updatableresultset.java

开发MySql数据库的最新JDBC驱动。

	 * <p>
	 * Moves to the last row in the result set.
	 * </p>
	 * 
	 * @return true if on a valid row, false if no rows in the result set.
	 * 
	 * @exception SQLException
	 *                if a database-access error occurs, or result set type is
	 *                TYPE_FORWARD_ONLY.
	 */
	public synchronized boolean last() throws SQLException {
		return super.last();
	}

	/**
	 * JDBC 2.0 Move the cursor to the remembered cursor position, usually the
	 * current row. Has no effect unless the cursor is on the insert row.
	 * 
	 * @exception SQLException
	 *                if a database-access error occurs, or the result set is
	 *                not updatable
	 * @throws SQLException
	 *             if the ResultSet is not updatable or some other error occurs
	 */
	public synchronized void moveToCurrentRow() throws SQLException {
		checkClosed();

		if (!this.isUpdatable) {
			throw new NotUpdatable(this.notUpdatableReason);
		}

		if (this.onInsertRow) {
			this.onInsertRow = false;
			this.thisRow = this.savedCurrentRow;
		}
	}

	/**
	 * JDBC 2.0 Move to the insert row. The current cursor position is
	 * remembered while the cursor is positioned on the insert row. The insert
	 * row is a special row associated with an updatable result set. It is
	 * essentially a buffer where a new row may be constructed by calling the
	 * updateXXX() methods prior to inserting the row into the result set. Only
	 * the updateXXX(), getXXX(), and insertRow() methods may be called when the
	 * cursor is on the insert row. All of the columns in a result set must be
	 * given a value each time this method is called before calling insertRow().
	 * UpdateXXX()must be called before getXXX() on a column.
	 * 
	 * @exception SQLException
	 *                if a database-access error occurs, or the result set is
	 *                not updatable
	 * @throws NotUpdatable
	 *             DOCUMENT ME!
	 */
	public synchronized void moveToInsertRow() throws SQLException {
		checkClosed();

		if (!this.isUpdatable) {
			throw new NotUpdatable(this.notUpdatableReason);
		}

		if (this.inserter == null) {
			if (this.insertSQL == null) {
				generateStatements();
			}

			this.inserter = this.connection
					.clientPrepareStatement(this.insertSQL);
			if (this.populateInserterWithDefaultValues) {
				extractDefaultValues();
			}
			
			resetInserter();
		} else {
			resetInserter();
		}

		int numFields = this.fields.length;

		this.onInsertRow = true;
		this.doingUpdates = false;
		this.savedCurrentRow = this.thisRow;
		this.thisRow = new byte[numFields][];

		for (int i = 0; i < numFields; i++) {
			if (!this.populateInserterWithDefaultValues) {
				this.inserter.setBytesNoEscapeNoQuotes(i + 1, 
						"DEFAULT".getBytes());
				this.thisRow[i] = null;
			} else {
				if (this.defaultColumnValue[i] != null) {
					Field f = this.fields[i];
	
					switch (f.getMysqlType()) {
					case MysqlDefs.FIELD_TYPE_DATE:
					case MysqlDefs.FIELD_TYPE_DATETIME:
					case MysqlDefs.FIELD_TYPE_NEWDATE:
					case MysqlDefs.FIELD_TYPE_TIME:
					case MysqlDefs.FIELD_TYPE_TIMESTAMP:
	
						if (this.defaultColumnValue[i].length > 7
								&& this.defaultColumnValue[i][0] == (byte) 'C'
								&& this.defaultColumnValue[i][1] == (byte) 'U'
								&& this.defaultColumnValue[i][2] == (byte) 'R'
								&& this.defaultColumnValue[i][3] == (byte) 'R'
								&& this.defaultColumnValue[i][4] == (byte) 'E'
								&& this.defaultColumnValue[i][5] == (byte) 'N'
								&& this.defaultColumnValue[i][6] == (byte) 'T'
								&& this.defaultColumnValue[i][7] == (byte) '_') {
							this.inserter.setBytesNoEscapeNoQuotes(i + 1,
									this.defaultColumnValue[i]);
	
							break;
						}
					default:
						this.inserter.setBytes(i + 1, this.defaultColumnValue[i],
								false, false);
					}
	
					// This value _could_ be changed from a getBytes(), so we
					// need a copy....
					byte[] defaultValueCopy = new byte[this.defaultColumnValue[i].length];
					System.arraycopy(defaultColumnValue[i], 0, defaultValueCopy, 0,
							defaultValueCopy.length);
					this.thisRow[i] = defaultValueCopy;
				} else {
					this.inserter.setNull(i + 1, java.sql.Types.NULL);
					this.thisRow[i] = null;
				}
			}
		}
	}
	
	/**
	 * A ResultSet is initially positioned before its first row, the first call
	 * to next makes the first row the current row; the second call makes the
	 * second row the current row, etc.
	 * 
	 * <p>
	 * If an input stream from the previous row is open, it is implicitly
	 * closed. The ResultSet's warning chain is cleared when a new row is read
	 * </p>
	 * 
	 * @return true if the new current is valid; false if there are no more rows
	 * 
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public synchronized boolean next() throws SQLException {
		return super.next();
	}

	/**
	 * The prev method is not part of JDBC, but because of the architecture of
	 * this driver it is possible to move both forward and backward within the
	 * result set.
	 * 
	 * <p>
	 * If an input stream from the previous row is open, it is implicitly
	 * closed. The ResultSet's warning chain is cleared when a new row is read
	 * </p>
	 * 
	 * @return true if the new current is valid; false if there are no more rows
	 * 
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public synchronized boolean prev() throws SQLException {
		return super.prev();
	}

	/**
	 * JDBC 2.0
	 * 
	 * <p>
	 * Moves to the previous row in the result set.
	 * </p>
	 * 
	 * <p>
	 * Note: previous() is not the same as relative(-1) since it makes sense to
	 * call previous() when there is no current row.
	 * </p>
	 * 
	 * @return true if on a valid row, false if off the result set.
	 * 
	 * @exception SQLException
	 *                if a database-access error occurs, or result set type is
	 *                TYPE_FORWAR_DONLY.
	 */
	public synchronized boolean previous() throws SQLException {
		return super.previous();
	}

	/**
	 * Closes this ResultSet, releasing all resources.
	 * 
	 * @param calledExplicitly
	 *            was this called from close()?
	 * 
	 * @throws SQLException
	 *             if an error occurs.
	 */
	protected void realClose(boolean calledExplicitly) throws SQLException {
		if (this.isClosed) {
			return;
		}
		
		SQLException sqlEx = null;

		if (this.useUsageAdvisor) {
			if ((this.deleter == null) && (this.inserter == null)
					&& (this.refresher == null) && (this.updater == null)) {
				this.eventSink = ProfileEventSink.getInstance(this.connection);

				String message = Messages.getString("UpdatableResultSet.34"); //$NON-NLS-1$

				this.eventSink.consumeEvent(new ProfilerEvent(
						ProfilerEvent.TYPE_WARN,
						"", //$NON-NLS-1$
						(this.owningStatement == null) ? "N/A" //$NON-NLS-1$
								: this.owningStatement.currentCatalog, //$NON-NLS-1$
						this.connectionId,
						(this.owningStatement == null) ? (-1)
								: this.owningStatement.getId(), this.resultId,
						System.currentTimeMillis(), 0, Constants.MILLIS_I18N,
						null, this.pointOfOrigin, message));
			}
		}

		try {
			if (this.deleter != null) {
				this.deleter.close();
			}
		} catch (SQLException ex) {
			sqlEx = ex;
		}

		try {
			if (this.inserter != null) {
				this.inserter.close();
			}
		} catch (SQLException ex) {
			sqlEx = ex;
		}

		try {
			if (this.refresher != null) {
				this.refresher.close();
			}
		} catch (SQLException ex) {
			sqlEx = ex;
		}

		try {
			if (this.updater != null) {
				this.updater.close();
			}
		} catch (SQLException ex) {
			sqlEx = ex;
		}

		super.realClose(calledExplicitly);

		if (sqlEx != null) {
			throw sqlEx;
		}
	}

	/**
	 * JDBC 2.0 Refresh the value of the current row with its current value in
	 * the database. Cannot be called when on the insert row. The refreshRow()
	 * method provides a way for an application to explicitly tell the JDBC
	 * driver to refetch a row(s) from the database. An application may want to
	 * call refreshRow() when caching or prefetching is being done by the JDBC
	 * driver to fetch the latest value of a row from the database. The JDBC
	 * driver may actually refresh multiple rows at once if the fetch size is
	 * greater than one. All values are refetched subject to the transaction
	 * isolation level and cursor sensitivity. If refreshRow() is called after
	 * calling updateXXX(), but before calling updateRow() then the updates made
	 * to the row are lost. Calling refreshRow() frequently will likely slow
	 * performance.
	 * 
	 * @exception SQLException
	 *                if a database-access error occurs, or if called when on
	 *                the insert row.
	 * @throws NotUpdatable
	 *             DOCUMENT ME!
	 */
	public synchronized void refreshRow() throws SQLException {
		checkClosed();

		if (!this.isUpdatable) {
			throw new NotUpdatable();
		}

		if (this.onInsertRow) {
			throw SQLError.createSQLException(Messages.getString("UpdatableResultSet.8")); //$NON-NLS-1$
		} else if (this.rowData.size() == 0) {
			throw SQLError.createSQLException(Messages.getString("UpdatableResultSet.9")); //$NON-NLS-1$
		} else if (isBeforeFirst()) {
			throw SQLError.createSQLException(Messages.getString("UpdatableResultSet.10")); //$NON-NLS-1$
		} else if (isAfterLast()) {
			throw SQLError.createSQLException(Messages.getString("UpdatableResultSet.11")); //$NON-NLS-1$
		}

		refreshRow(this.updater, this.thisRow);
	}
	
	private synchronized void refreshRow(PreparedStatement updateInsertStmt, 
			Object[] rowToRefresh) throws SQLException {
		if (this.refresher == null) {
			if (this.refreshSQL == null) {
				generateStatements();
			}

			this.refresher = this.connection
					.clientPrepareStatement(this.refreshSQL);
		}

		this.refresher.clearParameters();

		int numKeys = this.primaryKeyIndicies.size();

		if (numKeys == 1) {
			byte[] dataFrom = null;
			int index = ((Integer) this.primaryKeyIndicies.get(0)).intValue();

			if (!this.doingUpdates && !this.onInsertRow) {
				dataFrom = (byte[]) rowToRefresh[index];
			} else {
				dataFrom = updateInsertStmt.getBytesRepresentation(index);

				// Primary keys not set?
				if (updateInsertStmt.isNull(index) || (dataFrom.length == 0)) {
					dataFrom = (byte[]) rowToRefresh[index];
				} else {
					dataFrom = stripBinaryPrefix(dataFrom);
				}
			}

			this.refresher.setBytesNoEscape(1, dataFrom);
		} else {
			for (int i = 0; i < numKeys; i++) {
				byte[] dataFrom = null;
				int index = ((Integer) this.primaryKeyIndicies.get(i))
						.intValue();

				if (!this.doingUpdates && !this.onInsertRow) {
					dataFrom = (byte[]) rowToRefresh[index];
				} else {
					dataFrom = updateInsertStmt.getBytesRepresentation(index);

					// Primary keys not set?
					if (updateInsertStmt.isNull(index) || (dataFrom.length == 0)) {
						dataFrom = (byte[]) this.thisRow[index];
					} else {
						dataFrom = stripBinaryPrefix(dataFrom);
					}
				}

				this.refresher.setBytesNoEscape(i + 1, dataFrom);
			}
		}

		java.sql.ResultSet rs = null;

		try {
			rs = this.refresher.executeQuery();

			int numCols = rs.getMetaData().getColumnCount();

			if (rs.next()) {
				for (int i = 0; i < numCols; i++) {
					byte[] val = rs.getBytes(i + 1);

					if ((val == null) || rs.wasNull()) {
						rowToRefresh[i] = null;
					} else {
						rowToRefresh[i] = rs.getBytes(i + 1);
					}
				}
			} else {
				throw SQLError.createSQLException(Messages
						.getString("UpdatableResultSet.12"), //$NON-NLS-1$
						SQLError.SQL_STATE_GENERAL_ERROR); //$NON-NLS-1$
			}
		} finally {
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException ex) {
					; // ignore
				}
			}
		}
	}

	/**
	 * JDBC 2.0
	 * 
	 * <p>
	 * Moves a relative number of rows, either positive or negative. Attempting
	 * to move beyond the first/last row in the result set positions the cursor
	 * before/after the the first/last row. Calling relative(0) is valid, but
	 * does not change the cursor position.
	 * </p>
	 * 
	 * <p>
	 * Note: Calling relative(1) is different than calling next() since is makes
	 * sense to call next() when there is no current row, for example, when the
	 * cursor is positioned before the first row or after the last row of the
	 * result set.
	 * </p>
	 * 
	 * @param rows
	 *            DOCUMENT ME!
	 * 
	 * @return true if on a row, false otherwise.
	 * 
	 * @exception SQLException
	 *                if a database-access error occurs, or there is no current
	 *                row, or result set type is TYPE_FORWARD_ONLY.
	 */
	public synchronized boolean relative(int rows) throws SQLException {
		return super.relative(rows);
	}

	private void resetInserter() throws SQLException {
		this.inserter.clearParameters();

		for (int i = 0; i < this.fields.length; i++) {
			this.inserter.setNull(i + 1, 0);
		}
	}

	/**
	 * JDBC 2.0 Determine if this row has been deleted. A deleted row may leave
	 * a visible "hole" in a result set. This method can be used to detect holes
	 * in a result set. The value returned depends on whether or not the result
	 * set can detect deletions.
	 * 
	 * @return true if deleted and deletes are detected