Fix #45: swapped arguments in AttributeEventImpl.writeUsing()

release-notes/VERSION

@@ -12,6 +12,8 @@ Project: Stax2 API
  (contributed by @winfriedgerlach)
 #44: Free memory after `Stax2Util.ByteAggregator.aggregateAll()`
  (contributed by @winfriedgerlach)
+#45: Fix swapped arguments in `AttributeEventImpl.writeUsing()`
+ (contributed by @winfriedgerlach)
 - Branch "master" renamed as "main"
 
 4.3.0 (31-Mar-2026)

src/main/java/org/codehaus/stax2/ri/evt/AttributeEventImpl.java

@@ -86,8 +86,8 @@ public void writeAsEncodedUnicode(Writer w)
     public void writeUsing(XMLStreamWriter2 w) throws XMLStreamException
     {
         QName n = mName;
-        w.writeAttribute(n.getPrefix(), n.getLocalPart(),
-                         n.getNamespaceURI(), mValue);
+        w.writeAttribute(n.getPrefix(), n.getNamespaceURI(),
+                         n.getLocalPart(), mValue);
     }
 
     /*

src/test/java/org/codehaus/stax2/ri/evt/AttributeEventImplTest.java

@@ -0,0 +1,56 @@
+package org.codehaus.stax2.ri.evt;
+
+import java.io.StringWriter;
+
+import javax.xml.namespace.QName;
+import javax.xml.stream.XMLOutputFactory;
+import javax.xml.stream.XMLStreamException;
+
+import org.codehaus.stax2.XMLStreamWriter2;
+import org.codehaus.stax2.ri.Stax2WriterAdapter;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Tests for {@link AttributeEventImpl}, mostly regarding
+ * [stax2-api#45]: swapped arguments in {@code writeUsing()}.
+ */
+public class AttributeEventImplTest
+{
+    @Test
+    public void testWriteUsingWithNamespace() throws Exception
+    {
+        AttributeEventImpl attr = new AttributeEventImpl(null,
+                new QName("urn:test", "attr", "p"), "value", true);
+        assertEquals("<root xmlns:p=\"urn:test\" p:attr=\"value\"></root>",
+                writeWithAttribute("p", "urn:test", attr));
+    }
+
+    @Test
+    public void testWriteUsingWithoutNamespace() throws Exception
+    {
+        AttributeEventImpl attr = new AttributeEventImpl(null,
+                new QName("attr"), "value", true);
+        assertEquals("<root attr=\"value\"></root>",
+                writeWithAttribute(null, null, attr));
+    }
+
+    // Writes attribute via writeUsing() on a Stax2-wrapped JDK stream writer
+    private static String writeWithAttribute(String nsPrefix, String nsURI,
+            AttributeEventImpl attr)
+        throws XMLStreamException
+    {
+        StringWriter out = new StringWriter();
+        XMLStreamWriter2 w = Stax2WriterAdapter.wrapIfNecessary(
+                XMLOutputFactory.newInstance().createXMLStreamWriter(out));
+        w.writeStartElement("root");
+        if (nsPrefix != null) {
+            w.writeNamespace(nsPrefix, nsURI);
+        }
+        attr.writeUsing(w);
+        w.writeEndElement();
+        w.close();
+        return out.toString();
+    }
+}