jdbcxydataset.java

来自「JfreeChart 常用图表例子」· Java 代码 · 共 577 行 · 第 1/2 页

            /// First column is X data
            this.columnNames = new String[numberOfValidColumns - 1];
            /// Get the column names and cache them.
            int currentColumn = 0;
            for (int column = 1; column < numberOfColumns; column++) {
                if (columnTypes[column] != Types.NULL) {
                    this.columnNames[currentColumn] 
                        = metaData.getColumnLabel(column + 1);
                    ++currentColumn;
                }
            }

            // Might need to add, to free memory from any previous result sets
            if (this.rows != null) {
                for (int column = 0; column < this.rows.size(); column++) {
                    ArrayList row = (ArrayList) this.rows.get(column);
                    row.clear();
                }
                this.rows.clear();
            }

            // Are we working with a time series.
            switch (columnTypes[0]) {
                case Types.DATE:
                case Types.TIME:
                case Types.TIMESTAMP:
                    this.isTimeSeries = true;
                    break;
                default :
                    this.isTimeSeries = false;
                    break;
            }

            // Get all rows.
            // rows = new ArrayList();
            while (resultSet.next()) {
                ArrayList newRow = new ArrayList();
                for (int column = 0; column < numberOfColumns; column++) {
                    Object xObject = resultSet.getObject(column + 1);
                    switch (columnTypes[column]) {
                        case Types.NUMERIC:
                        case Types.REAL:
                        case Types.INTEGER:
                        case Types.DOUBLE:
                        case Types.FLOAT:
                        case Types.DECIMAL:
                        case Types.BIGINT:
                        case Types.SMALLINT:
                            newRow.add(xObject);
                            break;

                        case Types.DATE:
                        case Types.TIME:
                        case Types.TIMESTAMP:
                            newRow.add(new Long(((Date) xObject).getTime()));
                            break;
                        case Types.NULL:
                            break;
                        default:
                            System.err.println("Unknown data");
                            columnTypes[column] = Types.NULL;
                            break;
                    }
                }
                this.rows.add(newRow);
            }

            /// a kludge to make everything work when no rows returned
            if (this.rows.size() == 0) {
                ArrayList newRow = new ArrayList();
                for (int column = 0; column < numberOfColumns; column++) {
                    if (columnTypes[column] != Types.NULL) {
                        newRow.add(new Integer(0));
                    }
                }
                this.rows.add(newRow);
            }

            /// Determine max and min values.
            if (this.rows.size() < 1) {
                this.maxValue = 0.0;
                this.minValue = 0.0;
            }
            else {
                ArrayList row = (ArrayList) this.rows.get(0);
                this.maxValue = Double.NEGATIVE_INFINITY;
                this.minValue = Double.POSITIVE_INFINITY;
                for (int rowNum = 0; rowNum < this.rows.size(); ++rowNum) {
                    row = (ArrayList) this.rows.get(rowNum);
                    for (int column = 1; column < numberOfColumns; column++) {
                        Object testValue = row.get(column);
                        if (testValue != null) {
                            double test = ((Number) testValue).doubleValue();
                        
                            if (test < this.minValue) {
                                this.minValue = test;
                            }
                            if (test > this.maxValue) {
                                this.maxValue = test;
                            }
                        }
                    }
                }
            }

            fireDatasetChanged(); // Tell the listeners a new table has arrived.
        }
        finally {
            if (resultSet != null) {
                try {
                    resultSet.close();
                }
                catch (Exception e) {
                    // TODO: is this a good idea?
                }
            }
            if (statement != null) {
                try {
                    statement.close();
                }
                catch (Exception e) {
                    // TODO: is this a good idea?
                }
            }
        }

    }

    /**
     * Returns the x-value for the specified series and item.  The
     * implementation is responsible for ensuring that the x-values are
     * presented in ascending order.
     *
     * @param  seriesIndex  the series (zero-based index).
     * @param  itemIndex  the item (zero-based index).
     *
     * @return The x-value
     *
     * @see XYDataset
     */
    public Number getX(int seriesIndex, int itemIndex) {
        ArrayList row = (ArrayList) this.rows.get(itemIndex);
        return (Number) row.get(0);
    }

    /**
     * Returns the y-value for the specified series and item.
     *
     * @param  seriesIndex  the series (zero-based index).
     * @param  itemIndex  the item (zero-based index).
     *
     * @return The yValue value
     *
     * @see XYDataset
     */
    public Number getY(int seriesIndex, int itemIndex) {
        ArrayList row = (ArrayList) this.rows.get(itemIndex);
        return (Number) row.get(seriesIndex + 1);
    }

    /**
     * Returns the number of items in the specified series.
     *
     * @param  seriesIndex  the series (zero-based index).
     *
     * @return The itemCount value
     *
     * @see XYDataset
     */
    public int getItemCount(int seriesIndex) {
        return this.rows.size();
    }

    /**
     * Returns the number of items in all series.  This method is defined by 
     * the {@link TableXYDataset} interface.
     * 
     * @return The item count.
     */
    public int getItemCount() {
        return getItemCount(0);
    }
    
    /**
     * Returns the number of series in the dataset.
     *
     * @return The seriesCount value
     *
     * @see XYDataset
     * @see Dataset
     */
    public int getSeriesCount() {
        return this.columnNames.length;
    }

    /**
     * Returns the key for the specified series.
     *
     * @param seriesIndex  the series (zero-based index).
     *
     * @return The seriesName value
     *
     * @see XYDataset
     * @see Dataset
     */
    public Comparable getSeriesKey(int seriesIndex) {

        if ((seriesIndex < this.columnNames.length) 
                && (this.columnNames[seriesIndex] != null)) {
            return this.columnNames[seriesIndex];
        }
        else {
            return "";
        }

    }

    /**
     * Returns the number of items that should be displayed in the legend.
     *
     * @return The legendItemCount value
     */
    public int getLegendItemCount() {
        return getSeriesCount();
    }

    /**
     * Returns the legend item labels.
     *
     * @return The legend item labels.
     */
    public String[] getLegendItemLabels() {
        return this.columnNames;
    }

    /**
     * Close the database connection
     */
    public void close() {

        try {
            this.connection.close();
        }
        catch (Exception e) {
            System.err.println("JdbcXYDataset: swallowing exception.");
        }

    }

    /**
     * Returns the minimum y-value in the dataset.
     *
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     * 
     * @return The minimum value.
     */
    public double getRangeLowerBound(boolean includeInterval) {
        return this.minValue;
    }
    
    /**
     * Returns the maximum y-value in the dataset.
     *
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     * 
     * @return The maximum value.
     */
    public double getRangeUpperBound(boolean includeInterval) {
        return this.maxValue;
    }

    /**
     * Returns the range of the values in this dataset's range.
     *
     * @param includeInterval  a flag that determines whether or not the
     *                         y-interval is taken into account.
     * 
     * @return The range.
     */
    public Range getRangeBounds(boolean includeInterval) {
        return new Range(this.minValue, this.maxValue);
    }

}