Replace old jrobin with rrd4j 3.5 (ticket #2684)

2019-02-10
From https://github.com/rrd4j/rrd4j/releases
Copyright (c) 2001-2005 Sasa Markovic and Ciaran Treanor.
Copyright (c) 2011 The OpenNMS Group, Inc.
Copyright 2011 The RRD4J Authors.
Apache 2.0 and LGPLv2.1

Unmodified as a base for future merges, except for omitted
files listed below.
This rev will not work; font patch to follow in next revision.

Following directories and files omitted:
converter/
core/RrdBerkeleyDbBackendFactory.java
core/RrdBerkeleyDbBackend.java
core/RrdMongoDBBackendFactory.java
core/RrdMongoDBBackend.java
demo/
graph/RrdGraphDefTemplate.java
inspector/
eu/bengreen/data/utility/

apps/jrobin/java/src/org/rrd4j/graph/ConstantArea.java

@@ -0,0 +1,29 @@
+package org.rrd4j.graph;
+
+import java.awt.Paint;
+import java.util.Arrays;
+
+import org.rrd4j.data.DataProcessor;
+
+public class ConstantArea extends Area {
+    private final double value;
+
+    ConstantArea(double value, Paint color, SourcedPlotElement parent) {
+        super(Double.toString(value), color, parent);
+        this.value = value;
+    }
+
+    void assignValues(DataProcessor dproc) {
+        values = new double[dproc.getTimestamps().length];
+        Arrays.fill(values, value);
+        if(parent != null) {
+            double[] parentValues = parent.getValues();
+            for (int i = 0; i < values.length; i++) {
+                if (! Double.isNaN(parentValues[i])){
+                    values[i] += parentValues[i];
+                }
+            }
+        }
+    }
+
+}