WIP

exist-core/src/main/java/org/exist/dom/persistent/AVLTreeNodeSet.java

@@ -27,6 +27,7 @@
 
 import javax.annotation.Nullable;
 import java.util.ArrayDeque;
+import java.util.Collections;
 import java.util.Deque;
 import java.util.Iterator;
 
@@ -459,12 +460,42 @@ private void setHasChanged() {
     }
 
     @Override
-    public boolean containsPrecedingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
+    public @Nullable NodeProxy containsPrecedingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
         throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
     }
 
     @Override
-    public boolean containsFollowingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
+    public @Nullable NodeProxy containsFollowingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
+        throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
+    }
+
+    @Override
+    public Iterator<NodeProxy> precedingSiblingsOf(final DocumentImpl doc, final NodeId nodeId) {
+        throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
+    }
+
+    @Override
+    public Iterator<NodeProxy> precedingSiblingsOfReverse(final DocumentImpl doc, final NodeId nodeId) {
+        throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
+    }
+
+    @Override
+    public Iterator<NodeProxy> precedingSiblingsOf(final DocumentImpl doc, final NodeId nodeId, final NodeRangeIterator it) {
+        throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
+    }
+
+    @Override
+    public Iterator<NodeProxy> followingSiblingsOf(final DocumentImpl doc, final NodeId nodeId) {
+        throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
+    }
+
+    @Override
+    public Iterator<NodeProxy> followingSiblingsOfReverse(final DocumentImpl doc, final NodeId nodeId) {
+        throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
+    }
+
+    @Override
+    public Iterator<NodeProxy> followingSiblingsOf(final DocumentImpl doc, final NodeId nodeId, final NodeRangeIterator it) {
         throw new UnsupportedOperationException("TODO(AR) do we need to implement this?");
     }
 

exist-core/src/main/java/org/exist/dom/persistent/AbstractArrayNodeSet.java

@@ -92,7 +92,7 @@ public void add(final NodeProxy proxy, final int sizeHint) {
 
         addInternal(proxy, sizeHint);
 
-        this.isSorted = false;
+        this.isSorted = false; // TODO(AR) make this more intelligent by comparing the entry we are adding with the last entry added; if they are added in order we don't need to sort them! Then also apply that approach to other NodeSet implementations
         setHasChanged();
         checkItemType(proxy.getType());
         this.lastAdded = proxy;

exist-core/src/main/java/org/exist/dom/persistent/BackwardNodeRangeIterator.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2014, Evolved Binary Ltd
+ *
+ * This file was originally ported from FusionDB to eXist-db by
+ * Evolved Binary, for the benefit of the eXist-db Open Source community.
+ * Only the ported code as it appears in this file, at the time that
+ * it was contributed to eXist-db, was re-licensed under The GNU
+ * Lesser General Public License v2.1 only for use in eXist-db.
+ *
+ * This license grant applies only to a snapshot of the code as it
+ * appeared when ported, it does not offer or infer any rights to either
+ * updates of this source code or access to the original source code.
+ *
+ * The GNU Lesser General Public License v2.1 only license follows.
+ *
+ * ---------------------------------------------------------------------
+ *
+ * Copyright (C) 2014, Evolved Binary Ltd
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; version 2.1.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+package org.exist.dom.persistent;
+
+import javax.annotation.Nullable;
+import java.util.NoSuchElementException;
+
+/**
+ * Iterate backward over a range of nodes.
+ *
+ * @author <a href="mailto:adam@evolvedbinary.com">Adam Retter</a>
+ */
+public class BackwardNodeRangeIterator implements NodeRangeIterator {
+  @Nullable private NodeProxy[] nodes;
+  private int idx;
+  private int startIdx;
+
+  public BackwardNodeRangeIterator() {
+    this.nodes = null;
+    this.idx = -1;
+    this.startIdx = 0;
+  }
+
+  /**
+   * @param nodes the nodes array.
+   * @param startIdx the starting index within {@link #nodes}.
+   * @param endIdx the ending index within {@link #nodes}.
+   */
+  public BackwardNodeRangeIterator(final NodeProxy[] nodes, final int startIdx, final int endIdx) {
+    this.nodes = nodes;
+    this.startIdx = startIdx;
+    this.idx = endIdx;
+  }
+
+  @Override
+  public boolean hasNext() {
+    return idx >= startIdx;
+  }
+
+  @Override
+  public NodeProxy next() {
+    if (!hasNext() || nodes == null) {
+      throw new NoSuchElementException();
+    }
+    return nodes[idx--];
+  }
+
+  @Override
+  public void reset(final NodeProxy[] nodes, final int startIdx, final int endIdx) {
+    this.nodes = nodes;
+    this.startIdx = startIdx;
+    this.idx = endIdx;
+  }
+}

exist-core/src/main/java/org/exist/dom/persistent/EmptyNodeSet.java

@@ -27,6 +27,8 @@
 import org.exist.xquery.value.SequenceIterator;
 import org.w3c.dom.Node;
 
+import javax.annotation.Nullable;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 
@@ -109,13 +111,43 @@ public NodeProxy parentWithChild(final DocumentImpl doc, final NodeId nodeId,
     }
 
     @Override
-    public boolean containsPrecedingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
-        return false;
+    public @Nullable NodeProxy containsPrecedingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
+        return null;
     }
 
     @Override
-    public boolean containsFollowingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
-        return false;
+    public @Nullable NodeProxy containsFollowingSiblingOf(final DocumentImpl doc, final NodeId nodeId) {
+        return null;
+    }
+
+    @Override
+    public Iterator<NodeProxy> precedingSiblingsOf(final DocumentImpl doc, final NodeId nodeId) {
+        return Collections.emptyIterator();
+    }
+
+    @Override
+    public Iterator<NodeProxy> precedingSiblingsOfReverse(final DocumentImpl doc, final NodeId nodeId) {
+        return Collections.emptyIterator();
+    }
+
+    @Override
+    public Iterator<NodeProxy> precedingSiblingsOf(final DocumentImpl doc, final NodeId nodeId, final NodeRangeIterator it) {
+        return Collections.emptyIterator();
+    }
+
+    @Override
+    public Iterator<NodeProxy> followingSiblingsOf(final DocumentImpl doc, final NodeId nodeId) {
+        return Collections.emptyIterator();
+    }
+
+    @Override
+    public Iterator<NodeProxy> followingSiblingsOfReverse(final DocumentImpl doc, final NodeId nodeId) {
+        return Collections.emptyIterator();
+    }
+
+    @Override
+    public Iterator<NodeProxy> followingSiblingsOf(final DocumentImpl doc, final NodeId nodeId, final NodeRangeIterator it) {
+        return Collections.emptyIterator();
     }
 
     @Override