Add XmlUtil.prettyFormatXml()

smack-core/src/main/java/org/jivesoftware/smack/util/XmlUtil.java

@@ -0,0 +1,62 @@
+/**
+ *
+ * Copyright 2017 Florian Schmaus.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.util;
+
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import javax.xml.transform.OutputKeys;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.stream.StreamResult;
+import javax.xml.transform.stream.StreamSource;
+
+public class XmlUtil {
+
+    private static final Logger LOGGER = Logger.getLogger(XmlUtil.class.getName());
+
+    private static final TransformerFactory transformerFactory = TransformerFactory.newInstance();
+
+    static {
+        transformerFactory.setAttribute("indent-number", 2);
+    }
+
+    public static String prettyFormatXml(String xml) {
+        StreamSource source = new StreamSource(new StringReader(xml));
+        StringWriter stringWriter = new StringWriter();
+        StreamResult result = new StreamResult(stringWriter);
+
+        try {
+            Transformer transformer = transformerFactory.newTransformer();
+            transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
+            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+            transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
+
+            // Transform the requested string into a nice formatted XML string
+            transformer.transform(source, result);
+        }
+        catch (TransformerException | IllegalArgumentException e) {
+            LOGGER.log(Level.SEVERE, "Transformer error", e);
+            return xml;
+        }
+
+        return stringWriter.toString();
+    }
+}

smack-core/src/test/java/org/jivesoftware/smack/util/XmlUtilTest.java

@@ -0,0 +1,44 @@
+/**
+ *
+ * Copyright 2017 Florian Schmaus.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.util;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class XmlUtilTest {
+
+    @Test
+    public void prettyFormatXmlTest() {
+        final String uglyXml = "<foo attr1='value1' attr2='value2'><inner-element attr1='value1'>Test</inner-element></foo>";
+
+        final String prettyXml = XmlUtil.prettyFormatXml(uglyXml);
+
+        assertEquals("<foo attr1=\"value1\" attr2=\"value2\">\n  <inner-element attr1=\"value1\">Test</inner-element>\n</foo>\n",
+                        prettyXml);
+    }
+
+    @Test
+    public void prettyFormatIncompleteXmlTest() {
+        final String uglyXml = "<foo attr1='value1' attr2='value2'><inner-element attr1='value1'>Test</inner-element>";
+
+        final String prettyXml = XmlUtil.prettyFormatXml(uglyXml);
+
+        assertEquals("<foo attr1='value1' attr2='value2'><inner-element attr1='value1'>Test</inner-element>",
+                        prettyXml);
+    }
+}