PDFBOX-5660: optimize, as suggested by Valery Bokov; closes #346

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1929996 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/interactive/form/AppearanceGeneratorHelper.java

@@ -24,6 +24,7 @@
 import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.regex.Pattern;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
 import org.apache.fontbox.util.BoundingBox;
@@ -68,6 +69,8 @@ class AppearanceGeneratorHelper
 
     private static final Operator BMC = Operator.getOperator("BMC");
     private static final Operator EMC = Operator.getOperator("EMC");
+
+    private static final Pattern PATTERN = Pattern.compile("\\u000D\\u000A|[\\u000A\\u000B\\u000C\\u000D\\u0085\\u2028\\u2029]");
 
     private final PDVariableText field;
 
@@ -196,7 +199,7 @@ public void setAppearanceValue(String apValue) throws IOException
         // see PDFBOX-3911
         if (field instanceof PDTextField && !((PDTextField) field).isMultiline())
         {
-            value = value.replaceAll("\\u000D\\u000A|[\\u000A\\u000B\\u000C\\u000D\\u0085\\u2028\\u2029]", " ");
+            value = PATTERN.matcher(value).replaceAll(" ");
         }
 
         for (PDAnnotationWidget widget : field.getWidgets())