make computation of mean value optional

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

@@ -0,0 +1,5 @@
+package org.lucares.pdbui.domain;
+
+public enum Aggregate {
+	NONE, MEAN
+}

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

@@ -20,6 +20,8 @@ public class PlotRequest {
 	private String dateFrom;
 
 	private String dateRange;
+	
+	private Aggregate aggregate = Aggregate.NONE;
 
 	public String getQuery() {
 		return query;
@@ -100,4 +102,12 @@ public class PlotRequest {
 	public void setAxisScale(final YAxis yAxis) {
 		this.yAxis = yAxis;
 	}
+	
+	public void setAggregate(Aggregate aggregate) {
+		this.aggregate = aggregate;
+	}
+	
+	public Aggregate getAggregate() {
+		return aggregate;
+	}
 }