content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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.apache.causeway.commons.internal.base;
  
  import java.util.StringTokenizer;
  import java.util.function.UnaryOperator;
  
  import org.jspecify.annotations.Nullable;
  
  import lombok.experimental.UtilityClass;
  
  /**
   * package private utility for {@link _Strings}
   */
  @UtilityClass
  class _Strings_CamelCase {
  
      /**
       * Camel case is the practice of writing phrases without spaces or punctuation and with capitalized words.
       * The format indicates the first word starting with EITHER case,
       * then the following words having an initial uppercase letter.
       */
      @Nullable
      String camelCase(final @Nullable String input, final UnaryOperator<String> firstTokenMapper) {
  
          if(input==null) return null;
          if(input.length()==0) return input;
  
          var sb = new StringBuffer(input.length());
          var tokenizer = new StringTokenizer(input, " \t\n\r\f._,:;");
          int tokenCount = 0;
  
          while (tokenizer.hasMoreTokens()) {
              final String token = tokenizer.nextToken();
              ++tokenCount;
  
              if(tokenCount==1) {
                  // convert first token/word using firstTokenMapper
                  sb.append(firstTokenMapper.apply(token));
              } else {
                  // convert token/word to capitalized
                  sb.append(token.substring(0, 1).toUpperCase());
                  sb.append(token.substring(1));
              }
          }
          return sb.toString();
      }
  }
  