OAK-11607 minor fixes

Author: joerghoh

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/tree/impl/AbstractTree.java

@@ -24,17 +24,12 @@
 import static org.apache.jackrabbit.oak.api.Type.NAMES;
 import static org.apache.jackrabbit.oak.plugins.tree.TreeConstants.OAK_CHILD_ORDER;
 
-import java.util.ArrayList;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Objects;
-import java.util.Set;
-
 import org.apache.jackrabbit.oak.api.PropertyState;
 import org.apache.jackrabbit.oak.api.Tree;
 import org.apache.jackrabbit.oak.commons.PathUtils;
 import org.apache.jackrabbit.oak.commons.collections.IterableUtils;
-import org.apache.jackrabbit.oak.commons.collections.SetUtils;
 import org.apache.jackrabbit.oak.commons.conditions.Validate;
 import org.apache.jackrabbit.oak.plugins.index.IndexConstants;
 import org.apache.jackrabbit.oak.plugins.index.reference.NodeReferenceConstants;

oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/tree/impl/OrderedChildnameIterable.java

@@ -37,6 +37,11 @@ public class OrderedChildnameIterable implements Iterable<String> {
 
     final OrderedChildnameIterator iter;
 
+    /**
+     * Create an iterator, which returns all children in the correct order
+     * @param orderedChildren the children defined by the :childrenOrder property
+     * @param allChildren all children
+     */
     public OrderedChildnameIterable (Iterable<String> orderedChildren, Iterable<String> allChildren) {
         iter = new OrderedChildnameIterator(orderedChildren,allChildren);
     }
@@ -53,9 +58,6 @@ public class OrderedChildnameIterator implements Iterator<String> {
 
         private String nextResult;
 
-        // lazily populated by elements from the allChildren iterable
-        private final Set<String> allChildrenSet = new HashSet<>();
-
         private final List<String> nonOrderedChildren = new ArrayList<>();
         private Iterator<String> nonOrderedChildrenIterator = null;
 
@@ -93,7 +95,7 @@ private String getNextElement() {
          * Consume the next element from the orderedChild list and validates that it's actually present
          * @return the next ordered child or  {code null} if all ordered children have already been returned
          */
-        String getNextOrderedChild() {
+        private String getNextOrderedChild() {
             String current = null;
             // check that this element is actually present in the allChildren iterable
             while (current == null && orderedChildren.hasNext()) {
@@ -107,7 +109,12 @@ String getNextOrderedChild() {
             return null;
         }
 
-        boolean isOrderedChildPresent(String orderedChildName) {
+        /**
+         * Check if the provided childname is also provided by the allChildren iterator.
+         * @param orderedChildName
+         * @return true if childname is a valid child, false otherwise
+         */
+        private boolean isOrderedChildPresent(String orderedChildName) {
             // read from the allChildren iterator until it's a hit or exhausted
             while (!nonOrderedChildren.contains(orderedChildName) && allChildren.hasNext()) {
                 nonOrderedChildren.add(allChildren.next());

oak-core/src/test/java/org/apache/jackrabbit/oak/plugins/tree/impl/OrderedChildnameIterableTest.java

@@ -90,11 +90,18 @@ public void orderedChildren() {
 
     @Test
     public void orderedChildrenWithNonExistingOrderedChild() {
-        // the ordered list contains a non-existing childname, which is not part of children list
+        // the ordered list contains non-existing childnames, which are not part of children list
         OrderedChildnameIterable iterable = new OrderedChildnameIterable(List.of("4","nonexisting1","5","nonexisting2"),ALL_CHILDREN);
         Assert.assertEquals(List.of("4","5","1","2","3"), iterableToList(iterable));
     }
 
+    @Test
+    public void orderedChildrenWithOnlyNonExistingOrderedChild() {
+        // the ordered list contains non-existing childnames, which are not part of children list
+        OrderedChildnameIterable iterable = new OrderedChildnameIterable(List.of("nonexisting"),ALL_CHILDREN);
+        Assert.assertEquals(List.of("1","2","3","4","5"), iterableToList(iterable));
+    }
+
     @Test
     public void onlyOrderedChildrenAvailable() {
         // the orderedChildren property is populated, but no children are available
@@ -109,8 +116,7 @@ public void testLazyLoading() {
 
         OrderedChildnameIterable iterable = new OrderedChildnameIterable(
             List.of("4", "1"),
-            trackingAllChildren
-        );
+            trackingAllChildren);
 
         Iterator<String> iterator = iterable.iterator();