--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/java/sql-dk/src/main/java/info/globalcode/sql/dk/formatting/BarChartFormatter.java	Mon Mar 04 20:15:24 2019 +0100
@@ -0,0 +1,104 @@
+/**
+ * SQL-DK
+ * Copyright © 2015 František Kučera (frantovo.cz)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package info.globalcode.sql.dk.formatting;
+
+import info.globalcode.sql.dk.Functions;
+import info.globalcode.sql.dk.configuration.PropertyDeclaration;
+import info.globalcode.sql.dk.logging.LoggerProducer;
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.math.RoundingMode;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * TODO: min/max values – range for case that no value is 100 %
+ *
+ * TODO: multiple barcharts in same table (last column is still default) + multiple resultsets
+ *
+ * TODO: negative values - bar starting from the middle, not always from the left
+ *
+ * @author Ing. František Kučera (frantovo.cz)
+ */
+@PropertyDeclaration(name = BarChartFormatter.PROPERTY_PRECISION, type = Integer.class, defaultValue = BarChartFormatter.PROPERTY_PRECISION_DEFAULT, description = "number of characters representing 100 % in the bar chart")
+public class BarChartFormatter extends TabularPrefetchingFormatter {
+
+	public static final String NAME = "barchart"; // bash-completion:formatter
+	public static final String PROPERTY_PRECISION = "precision";
+	protected static final String PROPERTY_PRECISION_DEFAULT = "100";
+	private static final MathContext mathContext = MathContext.DECIMAL128;
+	public static final Logger log = LoggerProducer.getLogger();
+	private final BigDecimal chartPrecision;
+	private final char chartFull;
+	private final char chartEmpty;
+
+	public BarChartFormatter(FormatterContext formatterContext) {
+		super(formatterContext);
+		chartPrecision = BigDecimal.valueOf(formatterContext.getProperties().getInteger(PROPERTY_PRECISION, Integer.parseInt(PROPERTY_PRECISION_DEFAULT)));
+		chartFull = isAsciiNostalgia() ? '#' : '█';
+		chartEmpty = isAsciiNostalgia() ? '~' : '░';
+		// TODO: consider using partial blocks for more precision: https://en.wikipedia.org/wiki/Block_Elements
+	}
+
+	@Override
+	protected void postprocessPrefetchedResultSet(ColumnsHeader currentHeader, List<Object[]> currentResultSet) {
+		super.postprocessPrefetchedResultSet(currentHeader, currentResultSet);
+
+		updateColumnWidth(currentHeader.getColumnCount(), chartPrecision.intValue());
+
+		BigDecimal maximum = BigDecimal.ZERO;
+		BigDecimal minimum = BigDecimal.ZERO;
+		int lastIndex = currentHeader.getColumnCount() - 1;
+
+		Object valueObject = null;
+		try {
+			for (Object[] row : currentResultSet) {
+				valueObject = row[lastIndex];
+				if (valueObject != null) {
+					BigDecimal value = new BigDecimal(valueObject.toString());
+					maximum = maximum.max(value);
+					minimum = minimum.min(value);
+				}
+			}
+
+			BigDecimal range = maximum.subtract(minimum);
+
+			for (Object[] row : currentResultSet) {
+				valueObject = row[lastIndex];
+				if (valueObject == null) {
+					row[lastIndex] = "";
+				} else {
+					BigDecimal value = new BigDecimal(valueObject.toString());
+					BigDecimal valueFromMinimum = value.subtract(minimum);
+
+					BigDecimal points = chartPrecision.divide(range, mathContext).multiply(valueFromMinimum, mathContext);
+					int pointsRounded = points.setScale(0, RoundingMode.HALF_UP).intValue();
+					row[lastIndex] = Functions.repeat(chartFull, pointsRounded) + Functions.repeat(chartEmpty, chartPrecision.intValue() - pointsRounded);
+				}
+			}
+
+		} catch (NumberFormatException e) {
+			// https://en.wiktionary.org/wiki/parsable
+			log.log(Level.SEVERE, "Last column must be number or an object with toString() value parsable to a number. But was „{0}“", valueObject);
+			// FIXME: throw FormatterException
+			throw e;
+		}
+	}
+
+}