Prevent race-condition induced sporadic error in Escalator (#17258)

Change-Id: I624c44056d43a6a3205be46a748070f269a3c3e3

2 files changed, 174 insertions, 10 deletions

diff --git a/client/src/com/vaadin/client/widgets/Escalator.java b/client/src/com/vaadin/client/widgets/Escalator.java
index 5b3d4e1b70..7b0bb3bfe4 100644
--- a/client/src/com/vaadin/client/widgets/Escalator.java
+++ b/client/src/com/vaadin/client/widgets/Escalator.java
@@ -2767,17 +2767,33 @@ public class Escalator extends Widget implements RequiresResize,
                     // move the surrounding rows to their correct places.
                     double rowTop = (unupdatedLogicalStart + (end - start))
                             * getDefaultRowHeight();
-                    final ListIterator<TableRowElement> i = visualRowOrder
-                            .listIterator(visualTargetIndex + (end - start));
 
-                    int logicalRowIndexCursor = unupdatedLogicalStart;
-                    while (i.hasNext()) {
-                        rowTop += spacerContainer
-                                .getSpacerHeight(logicalRowIndexCursor++);
-
-                        final TableRowElement tr = i.next();
-                        setRowPosition(tr, 0, rowTop);
-                        rowTop += getDefaultRowHeight();
+                    // TODO: Get rid of this try/catch block by fixing the
+                    // underlying issue. The reason for this erroneous behavior
+                    // might be that Escalator actually works 'by mistake', and
+                    // the order of operations is, in fact, wrong.
+                    try {
+                        final ListIterator<TableRowElement> i = visualRowOrder
+                                .listIterator(visualTargetIndex + (end - start));
+
+                        int logicalRowIndexCursor = unupdatedLogicalStart;
+                        while (i.hasNext()) {
+                            rowTop += spacerContainer
+                                    .getSpacerHeight(logicalRowIndexCursor++);
+
+                            final TableRowElement tr = i.next();
+                            setRowPosition(tr, 0, rowTop);
+                            rowTop += getDefaultRowHeight();
+                        }
+                    } catch (Exception e) {
+                        Logger logger = getLogger();
+                        logger.warning("Ignored out-of-bounds row element access");
+                        logger.warning("Escalator state: start=" + start
+                                + ", end=" + end + ", visualTargetIndex="
+                                + visualTargetIndex
+                                + ", visualRowOrder.size()="
+                                + visualRowOrder.size());
+                        logger.warning(e.toString());
                     }
                 }
 
diff --git a/uitest/src/com/vaadin/tests/components/grid/GridFastAsyncUpdate.java b/uitest/src/com/vaadin/tests/components/grid/GridFastAsyncUpdate.java
new file mode 100644
index 0000000000..31fe0275a5
--- /dev/null
+++ b/uitest/src/com/vaadin/tests/components/grid/GridFastAsyncUpdate.java
@@ -0,0 +1,148 @@
+package com.vaadin.tests.components.grid;
+
+import java.util.Calendar;
+import java.util.Random;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.logging.Level;
+
+import com.vaadin.annotations.Push;
+import com.vaadin.annotations.Theme;
+import com.vaadin.data.Item;
+import com.vaadin.data.util.IndexedContainer;
+import com.vaadin.event.SelectionEvent;
+import com.vaadin.event.SelectionEvent.SelectionListener;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.Button.ClickEvent;
+import com.vaadin.ui.Grid;
+import com.vaadin.ui.Grid.SelectionMode;
+import com.vaadin.ui.HorizontalLayout;
+import com.vaadin.ui.VerticalLayout;
+
+@Push
+@Theme("valo")
+@SuppressWarnings("serial")
+public class GridFastAsyncUpdate extends AbstractTestUI {
+
+    private final Runnable addRowsTask = new Runnable() {
+        @Override
+        public void run() {
+            System.out.println("Logging...");
+            try {
+                Random random = new Random();
+                while (!Thread.currentThread().isInterrupted()) {
+                    Thread.sleep(random.nextInt(100));
+
+                    GridFastAsyncUpdate.this.access(new Runnable() {
+                        @SuppressWarnings("unchecked")
+                        @Override
+                        public void run() {
+
+                            ++counter;
+                            Item item = container.addItem(counter);
+                            item.getItemProperty("sequenceNumber").setValue(
+                                    String.valueOf(counter));
+                            item.getItemProperty("millis").setValue(
+                                    String.valueOf(Calendar.getInstance()
+                                            .getTimeInMillis() - loggingStart));
+                            item.getItemProperty("level").setValue(
+                                    Level.INFO.toString());
+                            item.getItemProperty("message").setValue("Message");
+                            if (grid != null && !scrollLock) {
+                                grid.scrollToEnd();
+                            }
+                        }
+                    });
+                }
+            } catch (InterruptedException e) {
+                System.out.println("logging thread interrupted");
+            }
+        }
+    };
+
+    private int counter;
+
+    private Grid grid;
+    private IndexedContainer container;
+    private long loggingStart;
+    private volatile boolean scrollLock = false;
+
+    @Override
+    protected void setup(VaadinRequest vaadinRequest) {
+        final VerticalLayout layout = new VerticalLayout();
+        layout.setSizeFull();
+        layout.setMargin(true);
+        addComponent(layout);
+
+        HorizontalLayout buttons = new HorizontalLayout();
+        layout.addComponent(buttons);
+
+        final ExecutorService logExecutor = Executors.newSingleThreadExecutor();
+
+        final Button logButton = new Button("Start logging");
+        logButton.addClickListener(new Button.ClickListener() {
+            @Override
+            public void buttonClick(ClickEvent event) {
+                if ("Start logging".equals(logButton.getCaption())) {
+                    loggingStart = Calendar.getInstance().getTimeInMillis();
+                    logExecutor.submit(addRowsTask);
+                    logButton.setCaption("Stop logging");
+                } else {
+                    System.out.println("Stop logging...");
+                    try {
+                        logExecutor.shutdownNow();
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                    logButton.setCaption("Start logging");
+                }
+            }
+        });
+        buttons.addComponent(logButton);
+
+        final Button scrollButton = new Button("Stop scrolling");
+        scrollButton.addClickListener(new Button.ClickListener() {
+            @Override
+            public void buttonClick(ClickEvent event) {
+                if (!scrollLock) {
+                    System.out.println("Stop scrolling");
+                    scrollButton.setCaption("Start scrolling");
+                    scrollLock = true;
+                } else {
+                    System.out.println("Start scrolling");
+                    scrollButton.setCaption("Stop scrolling");
+                    scrollLock = false;
+                }
+            }
+        });
+        buttons.addComponent(scrollButton);
+
+        container = new IndexedContainer();
+        container.addContainerProperty("sequenceNumber", String.class, null);
+        container.addContainerProperty("millis", String.class, null);
+        container.addContainerProperty("level", String.class, null);
+        container.addContainerProperty("message", String.class, null);
+
+        grid = new Grid(container);
+        grid.setWidth("100%");
+        grid.setImmediate(true);
+        grid.setSelectionMode(SelectionMode.SINGLE);
+        grid.addSelectionListener(new SelectionListener() {
+            @Override
+            public void select(final SelectionEvent event) {
+                if (grid.getSelectedRow() != null) {
+                    disableScroll();
+                }
+            }
+        });
+
+        layout.addComponent(grid);
+        layout.setExpandRatio(grid, 1.0f);
+    }
+
+    protected void disableScroll() {
+        scrollLock = true;
+    }
+}
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