Helper class for xml:lang handling.

2 files changed, 50 insertions, 0 deletions

diff --git a/org/madore/damlengine/DamlEngine.java b/org/madore/damlengine/DamlEngine.java
index 03e089d..4861f06 100644
--- a/org/madore/damlengine/DamlEngine.java
+++ b/org/madore/damlengine/DamlEngine.java
@@ -9,6 +9,7 @@ import org.apache.xerces.jaxp.DocumentBuilderFactoryImpl;
 
 public final class DamlEngine {
 
+    public static final String XML_NS = "http://www.w3.org/XML/1998/namespace";
     public static final String DAML_NS = "http://www.madore.org/~david/NS/daml/";
 
     private DamlEngine() { }  // Forbid instantiation
diff --git a/org/madore/damlengine/LangHelper.java b/org/madore/damlengine/LangHelper.java
new file mode 100644
index 0000000..280e5ca
--- /dev/null
+++ b/org/madore/damlengine/LangHelper.java
@@ -0,0 +1,49 @@
+package org.madore.damlengine;
+
+import org.w3c.dom.Node;
+import org.w3c.dom.Element;
+
+public class LangHelper {
+
+    public static final String LANG = "lang";
+
+    public static String getLangNorec(Node node) {
+	if ( node instanceof Element )
+	    return ((Element)node).getAttributeNS(DamlEngine.XML_NS, LANG);
+	else
+	    return null;
+    }
+
+    public static void setLangNorec(Element node, String lang) {
+	if ( lang == null )
+	    throw new Error("lang is null in setLangNorec");
+	node.setAttributeNS(DamlEngine.XML_NS, LANG, lang);
+    }
+
+    public static void unsetLangNorec(Element node) {
+	node.removeAttributeNS(DamlEngine.XML_NS, LANG);
+    }
+
+    public static String getLangRec(Node node) {
+	// node may be null (in which case, return null)
+	while ( node != null ) {
+	    String lang = getLangNorec(node);
+	    if ( lang != null )
+		return lang;
+	    node = node.getParentNode();
+	}
+	return null;
+    }
+
+    public static void setLangRec(Element node, String lang) {
+	if ( lang == null )
+	    throw new Error("lang is null in setLangRec");
+	Node parentNode = node.getParentNode();
+	String parentLang = (parentNode!=null)?getLangNorec(parentNode):null;
+	if ( parentLang != null && lang.equals(parentLang) )
+	    unsetLangNorec(node);
+	else
+	    setLangNorec(node,lang);
+    }
+
+}