add logarithmic scaling for the y-axis

Often we have a few very high values and a lot
low values. With a linearly scaled y-axis the
plot is mostly useless.

pdb-ui/src/main/java/org/lucares/pdbui/PlotSettingsTransformer.java

@@ -1,9 +1,11 @@
 package org.lucares.pdbui;
 
+import org.lucares.pdb.plot.api.AxisScale;
 import org.lucares.pdb.plot.api.Limit;
 import org.lucares.pdb.plot.api.PlotSettings;
 import org.lucares.pdbui.domain.LimitBy;
 import org.lucares.pdbui.domain.PlotRequest;
+import org.lucares.pdbui.domain.YAxis;
 
 class PlotSettingsTransformer {
 	static PlotSettings toSettings(final PlotRequest request) {
@@ -18,10 +20,24 @@ class PlotSettingsTransformer {
 		result.setLimitBy(toLimit(request.getLimitBy()));
 		result.setDateFrom(request.getDateFrom());
 		result.setDateRange(request.getDateRange());
+		result.setYAxisScale(toAxisScale(request.getAxisScale()));
 
 		return result;
 	}
 
+	private static AxisScale toAxisScale(final YAxis yAxis) {
+		switch (yAxis) {
+		case LINEAR:
+			return AxisScale.LINEAR;
+		case LOG10:
+			return AxisScale.LOG10;
+		case LOG2:
+			return AxisScale.LOG2;
+		default:
+			throw new IllegalStateException("unhandled enum: " + yAxis);
+		}
+	}
+
 	private static Limit toLimit(final LimitBy limitBy) {
 		switch (limitBy) {
 		case NO_LIMIT:

pdb-ui/src/main/java/org/lucares/pdbui/domain/PlotRequest.java

@@ -13,6 +13,8 @@ public class PlotRequest {
 
 	private LimitBy limitBy = LimitBy.NO_LIMIT;
 
+	private YAxis yAxis = YAxis.LINEAR;
+
 	private int limit = Integer.MAX_VALUE;
 
 	private String dateFrom;
@@ -91,4 +93,11 @@ public class PlotRequest {
 		this.dateRange = dateRange;
 	}
 
+	public YAxis getAxisScale() {
+		return yAxis;
+	}
+
+	public void setAxisScale(final YAxis yAxis) {
+		this.yAxis = yAxis;
+	}
 }

pdb-ui/src/main/java/org/lucares/pdbui/domain/YAxis.java

@@ -0,0 +1,5 @@
+package org.lucares.pdbui.domain;
+
+public enum YAxis {
+	LINEAR, LOG10, LOG2
+}