DATACMNS-486 - Added ParsingUtils helper class to easily transform camel case Strings.

Refactored XmlRepositoryConfigurationSource to use the newly introduced type.

src/main/java/org/springframework/data/repository/config/XmlRepositoryConfigurationSource.java

@@ -15,11 +15,7 @@
  */
 package org.springframework.data.repository.config;
 
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.List;
-import java.util.Locale;
-import java.util.regex.Pattern;
 
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.core.env.Environment;
@@ -27,6 +23,7 @@ import org.springframework.core.type.filter.TypeFilter;
 import org.springframework.data.config.TypeFilterParser;
 import org.springframework.data.config.TypeFilterParser.Type;
 import org.springframework.data.repository.query.QueryLookupStrategy;
+import org.springframework.data.util.ParsingUtils;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.w3c.dom.Element;
@@ -46,8 +43,6 @@ public class XmlRepositoryConfigurationSource extends RepositoryConfigurationSou
 	private static final String REPOSITORY_FACTORY_BEAN_CLASS_NAME = "factory-class";
 	private static final String CONSIDER_NESTED_REPOSITORIES = "consider-nested-repositories";
 
-	private static final Pattern CAMEL_CASE_PARTS = Pattern.compile("(?<!(^|[A-Z]))(?=[A-Z])|(?<!^)(?=[A-Z][a-z])");
-
 	private final Element element;
 	private final ParserContext context;
 
@@ -175,13 +170,7 @@ public class XmlRepositoryConfigurationSource extends RepositoryConfigurationSou
 	@Override
 	public String getAttribute(String name) {
 
-		List<String> lowercase = new ArrayList<String>();
-
-		for (String part : Arrays.asList(CAMEL_CASE_PARTS.split(name))) {
-			lowercase.add(part.toLowerCase(Locale.US));
-		}
-
-		String xmlAttributeName = StringUtils.collectionToDelimitedString(lowercase, "-");
+		String xmlAttributeName = ParsingUtils.reconcatenateCamelCase(name, "-");
 		String attribute = element.getAttribute(xmlAttributeName);
 
 		return StringUtils.hasText(attribute) ? attribute : null;

src/main/java/org/springframework/data/util/ParsingUtils.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2014 the original author or authors.
+ *
+ * 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.springframework.data.util;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Pattern;
+
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Utility methods for {@link String} parsing.
+ * 
+ * @author Oliver Gierke
+ * @since 1.5
+ */
+public abstract class ParsingUtils {
+
+	private static final String UPPER = "\\p{Lu}|\\P{InBASIC_LATIN}";
+	private static final String LOWER = "\\p{Ll}";
+	private static final String CAMEL_CASE_REGEX = "(?<!(^|[%u_$]))(?=[%u])|(?<!^)(?=[%u][%l])". //
+			replace("%u", UPPER).replace("%l", LOWER);
+
+	private static final Pattern CAMEL_CASE = Pattern.compile(CAMEL_CASE_REGEX);
+
+	private ParsingUtils() {}
+
+	/**
+	 * Splits up the given camel-case {@link String}.
+	 * 
+	 * @param source must not be {@literal null}.
+	 * @return
+	 */
+	public static List<String> splitCamelCase(String source) {
+		return split(source, false);
+	}
+
+	/**
+	 * Splits up the given camel-case {@link String} and returns the parts in lower case.
+	 * 
+	 * @param source must not be {@literal null}.
+	 * @return
+	 */
+	public static List<String> splitCamelCaseToLower(String source) {
+		return split(source, true);
+	}
+
+	/**
+	 * Reconcatenates the given camel-case source {@link String} using the given delimiter. Will split up the camel-case
+	 * {@link String} and use an uncapitalized version of the parts.
+	 * 
+	 * @param source must not be {@literal null}.
+	 * @param delimiter must not be {@literal null}.
+	 * @return
+	 */
+	public static String reconcatenateCamelCase(String source, String delimiter) {
+
+		Assert.notNull(source, "Source string must not be null!");
+		Assert.notNull(delimiter, "Delimiter must not be null!");
+
+		return StringUtils.collectionToDelimitedString(splitCamelCaseToLower(source), delimiter);
+	}
+
+	private static List<String> split(String source, boolean toLower) {
+
+		Assert.notNull(source, "Source string must not be null!");
+
+		String[] parts = CAMEL_CASE.split(source);
+		List<String> result = new ArrayList<String>(parts.length);
+
+		for (String part : parts) {
+			result.add(toLower ? part.toLowerCase() : part);
+		}
+
+		return Collections.unmodifiableList(result);
+	}
+}