feat: delta view

src/main/java/io/jenkins/plugins/reporter/ReportAction.java

@@ -109,6 +109,11 @@ public ReportDetails getTarget() {
     public ReportResult getResult() {
         return result;
     }
+
+    @Whitelisted
+    public io.jenkins.plugins.reporter.model.Report getReport() {
+        return result.getReport();
+    }
 
     /**
      * Returns the name of the report.

src/main/java/io/jenkins/plugins/reporter/ReportDetails.java

@@ -146,7 +146,7 @@ public String getItemPieChartModel() {
      */
     @SuppressWarnings("unused") // Called by jelly view
     public ItemTableModel getTableModel() {
-        return new ItemTableModel(result.getReport(), getItem());
+        return new ItemTableModel(result.getReport(), getItem(), owner);
     }
 
     /**

src/main/java/io/jenkins/plugins/reporter/model/DisplayType.java

@@ -4,5 +4,6 @@ public enum DisplayType {
 
     ABSOLUTE,
     RELATIVE,
-    DUAL;
+    DUAL,
+    DELTA;
 }

src/main/java/io/jenkins/plugins/reporter/model/ItemTableModel.java

@@ -1,6 +1,9 @@
 package io.jenkins.plugins.reporter.model;
 
+import hudson.model.Run;
 import io.jenkins.plugins.datatables.TableColumn;
+import io.jenkins.plugins.reporter.ReportAction;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.text.CaseUtils;
 
 import java.io.UnsupportedEncodingException;
@@ -9,6 +12,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 /**
@@ -23,6 +27,10 @@ public class ItemTableModel {
 
     private final Item item;
 
+    private final Run<?, ?> owner;
+
+    private final Optional<Report> referenceReport;
+
     /**
      * Creates a new instance of {@link ItemTableModel}.
      *
@@ -32,11 +40,13 @@ public class ItemTableModel {
      * @param item
      *         the item to render
      */
-    public ItemTableModel(final Report report, final Item item) {
+    public ItemTableModel(final Report report, final Item item, final Run<?,?> owner) {
         super();
 
         this.report = report;
         this.item = item;
+        this.owner = owner;
+        this.referenceReport = getReferenceReport();
     }
 
     public String getId() {
@@ -60,7 +70,7 @@ public List<TableColumn> getColumns() {
     public List<ItemRow> getRows() {
         return item.getItems()
                 .stream()
-                .map(item -> new ItemRow(report, item, this))
+                .map(item -> new ItemRow(report, item, this, referenceReport))
                 .collect(Collectors.toList());
     }
 
@@ -73,7 +83,8 @@ protected TableColumn createResultAbsoluteColumn(String property) {
     }
 
     public String label(Integer value) {
-        return item.getLabel(report, value, value / (double) item.getTotal() * 100);
+        // This method is now only used for the total row, which doesn't show delta
+        return String.valueOf(value);
     }
 
     /**
@@ -83,6 +94,7 @@ public static class ItemRow {
 
         private final Report report;
         private final Item item;
+        private final Optional<Report> referenceReport;
 
         private final ItemTableModel model;
 
@@ -96,10 +108,11 @@ public static class ItemRow {
          * @param item
          *          the item to render.
          */
-        ItemRow(Report report, Item item, ItemTableModel model) {
+        ItemRow(Report report, Item item, ItemTableModel model, Optional<Report> referenceReport) {
             this.report = report;
             this.item = item;
             this.model = model;
+            this.referenceReport = referenceReport;
         }
 
         public String getId() {
@@ -145,15 +158,68 @@ public String getColor(String id) {
         }
 
         public String label(String id, Integer value) {
-            if (item.getResult().size() == 1) {
-                return item.getLabel(report, value, value / (double) model.getItem().getTotal() * 100);
+            switch (report.getDisplayType()) {
+                case DELTA:
+                    Integer previousValue = getLastSuccessBuildValue(id);
+                    return formatDeltaLabel(value, previousValue);
+                case RELATIVE:
+                     if (item.getResult().size() == 1) {
+                        return String.format("%.2f%%", value / (double) model.getItem().getTotal() * 100);
+                    }
+                    return String.format("%.2f%%", value / (double) item.getTotal() * 100);
+                case DUAL:
+                     if (item.getResult().size() == 1) {
+                        return String.format("%d (%.2f%%)", value, value / (double) model.getItem().getTotal() * 100);
+                    }
+                    return String.format("%d (%.2f%%)", value, value / (double) item.getTotal() * 100);
+                case ABSOLUTE:
+                default:
+                    return String.valueOf(value);
             }
-
-            return item.getLabel(report, value, value / (double) model.getItem().getResult().get(id) * 100);
         }
 
         public String tooltip(String id, double percentage) {
             return String.format("%s: %.2f%%", id, percentage);
         }
+
+        public Integer getLastSuccessBuildValue(String property) {
+            if (referenceReport.isPresent()) {
+                Optional<Item> referenceItem = referenceReport.get().findItem(item.getId());
+                if (referenceItem.isPresent()) {
+                    return referenceItem.get().getResult().get(property);
+                }
+            }
+            return null;
+        }
+
+        private String formatDeltaLabel(Integer currentValue, Integer previousValue) {
+            if (previousValue == null) {
+                return String.format("%d (+%d)", currentValue, currentValue);
+            }
+
+            int delta = currentValue - previousValue;
+
+            if (delta == 0) {
+                return currentValue.toString();
+            } else {
+                return String.format("%d (%s%d)", currentValue, delta > 0 ? "+" : "", delta);
+            }
+        }
+    }
+
+    private Optional<Report> getReferenceReport() {
+        if (owner == null) {
+            return Optional.empty();
+        }
+
+        Run<?, ?> lastSuccessfulBuild = owner.getParent().getLastSuccessfulBuild();
+        if (lastSuccessfulBuild != null) {
+            ReportAction action = lastSuccessfulBuild.getAction(ReportAction.class);
+            if (action != null) {
+                return Optional.of(action.getReport());
+            }
+        }
+
+        return Optional.empty();
     }
 }

src/main/resources/report/help-displayType.html

@@ -1,5 +1,6 @@
 <div>
-    This can be used to change the display of the displayed metrics within the distribution table. 
-    'absolute' shows the absolute values from the underlying files. 'relative', shows percentage values
-    and 'dual' shows the absolute value and additionally the relative frequency within the category.
+    This can be used to change the display of the displayed metrics within the distribution table.
+    'absolute' shows the absolute values from the underlying files. 'relative', shows percentage values,
+    'dual' shows the absolute value and additionally the relative frequency within the category and 'delta'
+    shows the absolute value and additionally the delta to the last successful build.
 </div>

src/main/resources/report/step.properties

@@ -1,3 +1,3 @@
 description.name=Choose a name for the report. The name is shown in the UI.
 description.displayType=Select the display type of the metrics in the table. Choose between 'absolute', \
-  'relative' and 'dual'. As default, if nothing is specified, 'absolute is used.
+  'relative', 'dual' and 'delta'. As default, if nothing is specified, 'absolute is used.