Factored out RunListProgressiveRendering supertype.

core/src/main/java/jenkins/widgets/BuildListTable.java

@@ -27,50 +27,14 @@ package jenkins.widgets;
 import hudson.Functions;
 import hudson.model.BallColor;
 import hudson.model.Run;
-import java.util.ArrayList;
-import java.util.List;
-import jenkins.util.ProgressiveRendering;
-import net.sf.json.JSON;
-import net.sf.json.JSONArray;
 import net.sf.json.JSONObject;
 import org.kohsuke.accmod.Restricted;
 import org.kohsuke.accmod.restrictions.DoNotUse;
 
 @Restricted(DoNotUse.class) // only for buildListTable.jelly
-public class BuildListTable extends ProgressiveRendering {
+public class BuildListTable extends RunListProgressiveRendering {
 
-    private final List<JSONObject> results = new ArrayList<JSONObject>();
-    private Iterable<? extends Run<?,?>> builds;
-
-    /** Jelly cannot call a constructor with arguments. */
-    public void setBuilds(Iterable<? extends Run<?,?>> builds) {
-        this.builds = builds;
-    }
-
-    @Override protected void compute() throws Exception {
-        double decay = 1;
-        for (Run<?,?> build : builds) {
-            if (canceled()) {
-                return;
-            }
-            JSONObject element = new JSONObject();
-            calculate(build, element);
-            synchronized (results) {
-                results.add(element);
-            }
-            // Since we cannot predict how many there will be, just show an ever-growing bar.
-            decay *= .99;
-            progress(1 - decay);
-        }
-    }
-
-    @Override protected synchronized JSON data() {
-        JSONArray d = JSONArray.fromObject(results);
-        results.clear();
-        return d;
-    }
-
-    private void calculate(Run<?,?> build, JSONObject element) {
+    @Override protected void calculate(Run<?,?> build, JSONObject element) {
         BallColor iconColor = build.getIconColor();
         element.put("iconColorOrdinal", iconColor.ordinal());
         element.put("iconColorDescription", iconColor.getDescription());

core/src/main/java/jenkins/widgets/RunListProgressiveRendering.java

+/*
+ * The MIT License
+ *
+ * Copyright 2013 Jesse Glick.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.widgets;
+
+import hudson.model.Run;
+import hudson.util.RunList;
+import java.util.ArrayList;
+import java.util.List;
+import jenkins.util.ProgressiveRendering;
+import net.sf.json.JSON;
+import net.sf.json.JSONArray;
+import net.sf.json.JSONObject;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
+
+/**
+ * Makes it possible to incrementally render some information from a {@link RunList}.
+ */
+@Restricted(NoExternalUse.class)
+public abstract class RunListProgressiveRendering extends ProgressiveRendering {
+
+    /**
+     * Since we cannot predict how many runs there will be, just show an ever-growing progress bar.
+     * The first increment will be sized as if this many runs will be in the total,
+     * but then like Zeno’s paradox we will never seem to finish until we actually do.
+     */
+    private static final double MAX_LIKELY_RUNS = 20;
+    private final List<JSONObject> results = new ArrayList<JSONObject>();
+    private Iterable<? extends Run<?,?>> builds;
+
+    /** Jelly cannot call a constructor with arguments. */
+    public void setBuilds(Iterable<? extends Run<?,?>> builds) {
+        this.builds = builds;
+    }
+
+    @Override protected void compute() throws Exception {
+        double decay = 1;
+        for (Run<?,?> build : builds) {
+            if (canceled()) {
+                return;
+            }
+            JSONObject element = new JSONObject();
+            calculate(build, element);
+            synchronized (results) {
+                results.add(element);
+            }
+            decay *= (1 - 1 / MAX_LIKELY_RUNS);
+            progress(1 - decay);
+        }
+    }
+
+    @Override protected synchronized JSON data() {
+        JSONArray d = JSONArray.fromObject(results);
+        results.clear();
+        return d;
+    }
+
+    protected abstract void calculate(Run<?,?> build, JSONObject element);
+}