dbconnectionmanager.java

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                        rs.next();
                    }
                }
            }
        }
        // Otherwise, manually scroll to the correct row.
        else {
            for (int i = 0; i < rowNumber; i++) {
                rs.next();
            }
        }
    }

    /**
     * Returns the current connection provider. The only case in which this
     * method should be called is if more information about the current
     * connection provider is needed. Database connections should always be
     * obtained by calling the getConnection method of this class.
     */
    public static ConnectionProvider getConnectionProvider() {
        return connectionProvider;
    }

    /**
     * Sets the connection provider. The old provider (if it exists) is shut
     * down before the new one is started. A connection provider <b>should
     * not</b> be started before being passed to the connection manager
     * because the manager will call the start() method automatically.
     *
     * @param provider the ConnectionProvider that the manager should obtain
     *                 connections from.
     */
    public static void setConnectionProvider(ConnectionProvider provider) {
        synchronized (providerLock) {
            if (connectionProvider != null) {
                connectionProvider.destroy();
                connectionProvider = null;
            }
            connectionProvider = provider;
            connectionProvider.start();
            // Now, get a connection to determine meta data.
            Connection con = null;
            try {
                con = connectionProvider.getConnection();
                setMetaData(con);

                // Check to see if the database schema needs to be upgraded.
                schemaManager.checkWildfireSchema(con);
            }
            catch (Exception e) {
                Log.error(e);
            }
            finally {
                try {
                    if (con != null) {
                        con.close();
                    }
                }
                catch (Exception e) {
                    Log.error(e);
                }
            }
        }
        // Remember what connection provider we want to use for restarts.
        JiveGlobals.setXMLProperty("connectionProvider.className", provider.getClass().getName());
    }

    /**
     * Destroys the currennt connection provider. Future calls to
     * {@link #getConnectionProvider()} will return <tt>null</tt> until a new
     * ConnectionProvider is set, or one is automatically loaded by a call to
     * {@link #getConnection()}.
     */
    public static void destroyConnectionProvider() {
        synchronized (providerLock) {
            if (connectionProvider != null) {
                connectionProvider.destroy();
                connectionProvider = null;
            }
        }
    }

    /**
     * Retrives a large text column from a result set, automatically performing
     * streaming if the JDBC driver requires it. This is necessary because
     * different JDBC drivers have different capabilities and methods for
     * retrieving large text values.
     *
     * @param rs          the ResultSet to retrieve the text field from.
     * @param columnIndex the column in the ResultSet of the text field.
     * @return the String value of the text field.
     */
    public static String getLargeTextField(ResultSet rs, int columnIndex) throws SQLException {
        if (isStreamTextRequired()) {
            Reader bodyReader = null;
            String value = null;
            try {
                bodyReader = rs.getCharacterStream(columnIndex);
                if (bodyReader == null) {
                    return null;
                }
                char[] buf = new char[256];
                int len;
                StringWriter out = new StringWriter(256);
                while ((len = bodyReader.read(buf)) >= 0) {
                    out.write(buf, 0, len);
                }
                value = out.toString();
                out.close();
            }
            catch (Exception e) {
                Log.error(e);
                throw new SQLException("Failed to load text field");
            }
            finally {
                try {
                    if (bodyReader != null) {
                        bodyReader.close();
                    }
                }
                catch (Exception e) {
                    // Ignore.
                }
            }
            return value;
        }
        else {
            return rs.getString(columnIndex);
        }
    }

    /**
     * Sets a large text column in a result set, automatically performing
     * streaming if the JDBC driver requires it. This is necessary because
     * different JDBC drivers have different capabilities and methods for
     * setting large text values.
     *
     * @param pstmt the PreparedStatement to set the text field in.
     * @param parameterIndex the index corresponding to the text field.
     * @param value the String to set.
     */
    public static void setLargeTextField(PreparedStatement pstmt, int parameterIndex,
                                         String value) throws SQLException {
        if (isStreamTextRequired()) {
            Reader bodyReader;
            try {
                bodyReader = new StringReader(value);
                pstmt.setCharacterStream(parameterIndex, bodyReader, value.length());
            }
            catch (Exception e) {
                Log.error(e);
                throw new SQLException("Failed to set text field.");
            }
            // Leave bodyReader open so that the db can read from it. It *should*
            // be garbage collected after it's done without needing to call close.
        }
        else {
            pstmt.setString(parameterIndex, value);
        }
    }

    /**
     * Sets the max number of rows that should be returned from executing a
     * statement. The operation is automatically bypassed if Jive knows that the
     * the JDBC driver or database doesn't support it.
     *
     * @param stmt    the Statement to set the max number of rows for.
     * @param maxRows the max number of rows to return.
     */
    public static void setMaxRows(Statement stmt, int maxRows) {
        if (isMaxRowsSupported()) {
            try {
                stmt.setMaxRows(maxRows);
            }
            catch (Throwable t) {
                // Ignore. Exception may happen if the driver doesn't support
                // this operation and we didn't set meta-data correctly.
                // However, it is a good idea to update the meta-data so that
                // we don't have to incur the cost of catching an exception
                // each time.
                maxRowsSupported = false;
            }
        }
    }

    /**
     * Sets the number of rows that the JDBC driver should buffer at a time.
     * The operation is automatically bypassed if Jive knows that the
     * the JDBC driver or database doesn't support it.
     *
     * @param rs the ResultSet to set the fetch size for.
     * @param fetchSize the fetchSize.
     */
    public static void setFetchSize(ResultSet rs, int fetchSize) {
        if (isFetchSizeSupported()) {
            try {
                rs.setFetchSize(fetchSize);
            }
            catch (Throwable t) {
                // Ignore. Exception may happen if the driver doesn't support
                // this operation and we didn't set meta-data correctly.
                // However, it is a good idea to update the meta-data so that
                // we don't have to incur the cost of catching an exception
                // each time.
                fetchSizeSupported = false;
            }
        }
    }

    /**
     * Returns a SchemaManager instance, which can be used to manage the database
     * schema information for Wildfire and plugins.
     *
     * @return a SchemaManager instance.
     */
    public static SchemaManager getSchemaManager() {
        return schemaManager;
    }

    /**
     * Uses a connection from the database to set meta data information about
     * what different JDBC drivers and databases support.
     */
    private static void setMetaData(Connection con) throws SQLException {
        DatabaseMetaData metaData = con.getMetaData();
        // Supports transactions?
        transactionsSupported = metaData.supportsTransactions();
        // Supports subqueries?
        subqueriesSupported = metaData.supportsCorrelatedSubqueries();
        // Supports scroll insensitive result sets? Try/catch block is a
        // workaround for DB2 JDBC driver, which throws an exception on
        // the method call.
        try {
            scrollResultsSupported = metaData.supportsResultSetType(
                    ResultSet.TYPE_SCROLL_INSENSITIVE);
        }
        catch (Exception e) {
            scrollResultsSupported = false;
        }
        // Supports batch updates
        batchUpdatesSupported = metaData.supportsBatchUpdates();

        // Set defaults for other meta properties
        streamTextRequired = false;
        maxRowsSupported = true;
        fetchSizeSupported = true;

        // Get the database name so that we can perform meta data settings.
        String dbName = metaData.getDatabaseProductName().toLowerCase();
        String driverName = metaData.getDriverName().toLowerCase();

        // Oracle properties.
        if (dbName.indexOf("oracle") != -1) {
            databaseType = DatabaseType.oracle;
            streamTextRequired = true;
            scrollResultsSupported = false;
            // The i-net AUGURO JDBC driver
            if (driverName.indexOf("auguro") != -1) {
                streamTextRequired = false;
                fetchSizeSupported = true;
                maxRowsSupported = false;
            }
        }
        // Postgres properties
        else if (dbName.indexOf("postgres") != -1) {
            databaseType = DatabaseType.postgresql;
            // Postgres blows, so disable scrolling result sets.
            scrollResultsSupported = false;
            fetchSizeSupported = false;
        }
        // Interbase properties
        else if (dbName.indexOf("interbase") != -1) {
            databaseType = DatabaseType.interbase;
            fetchSizeSupported = false;
            maxRowsSupported = false;
        }
        // SQLServer
        else if (dbName.indexOf("sql server") != -1) {
            databaseType = DatabaseType.sqlserver;
            // JDBC driver i-net UNA properties
            if (driverName.indexOf("una") != -1) {
                fetchSizeSupported = true;
                maxRowsSupported = false;
            }
        }
        // MySQL properties
        else if (dbName.indexOf("mysql") != -1) {
            databaseType = DatabaseType.mysql;
            transactionsSupported = false;
        }
        // HSQL properties
        else if (dbName.indexOf("hsql") != -1) {
            databaseType = DatabaseType.hsqldb;
            scrollResultsSupported = false;
        }
        // DB2 properties.
        else if (dbName.indexOf("db2") != 1) {
            databaseType = DatabaseType.db2;
        }
    }

    /**
     * Returns the database type. The possible types are constants of the
     * DatabaseType class. Any database that doesn't have its own constant
     * falls into the "Other" category.
     *
     * @return the database type.
     */
    public static DatabaseType getDatabaseType() {
        return databaseType;
    }

    /**
     * Returns true if connection profiling is turned on. You can collect
     * profiling statistics by using the static methods of the ProfiledConnection
     * class.
     *
     * @return true if connection profiling is enabled.
     */
    public static boolean isProfilingEnabled() {
        return profilingEnabled;
    }

    /**
     * Turns connection profiling on or off. You can collect profiling
     * statistics by using the static methods of the ProfiledConnection
     * class.
     *
     * @param enable true to enable profiling; false to disable.
     */
    public static void setProfilingEnabled(boolean enable) {
        // If enabling profiling, call the start method on ProfiledConnection
        if (!profilingEnabled && enable) {
            ProfiledConnection.start();
        }
        // Otherwise, if turning off, call stop method.
        else if (profilingEnabled && !enable) {
            ProfiledConnection.stop();
        }
        profilingEnabled = enable;
    }

    public static boolean isTransactionsSupported() {
        return transactionsSupported;
    }

    public static boolean isStreamTextRequired() {
        return streamTextRequired;
    }

    public static boolean isMaxRowsSupported() {
        return maxRowsSupported;
    }

    public static boolean isFetchSizeSupported() {

        return fetchSizeSupported;
    }

    public static boolean isSubqueriesSupported() {
        return subqueriesSupported;
    }

    public static boolean isScrollResultsSupported() {
        return scrollResultsSupported;
    }

    public static boolean isBatchUpdatesSupported() {
        return batchUpdatesSupported;
    }

    /**
     * A class that identifies the type of the database that Jive is connected
     * to. In most cases, we don't want to make any database specific calls
     * and have no need to know the type of database we're using. However,
     * there are certain cases where it's critical to know the database for
     * performance reasons.
     */
    public static enum DatabaseType {

        oracle,

        postgresql,

        mysql,

        hsqldb,

        db2,

        sqlserver,

        interbase,

        unknown
    }

    private DbConnectionManager() {
        // Not instantiable.
    }
}