction.getStatus();
            return status == Status.STATUS_ACTIVE || status == Status.STATUS_MARKED_ROLLBACK;
        } catch (SystemException e) {
            throw (SQLException) new SQLException("Unable to get transaction status").initCause(e);
        }
    }

    private Transaction getTransaction() throws SQLException {
        Transaction transaction = (Transaction) this.transactionRef.get();
        if (transaction == null) {
            throw new SQLException("Unable to enlist connection because the transaction has been garbage collected");
        }
        return transaction;
    }
}