/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * Licensed 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.wamblee.test.transactions;

import javax.transaction.HeuristicMixedException;
import javax.transaction.HeuristicRollbackException;
import javax.transaction.NotSupportedException;
import javax.transaction.RollbackException;
import javax.transaction.Status;
import javax.transaction.SystemException;
import javax.transaction.UserTransaction;

/**
 * Represents a user transaction spanning a number of resources.
 */
public class SimpleUserTransaction implements UserTransaction {

    private UserTransactionCallback callback;
    private TransactionResource[] resources;
    private Object[] txStates;
    private int status;

    /**
     * Construcst the transaction.
     * 
     * @param aCallback
     *            Callback to use.
     * @param aResources
     *            Resources to use.
     */
    public SimpleUserTransaction(UserTransactionCallback aCallback,
        TransactionResource<?>... aResources) {
        callback = aCallback;
        resources = aResources;
        txStates = new Object[resources.length];
        status = Status.STATUS_NO_TRANSACTION;
    }

    @Override
    public void begin() throws NotSupportedException, SystemException {
        if (status == Status.STATUS_ACTIVE) {
            throw new NotSupportedException(
                "Nested transactions not supported!");
        }
        for (int i = 0; i < resources.length; i++) {
            txStates[i] = resources[i].begin();
        }
        status = Status.STATUS_ACTIVE;
    }

    @Override
    public void rollback() throws IllegalStateException, SecurityException,
        SystemException {
        if ( status == Status.STATUS_NO_TRANSACTION) { 
            throw new IllegalStateException("Rollback while not in a transaction");
        }
        try {
            for (int i = 0; i < resources.length; i++) {
                resources[i].rollback(txStates[i]);
            }
        } finally {
            status = Status.STATUS_NO_TRANSACTION;
            callback.transactionFinished();
        }
    }

    @Override
    public void commit() throws RollbackException, HeuristicMixedException,
        HeuristicRollbackException, SecurityException, IllegalStateException,
        SystemException {
        if (status == Status.STATUS_MARKED_ROLLBACK) {
            rollback();
            throw new RollbackException();
        }
        if (status != Status.STATUS_ACTIVE) {
            throw new IllegalStateException("Commit while not in a transaction");
        }
        try {
            boolean committing = true;
            for (int i = 0; i < resources.length; i++) {
                try {
                    if (committing) {
                        resources[i].commit(txStates[i]);
                    } else {
                        resources[i].rollback(txStates[i]);
                    }
                } catch (Exception e) {
                    committing = false; 
                }
            }
            
            if (!committing) { 
                throw new HeuristicMixedException("Commit failed");
            }
        } finally {
            status = Status.STATUS_NO_TRANSACTION;
            callback.transactionFinished();
        }
    }

    @Override
    public int getStatus() throws SystemException {
        return status;
    }

    @Override
    public void setRollbackOnly() throws IllegalStateException, SystemException {
        if ( status == Status.STATUS_NO_TRANSACTION) { 
            throw new IllegalStateException("setRollbackOnly() while not in a transaction");
        }
        status = Status.STATUS_MARKED_ROLLBACK;
    }

    @Override
    public void setTransactionTimeout(int aSeconds) throws SystemException {
        // Ignored.
    }
}