added helper methods for iterating through next/previous nodes or elements on the DOM

libraries/stdlib/src/dom/Dom.kt

@@ -1,6 +1,7 @@
 package kotlin.dom
 
 import kotlin.*
+import kotlin.support.*
 import kotlin.util.*
 import java.util.*
 import org.w3c.dom.*
@@ -190,6 +191,45 @@ fun Element.get(selector: String): List<Element> {
     }
 }
 
+/** Returns an [[Iterator]] over the next siblings of this node */
+fun Node.nextSiblings() : Iterator<Node> = NextSiblingIterator(this)
+
+protected class NextSiblingIterator(var node: Node) : AbstractIterator<Node>() {
+
+    override fun computeNext(): Node? {
+        val next = node.getNextSibling()
+        if (next != null) {
+            node = next
+            return next
+        } else {
+            done()
+            return null
+        }
+    }
+}
+/** Returns an [[Iterator]] over the next siblings of this node */
+fun Node.previousSiblings() : Iterator<Node> = PreviousSiblingIterator(this)
+
+protected class PreviousSiblingIterator(var node: Node) : AbstractIterator<Node>() {
+
+    override fun computeNext(): Node? {
+        val next = node.getPreviousSibling()
+        if (next != null) {
+            node = next
+            return next
+        } else {
+            done()
+            return null
+        }
+    }
+}
+
+/** Returns an [[Iterator]] of all the next [[Element]] siblings */
+fun Node.nextElements(): Iterator<Element> = nextSiblings().filterIs<Node, Element>()
+
+/** Returns an [[Iterator]] of all the previous [[Element]] siblings */
+fun Node.previousElements(): Iterator<Element> = previousSiblings().filterIs<Node, Element>()
+
 /** Returns the attribute value or empty string if its not present */
 inline fun Element.attribute(name: String): String {
     return this.getAttribute(name) ?: ""
@@ -271,7 +311,7 @@ inline fun NodeList?.toElementList(): List<Element> {
 fun NodeList?.toXmlString(xmlDeclaration: Boolean = false): String {
     return if (this == null)
         "" else {
-        this.toList().toXmlString(xmlDeclaration)
+        nodesToXmlString(this.toList(), xmlDeclaration)
     }
 }
 

libraries/stdlib/src/dom/DomJVM.kt

@@ -17,6 +17,7 @@ import javax.xml.transform.OutputKeys
 import java.lang.Iterable
 import java.util.List
 import java.util.Collection
+import java.io.Writer
 
 /** Creates a new document with the given document builder*/
 fun createDocument(builder: DocumentBuilder): Document {
@@ -39,35 +40,26 @@ fun createTransformer(source: Source? = null, factory: TransformerFactory = Tran
 }
 
 /** Converts the node to an XML String */
-fun Node.toXmlString(xmlDeclaration: Boolean = this is Document): String {
-    return nodeToXmlString(this, xmlDeclaration)
+fun Node.toXmlString(xmlDeclaration: Boolean = false): String {
+    val writer = StringWriter()
+    writeXmlString(writer, xmlDeclaration)
+    return writer.toString().sure()
+}
+
+/** Converts the node to an XML String and writes it to the given [[Writer]] */
+fun Node.writeXmlString(writer: Writer, xmlDeclaration: Boolean): Unit {
+    val transformer = createTransformer()
+    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, if (xmlDeclaration) "no" else "yes")
+    transformer.transform(DOMSource(this), StreamResult(writer))
 }
 
 /** Converts the collection of nodes to an XML String */
-fun java.lang.Iterable<Node>.toXmlString(xmlDeclaration: Boolean = false): String {
+fun nodesToXmlString(nodes: Iterable<Node>, xmlDeclaration: Boolean = false): String {
     // TODO this should work...
     // return this.map<Node,String>{it.toXmlString()}.join("")
     val builder = StringBuilder()
-    for (n in this) {
+    for (n in nodes) {
         builder.append(n.toXmlString(xmlDeclaration))
     }
     return builder.toString().sure()
-}
-
-
-/*
-fun Document.toXmlString(xmlDeclaration: Boolean = true): String {
-    return nodeToXmlString(this, xmlDeclaration)
-}
-*/
-
-/** Converts the node to an XML String */
-fun nodeToXmlString(node: Node, xmlDeclaration: Boolean): String {
-    val transformer = createTransformer()
-    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, if (xmlDeclaration) "no" else "yes")
-    val buffer = StringWriter()
-    transformer.transform(DOMSource(node), StreamResult(buffer))
-    return buffer.toString().sure()
-
-}
-
+}