FileDocCategorySizeDatePackage
JdbcDataAdapter.javaAPI DocExample11121Sun Sep 02 14:59:04 BST 2001com.oreilly.forum.jdbcimpl

JdbcDataAdapter

public class JdbcDataAdapter extends DataAdapter
An implementation of the DataAdapter that uses JDBC.

Fields Summary
private String
dbURL
Constructors Summary
public JdbcDataAdapter()
Construct the data adapter and load the JDBC driver.

        this.dbURL = ForumConfig.getDatabaseURL();
        try {
            Class.forName(ForumConfig.getJDBCDriverClassName());
        } catch (Exception ex) {
            ex.printStackTrace();
            throw new DataException("Unable to load JDBC driver: "
                    + ForumConfig.getJDBCDriverClassName());
        }
Methods Summary
public java.util.IteratorgetAllBoards()

return
an iterator of all BoardSummary objects.

        List allBoards = new ArrayList();

        Connection con = null;
        Statement stmt = null;
        Statement stmt2 = null;
        try {
            con = DBUtil.getConnection(dbURL);
            stmt = con.createStatement();
            stmt2 = con.createStatement();
            ResultSet rs = stmt.executeQuery(
                    "SELECT id, name, description FROM Board "
                    + "ORDER BY name");

            while (rs.next()) {
                long id = rs.getLong(1);
                String name = rs.getString(2);
                String description = rs.getString(3);

                // get the months with messages. Use a different
                // Statement object because we are in the middle of
                // traversing a ResultSet that was created with the
                // first Statement.
                List monthsWithMessages =
                        this.getMonthsWithMessages(id, stmt2);

                allBoards.add(new BoardSummaryImpl(id, name, description,
                        monthsWithMessages));
            }
            return allBoards.iterator();
        } catch (SQLException sqe) {
            sqe.printStackTrace();
            throw new DataException(sqe);
        } finally {
            if (stmt2 != null) {
                try {
                    stmt2.close();
                } catch (SQLException ignored) {
                }
            }
            DBUtil.close(stmt, con);
        }
public java.util.IteratorgetAllMessages(long boardID, MonthYear month)
If no messages exist for the specified board and month, return an empty iterator.

return
an iterator of MessageSummary objects.
throws
DataException if the boardID is illegal or a database error occurs.

        List allMsgs = new ArrayList();

        Connection con = null;
        Statement stmt = null;
        try {
            con = DBUtil.getConnection(dbURL);
            stmt = con.createStatement();

            BoardSummary boardSum = this.getBoardSummary(boardID, stmt);

            ResultSet rs = stmt.executeQuery(
                    "SELECT id, inReplyToID, createDay, "
                    + "subject, authorEmail "
                    + "FROM Message WHERE createMonth="
                    + month.getMonth()
                    + " AND createYear="
                    + month.getYear()
                    + " AND boardID="
                    + boardID);

            while (rs.next()) {
                long msgID = rs.getLong(1);
                long inReplyTo = rs.getLong(2);
                int createDay = rs.getInt(3);
                String subject = rs.getString(4);
                String authorEmail = rs.getString(5);

                DayMonthYear createDMY = new DayMonthYear(
                        createDay, month.getMonth(), month.getYear());

                allMsgs.add(new MessageSummaryImpl(msgID, createDMY,
                        boardSum,
                        subject, authorEmail, inReplyTo));
            }
            return allMsgs.iterator();
        } catch (SQLException sqe) {
            sqe.printStackTrace();
            throw new DataException(sqe);
        } finally {
            DBUtil.close(stmt, con);
        }
public BoardSummarygetBoardSummary(long boardID)

return
a board summary for the given id.
throws
DataException if boardID is illegal or a database error occurs.

        Connection con = null;
        Statement stmt = null;
        try {
            con = DBUtil.getConnection(dbURL);
            stmt = con.createStatement();
            return getBoardSummary(boardID, stmt);
        } catch (SQLException sqe) {
            sqe.printStackTrace();
            throw new DataException(sqe);
        } finally {
            DBUtil.close(stmt, con);
        }
private BoardSummarygetBoardSummary(long boardID, java.sql.Statement stmt)

        ResultSet rs = stmt.executeQuery(
                "SELECT name, description FROM Board WHERE id=" + boardID);

        if (rs.next()) {
            String name = rs.getString(1);
            String description = rs.getString(2);

            List monthsWithMessages = getMonthsWithMessages(boardID, stmt);

            return new BoardSummaryImpl(boardID, name, description,
                    monthsWithMessages);
        } else {
            throw new DataException("Unknown boardID");
        }
public MessagegetMessage(long msgID)

param
msgID must be a valid message identifier.
return
the message with the specified id.
throws
DataException if msgID does not exist or a database error occurs.

        Connection con = null;
        Statement stmt = null;
        try {
            con = DBUtil.getConnection(dbURL);
            stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery(
                    "SELECT inReplyToID, createDay, createMonth, createYear, "
                    + "boardID, subject, authorEmail, msgText "
                    + "FROM Message WHERE id="
                    + msgID);
            if (rs.next()) {
                long inReplyToID = rs.getLong(1);
                int createDay = rs.getInt(2);
                int createMonth = rs.getInt(3);
                int createYear = rs.getInt(4);
                long boardID = rs.getLong(5);
                String subject = rs.getString(6);
                String authorEmail = rs.getString(7);
                String msgText = DBUtil.getLongString(rs, 8);

                BoardSummary boardSummary = this.getBoardSummary(boardID, stmt);

                return new MessageImpl(msgID,
                        new DayMonthYear(createDay, createMonth, createYear),
                        boardSummary, subject, authorEmail, msgText, 
                        inReplyToID);
            } else {
                throw new DataException("Illegal msgID: " + msgID);
            }
        } catch (SQLException sqe) {
            sqe.printStackTrace();
            throw new DataException(sqe.getMessage());
        } finally {
            DBUtil.close(stmt, con);
        }
private java.util.ListgetMonthsWithMessages(long boardID, java.sql.Statement stmt)

return
a list of MonthYear objects


        List monthsWithMessages = new ArrayList();
        ResultSet rs = stmt.executeQuery(
                "SELECT DISTINCT createMonth, createYear "
                + "FROM Message "
                + "WHERE boardID=" + boardID);
        while (rs.next()) {
            monthsWithMessages.add(new MonthYear(
                    rs.getInt(1), rs.getInt(2)));
        }
        return monthsWithMessages;
private MessageinsertMessage(BoardSummary board, long inReplyToID, java.lang.String msgSubject, java.lang.String authorEmail, java.lang.String msgText)

        // avoid overflowing the max database column lengths
        if (msgSubject.length() > ForumConfig.MAX_MSG_SUBJECT_LEN) {
            msgSubject = msgSubject.substring(0,
                    ForumConfig.MAX_MSG_SUBJECT_LEN);
        }
        if (authorEmail.length() > ForumConfig.MAX_EMAIL_LEN) {
            authorEmail = authorEmail.substring(0,
                    ForumConfig.MAX_EMAIL_LEN);
        }

        DayMonthYear createDate = new DayMonthYear();

        Connection con = null;
        PreparedStatement stmt = null;
        try {
            con = DBUtil.getConnection(dbURL);
            long newMsgID = DBUtil.getNextID("Message", con);
            stmt = con.prepareStatement("INSERT INTO Message "
                    + "(id, inReplyToID, createMonth, createDay, createYear, "
                    + "boardID, subject, authorEmail, msgText) "
                    + "VALUES (?,?,?,?,?,?,?,?,?)");
            stmt.setString(1, Long.toString(newMsgID));
            stmt.setString(2, Long.toString(inReplyToID));
            stmt.setInt(3, createDate.getMonth());
            stmt.setInt(4, createDate.getDay());
            stmt.setInt(5, createDate.getYear());
            stmt.setString(6, Long.toString(board.getID()));
            stmt.setString(7, msgSubject);
            stmt.setString(8, authorEmail);
            DBUtil.setLongString(stmt, 9, msgText);

            stmt.executeUpdate();

            return new MessageImpl(newMsgID, createDate,
                    board, msgSubject, authorEmail,
                    msgText, inReplyToID);

        } catch (SQLException sqe) {
            sqe.printStackTrace();
            throw new DataException(sqe);
        } finally {
            DBUtil.close(stmt, con);
        }
public MessagepostNewMessage(long boardID, java.lang.String msgSubject, java.lang.String authorEmail, java.lang.String msgText)
Post a new message.

return
the newly created message.
throws
DataException if a database error occurs, or if any parameter is illegal.


        BoardSummary board = this.getBoardSummary(boardID);
        return insertMessage(board, -1, msgSubject, authorEmail, msgText);
public MessagereplyToMessage(long origMsgID, java.lang.String msgSubject, java.lang.String authorEmail, java.lang.String msgText)
Add a reply to an existing message.

throws
DataException if a database error occurs, or if any parameter is illegal.

        Message inReplyToMsg = this.getMessage(origMsgID);
        return insertMessage(inReplyToMsg.getBoard(), origMsgID,
                msgSubject, authorEmail, msgText);