HSQLDB example source code file (TransactionManager.java)

This example HSQLDB source code file (TransactionManager.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

doubleintindex, hsqlarraylist, hsqlarraylist, hsqlexception, hsqlexception, integer, longkeyintvaluehashmap, object, row, row, session, transaction, transaction, transactionmanager

The HSQLDB TransactionManager.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb;

import org.hsqldb.lib.DoubleIntIndex;
import org.hsqldb.lib.HashMappedList;
import org.hsqldb.lib.HsqlArrayList;
import org.hsqldb.lib.LongKeyIntValueHashMap;

/**
 * Manages rows involved in transactions
 *
 * @author fredt@users
 * @version  1.8.0
 * @since 1.8.0
 */
public class TransactionManager {

    LongKeyIntValueHashMap rowSessionMap;
    boolean                reWriteProtect;
    Database               database;

    TransactionManager(Database db) {
        database      = db;
        rowSessionMap = new LongKeyIntValueHashMap(true);
    }

    public void setReWriteProtection(boolean value) {
        reWriteProtect = value;
    }

    void checkDelete(Session session, Row row) throws HsqlException {}

    void checkDelete(Session session,
                     HashMappedList rowSet) throws HsqlException {

        if (!reWriteProtect) {
            return;
        }

        int sessionid = session.getId();

        for (int i = 0, size = rowSet.size(); i < size; i++) {
            Row  row   = (Row) rowSet.getKey(i);
            long rowid = row.getId();

            if (rowSessionMap.get(rowid, sessionid) != sessionid) {
                throw Trace.error(Trace.INVALID_TRANSACTION_STATE_NO_SUBCLASS,
                                  Trace.ITSNS_OVERWRITE);
            }
        }
    }

    void checkDelete(Session session,
                     HsqlArrayList rowSet) throws HsqlException {

        if (!reWriteProtect) {
            return;
        }

        int sessionid = session.getId();

        for (int i = 0, size = rowSet.size(); i < size; i++) {
            Row  row   = (Row) rowSet.get(i);
            long rowid = row.getId();

            if (rowSessionMap.get(rowid, sessionid) != sessionid) {
                throw Trace.error(Trace.INVALID_TRANSACTION_STATE_NO_SUBCLASS,
                                  Trace.ITSNS_OVERWRITE);
            }
        }
    }

    void commit(Session session) {

        Object[] list = session.rowActionList.getArray();
        int      size = session.rowActionList.size();

        for (int i = 0; i < size; i++) {
            Transaction tx    = (Transaction) list[i];
            long        rowid = tx.row.getId();

            tx.commit(session);
            rowSessionMap.remove(rowid);
        }

        session.rowActionList.clear();
        session.savepoints.clear();
    }

    synchronized void rollback(Session session) {
        rollbackTransactions(session, 0, false);
        session.savepoints.clear();
    }

    void rollbackSavepoint(Session session,
                           String name) throws HsqlException {

        int index = session.savepoints.getIndex(name);

        if (index < 0) {
            throw Trace.error(Trace.SAVEPOINT_NOT_FOUND, name);
        }

        Integer oi    = (Integer) session.savepoints.get(index);
        int     limit = oi.intValue();

        rollbackTransactions(session, limit, false);

        while (session.savepoints.size() > index) {
            session.savepoints.remove(session.savepoints.size() - 1);
        }
    }

    void rollbackTransactions(Session session, int limit, boolean log) {

        Object[] list = session.rowActionList.getArray();
        int      size = session.rowActionList.size();

        for (int i = size - 1; i >= limit; i--) {
            Transaction tx = (Transaction) list[i];

            tx.rollback(session, log);
        }

        for (int i = limit; i < size; i++) {
            Transaction tx    = (Transaction) list[i];
            long        rowid = tx.row.getId();

            rowSessionMap.remove(rowid);
        }

        session.rowActionList.setSize(limit);
    }

    void addTransaction(Session session, Transaction transaction) {

        if (reWriteProtect) {
            rowSessionMap.put(transaction.row.getId(), session.getId());
        }
    }

    private long globalActionTimestamp = 0;

    /**
     * gets the next timestamp for an action
     */
    long nextActionTimestamp() {

        globalActionTimestamp++;

        return globalActionTimestamp;
    }

    /**
     * Return an array of all transactions sorted by System Change No.
     */
    Transaction[] getTransactionList() {

        Session[]     sessions = database.sessionManager.getAllSessions();
        int[]         tIndex   = new int[sessions.length];
        Transaction[] transactions;
        int           transactionCount = 0;

        {
            int actioncount = 0;

            for (int i = 0; i < sessions.length; i++) {
                actioncount += sessions[i].getTransactionSize();
            }

            transactions = new Transaction[actioncount];
        }

        while (true) {
            boolean found        = false;
            long    minChangeNo  = Long.MAX_VALUE;
            int     sessionIndex = 0;

            // find the lowest available SCN across all sessions
            for (int i = 0; i < sessions.length; i++) {
                int tSize = sessions[i].getTransactionSize();

                if (tIndex[i] < tSize) {
                    Transaction current =
                        (Transaction) sessions[i].rowActionList.get(
                            tIndex[i]);

                    if (current.SCN < minChangeNo) {
                        minChangeNo  = current.SCN;
                        sessionIndex = i;
                    }

                    found = true;
                }
            }

            if (!found) {
                break;
            }

            HsqlArrayList currentList = sessions[sessionIndex].rowActionList;

            for (; tIndex[sessionIndex] < currentList.size(); ) {
                Transaction current =
                    (Transaction) currentList.get(tIndex[sessionIndex]);

                // if the next change no is in this session, continue adding
                if (current.SCN == minChangeNo + 1) {
                    minChangeNo++;
                }

                if (current.SCN == minChangeNo) {
                    transactions[transactionCount++] = current;

                    tIndex[sessionIndex]++;
                } else {
                    break;
                }
            }
        }

        return transactions;
    }

    /**
     * Return a lookup of all transactions ids for cached tables.
     */
    public DoubleIntIndex getTransactionIDList() {

        Session[]      sessions = database.sessionManager.getAllSessions();
        DoubleIntIndex lookup   = new DoubleIntIndex(10, false);

        lookup.setKeysSearchTarget();

        for (int i = 0; i < sessions.length; i++) {
            HsqlArrayList tlist = sessions[i].rowActionList;

            for (int j = 0, size = tlist.size(); j < size; j++) {
                Transaction tx = (Transaction) tlist.get(j);

                if (tx.tTable.getTableType() == Table.CACHED_TABLE) {
                    lookup.addUnique(tx.row.getPos(), 0);
                }
            }
        }

        return lookup;
    }

    /**
     * Convert row ID's for cached table rows in transactions
     */
    public void convertTransactionIDs(DoubleIntIndex lookup) {

        Session[] sessions = database.sessionManager.getAllSessions();

        for (int i = 0; i < sessions.length; i++) {
            HsqlArrayList tlist = sessions[i].rowActionList;

            for (int j = 0, size = tlist.size(); j < size; j++) {
                Transaction tx = (Transaction) tlist.get(j);

                if (tx.tTable.getTableType() == Table.CACHED_TABLE) {
                    int pos = lookup.lookupFirstEqual(tx.row.getPos());

                    tx.row.setPos(pos);
                }
            }
        }
    }
}