Improve / Fix isDrawable

* PieChart: Fix condition for "...at least one data point"
* others: Sync docs and code e.g. "at least two data points" -> ">= 2" is better readable than "> 1"

Co-Authored-By: Oleh Astappiev <[email protected]>

Author: AB-xdev

chartjs-java-model/src/main/java/software/xdev/chartjs/model/charts/PieChart.java

@@ -76,7 +76,7 @@ public boolean isDrawable()
 	{
 		for(final PieDataset dataset : this.getData().getDatasets())
 		{
-			if(dataset.getData().size() > 1)
+			if(!dataset.getData().isEmpty())
 			{
 				return true;
 			}

chartjs-java-model/src/main/java/software/xdev/chartjs/model/charts/PolarChart.java

@@ -76,7 +76,7 @@ public boolean isDrawable()
 	{
 		for(final PolarDataset dataset : this.getData().getDatasets())
 		{
-			if(dataset.getData().size() > 1)
+			if(dataset.getData().size() >= 2)
 			{
 				return true;
 			}

chartjs-java-model/src/main/java/software/xdev/chartjs/model/charts/RadarChart.java

@@ -76,7 +76,7 @@ public boolean isDrawable()
 	{
 		for(final RadarDataset dataset : this.getData().getDatasets())
 		{
-			if(dataset.getData().size() > 2)
+			if(dataset.getData().size() >= 3)
 			{
 				return true;
 			}