transferdb.java

hsql是很有名的嵌入式数据库

/* Copyright (c) 2001-2005, 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.util;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.Vector;

// fredt@users 20020215 - patch 516309 by Nicolas Bazin - enhancements
// sqlbob@users 20020401 - patch 1.7.0 - reengineering
// nicolas BAZIN 20020430 - add support of Catalog and mckoi db helper
// Stephan Frind 20040508 - speed improvements

/**
 * Conversions between different databases
 *
 * @version 1.7.0
 */
class TransferDb extends DataAccessPoint {

    Connection          conn;
    DatabaseMetaData    meta;
    protected Statement srcStatement = null;

    TransferDb(Connection c, Traceable t) throws DataAccessPointException {

        super(t);

        conn = c;

        if (c != null) {
            String productLowerName;

            try {
                meta              = c.getMetaData();
                databaseToConvert = c.getCatalog();
                productLowerName  = meta.getDatabaseProductName();

                if (productLowerName == null) {
                    productLowerName = "";
                } else {
                    productLowerName = productLowerName.toLowerCase();
                }

                helper = HelperFactory.getHelper(productLowerName);

                helper.set(this, t, meta.getIdentifierQuoteString());
            } catch (SQLException e) {
                throw new DataAccessPointException(e.getMessage());
            }
        }
    }

    boolean isConnected() {
        return (conn != null);
    }

    boolean getAutoCommit() throws DataAccessPointException {

        boolean result = false;

        try {
            result = conn.getAutoCommit();
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        }

        return result;
    }

    void commit() throws DataAccessPointException {

        if (srcStatement != null) {
            try {
                srcStatement.close();
            } catch (SQLException e) {}

            srcStatement = null;
        }

        try {
            conn.commit();
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        }
    }

    void rollback() throws DataAccessPointException {

        if (srcStatement != null) {
            try {
                srcStatement.close();
            } catch (SQLException e) {}

            srcStatement = null;
        }

        try {
            conn.rollback();
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        }
    }

    void setAutoCommit(boolean flag) throws DataAccessPointException {

        try {
            conn.setAutoCommit(flag);
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        }
    }

    boolean execute(String statement) throws DataAccessPointException {

        boolean   result = false;
        Statement stmt   = null;

        try {
            stmt   = conn.createStatement();
            result = stmt.execute(statement);
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        } finally {
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {}
            }
        }

        return result;
    }

    TransferResultSet getData(String statement)
    throws DataAccessPointException {

        ResultSet rsData = null;

        try {
            if (srcStatement != null) {
                srcStatement.close();
            }

            srcStatement = conn.createStatement();
            rsData       = srcStatement.executeQuery(statement);
        } catch (SQLException e) {
            try {
                srcStatement.close();
            } catch (Exception e1) {}

            srcStatement = null;
            rsData       = null;

            throw new DataAccessPointException(e.getMessage());
        }

        return new TransferResultSet(rsData);
    }

    void putData(String statement, TransferResultSet r,
                 int iMaxRows) throws DataAccessPointException {

        if ((statement == null) || statement.equals("") || (r == null)) {
            return;
        }

        PreparedStatement destPrep = null;

        try {
            destPrep = conn.prepareStatement(statement);

            int   i = 0;
            int   tmpLength;
            int   len      = r.getColumnCount();
            int[] tmpTypes = null;

            while (r.next()) {
                if (tmpTypes == null) {
                    tmpTypes = new int[len + 1];

                    for (int j = 1; j <= len; j++) {
                        tmpTypes[j] = r.getColumnType(j);
                    }
                }

                transferRow(r, destPrep, len, tmpTypes);

                if (iMaxRows != 0 && i == iMaxRows) {
                    break;
                }

                i++;

                if (iMaxRows != 0 || i % 100 == 0) {
                    tracer.trace("Transfered " + i + " rows");
                }
            }
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        } finally {
            if (destPrep != null) {
                try {
                    destPrep.close();
                } catch (SQLException e) {}
            }
        }
    }

/*
    private void transferRow(TransferResultSet r,
                             PreparedStatement p)
                             throws DataAccessPointException, SQLException {
        // TODO
        // what is this never used variable for?
        // looks like missing debug flags because constructing these strings consumes a lot
        // of time
        String sLast = "";

        if (p != null) {
            p.clearParameters();
        }

        int len = r.getColumnCount();

        for (int i = 0; i < len; i++) {
            int t = r.getColumnType(i + 1);

            sLast = "column=" + r.getColumnName(i + 1) + " datatype="
                    + (String) helper.getSupportedTypes().get(new Integer(t));

            Object o = r.getObject(i + 1);

            if (o == null) {
                if (p != null) {
                    p.setNull(i + 1, t);
                }

                sLast += " value=<null>";
            } else {
                o = helper.convertColumnValue(o, i + 1, t);

                p.setObject(i + 1, o);

                sLast += " value=\'" + o.toString() + "\'";
            }
        }

        if (p != null) {
            p.execute();
        }

        sLast = "";
    }
*/
    Vector getSchemas() throws DataAccessPointException {

        Vector    ret    = new Vector();
        ResultSet result = null;

        try {
            result = meta.getSchemas();
        } catch (SQLException e) {
            result = null;
        }

        try {
            if (result != null) {
                while (result.next()) {
                    ret.addElement(result.getString(1));
                }

                result.close();
            }
        } catch (SQLException e) {
            throw new DataAccessPointException(e.getMessage());
        }

        return (ret);
    }