Merge pull request jenkinsci#53 from jenkinsci/jenkins-39026

[FIXED JENKINS-39026] Add an abstract base class for simple ViewBranchFilter

src/main/java/jenkins/branch/SimpleViewBranchFilter.java

@@ -0,0 +1,108 @@
+package jenkins.branch;
+
+import hudson.model.Item;
+import hudson.model.ItemGroup;
+import hudson.model.TopLevelItem;
+import hudson.model.View;
+import hudson.views.ViewJobFilter;
+import java.lang.reflect.Method;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * Base class for a {@link ViewJobFilter} that will filter based on the {@link Branch} that a job in a
+ * {@link MultiBranchProject} belongs to.
+ *
+ * @since FIXME
+ */
+public abstract class SimpleViewBranchFilter extends ViewJobFilter {
+
+    /**
+     * Optimization to avoid processing the less common case of removing already added items.
+     */
+    private final boolean processExclusions = isExcludedOverridden();
+
+    /**
+     * {@inheritDoc}
+     */
+    @SuppressWarnings("unchecked")
+    @Override
+    public final List<TopLevelItem> filter(List<TopLevelItem> added, List<TopLevelItem> all, View filteringView) {
+        ItemGroup<? extends TopLevelItem> itemGroup = filteringView.getOwnerItemGroup();
+        if (itemGroup instanceof MultiBranchProject) {
+            // fast path
+            MultiBranchProject project = (MultiBranchProject) itemGroup;
+            BranchProjectFactory factory = project.getProjectFactory();
+            if (processExclusions) {
+                for (Iterator<TopLevelItem> iterator = added.iterator(); iterator.hasNext(); ) {
+                    TopLevelItem i = iterator.next();
+                    if (factory.isProject(i) && isExcluded(factory.getBranch(factory.asProject(i)))) {
+                        iterator.remove();
+                    }
+                }
+            }
+            for (TopLevelItem i : all) {
+                if (factory.isProject(i) && isIncluded(factory.getBranch(factory.asProject(i)))) {
+                    added.add(i);
+                }
+            }
+        } else {
+            // ok this may be a view pulling in all child items, so we need to check each item as we go
+            if (processExclusions) {
+                for (Iterator<TopLevelItem> iterator = added.iterator(); iterator.hasNext(); ) {
+                    TopLevelItem i = iterator.next();
+                    ItemGroup<? extends Item> parent = i.getParent();
+                    if (parent instanceof MultiBranchProject) {
+                        BranchProjectFactory factory = ((MultiBranchProject) parent).getProjectFactory();
+                        if (factory.isProject(i) && isExcluded(factory.getBranch(factory.asProject(i)))) {
+                            iterator.remove();
+                        }
+                    }
+                }
+            }
+            for (TopLevelItem i : all) {
+                ItemGroup<? extends Item> parent = i.getParent();
+                if (parent instanceof MultiBranchProject) {
+                    BranchProjectFactory factory = ((MultiBranchProject) parent).getProjectFactory();
+                    if (factory.isProject(i) && isIncluded(factory.getBranch(factory.asProject(i)))) {
+                        added.add(i);
+                    }
+                }
+            }
+        }
+        return added;
+    }
+
+    /**
+     * Tests if the supplied branch should be excluded.
+     *
+     * @param branch the {@link Branch}.
+     * @return {@code true} to exclude the branch from the view.
+     */
+    public boolean isExcluded(Branch branch) {
+        return false;
+    }
+
+    /**
+     * Tests if the supplied branch should be included. Inclusion wins over exclusion.
+     *
+     * @param branch the {@link Branch}.
+     * @return {@code true} to include the branch from the view.
+     */
+    public abstract boolean isIncluded(Branch branch);
+
+    /**
+     * Checks if {@link #isExcluded(Branch)} has been overridden.
+     *
+     * @return {@code true} if we need to process the added list, {@code false} if we can safely assume
+     * {@link #isExcluded(Branch)} will always return {@code false}
+     */
+    private boolean isExcludedOverridden() {
+        try {
+            Method isExcluded = getClass().getMethod("isExcluded", Branch.class);
+            return isExcluded.getDeclaringClass() != SimpleViewBranchFilter.class;
+        } catch (NoSuchMethodException e) {
+            return false;
+        }
+    }
+}