Fix after review

Author: slawekjaranowski

src/main/java/org/codehaus/plexus/util/xml/PrettyPrintXMLWriter.java

@@ -24,9 +24,9 @@
 import java.util.regex.Pattern;
 
 /**
- * Implementation of XMLWriter which emits nicely formatted documents.
- *
+ * <p>Implementation of XMLWriter which emits nicely formatted documents.</p>
  *
+ * <p>C0 controls chars are omitted from output</p>
  */
 public class PrettyPrintXMLWriter implements XMLWriter {
     /** Line separator ("\n" on UNIX) */
@@ -226,9 +226,9 @@ private static String escapeXml(String text) {
 
     private static final Pattern crlf = Pattern.compile(crlf_str);
 
-    private static final Pattern lowers = Pattern.compile("([\000-\037])");
+    private static final Pattern lowers = Pattern.compile("([\\x00-\\x1F])");
 
-    private static final Pattern lowersText = Pattern.compile("([\000-\010\013-\014\016-\037])");
+    private static final Pattern illegalC0Characters = Pattern.compile("([\\x00-\\x08\\x0B-\\x0C\\x0E-\\x1F])");
 
     private static String escapeXmlAttribute(String text) {
         text = escapeXmlText(text);
@@ -252,12 +252,12 @@ private static String escapeXmlAttribute(String text) {
     private static String escapeXmlText(String text) {
         text = escapeXml(text);
 
-        Matcher m = lowersText.matcher(text);
+        Matcher matcher = illegalC0Characters.matcher(text);
         StringBuffer b = new StringBuffer();
-        while (m.find()) {
-            m = m.appendReplacement(b, "");
+        while (matcher.find()) {
+            matcher = matcher.appendReplacement(b, "");
         }
-        m.appendTail(b);
+        matcher.appendTail(b);
 
         return b.toString();
     }

src/main/java/org/codehaus/plexus/util/xml/pull/MXSerializer.java

@@ -24,6 +24,7 @@
  * <li>PROPERTY_SERIALIZER_INDENTATION
  * <li>PROPERTY_SERIALIZER_LINE_SEPARATOR
  * </ul>
+ * <p>C0 controls chars are omitted from output</p>
  */
 public class MXSerializer implements XmlSerializer {
     protected static final String XML_URI = "http://www.w3.org/XML/1998/namespace";

src/test/java/org/codehaus/plexus/util/xml/pull/MXSerializerTest.java

@@ -47,11 +47,11 @@ private String expectedOutput() {
         out.append("<?xml version=\"1.0\" standalone=\"yes\"?>");
         out.append("<root>");
         out.append("<char>BACKSPACE: </char>");
-        out.append("<char>CHARACTER TABULATION: \t");
-        out.append("</char><char>LINE FEED (LF): \n");
-        out.append("</char><char>LINE TABULATION: </char>");
-        out.append("<char>CARRIAGE RETURN (CR): \r");
-        out.append("</char><char>SHIFT IN: </char>");
+        out.append("<char>CHARACTER TABULATION: \t</char>");
+        out.append("<char>LINE FEED (LF): \n</char>");
+        out.append("<char>LINE TABULATION: </char>");
+        out.append("<char>CARRIAGE RETURN (CR): \r</char>");
+        out.append("<char>SHIFT IN: </char>");
         out.append("</root>");
         return out.toString();
     }