/*

  *  Copyright 2003-2004 The Apache Software Foundation

  *

  *  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.apache.commons.convert1.array;

 import java.util.ArrayList;

 import java.util.List;

 import java.io.IOException;

 import java.io.StreamTokenizer;

 import java.io.StringReader;

 import org.apache.commons.convert1.ConversionException;

 /**

  * Temporary file containing the String to String[] 

  * parsing. 

  */

 public class StringArrayParser {

     // TODO: This needs to be extracted out so that the 

     //       parsing part is not tied to an incoming String. 

     /**

      * <p>Parse an incoming String of the form similar to an array initializer

      * in the Java language into a <code>List</code> individual Strings

      * for each element, according to the following rules.</p>

      * <ul>

      * <li>The string must have matching '{' and '}' delimiters around

      *     a comma-delimited list of values.</li>

      * <li>Whitespace before and after each element is stripped.

      * <li>If an element is itself delimited by matching single or double

      *     quotes, the usual rules for interpreting a quoted String apply.</li>

      * </ul>

      *

      * @param svalue String value to be parsed

      *

      * @exception ConversionException if the syntax of <code>svalue</code>

      *  is not syntactically valid

      * @exception NullPointerException if <code>svalue</code>

      *  is <code>null</code>

      */

     static List parseElements(String svalue) {

         // Validate the passed argument

         if (svalue == null) {

             throw new NullPointerException();

         }

         // Trim any matching '{' and '}' delimiters

         svalue = svalue.trim();

         if (svalue.startsWith("{") && svalue.endsWith("}")) {

             svalue = svalue.substring(1, svalue.length() - 1);

         }

         try {

             // Set up a StreamTokenizer on the characters in this String

             StreamTokenizer st =

                 new StreamTokenizer(new StringReader(svalue));

             st.whitespaceChars(',',','); // Commas are delimiters

             st.ordinaryChars('0', '9');  // Needed to turn off numeric flag

             st.ordinaryChars('.', '.');

             st.ordinaryChars('-', '-');

             st.wordChars('0', '9');      // Needed to make part of tokens

             st.wordChars('.', '.');

             st.wordChars('-', '-');

             // Split comma-delimited tokens into a List

             ArrayList list = new ArrayList();

             while (true) {

                 int ttype = st.nextToken();

                 if ((ttype == StreamTokenizer.TT_WORD) ||

                     (ttype > 0)) {

                     list.add(st.sval);

                 } else if (ttype == StreamTokenizer.TT_EOF) {

                     break;

                 } else {

                     throw new ConversionException

                         ("Encountered token of type " + ttype);

                 }

             }

             // Return the completed list

             return (list);

         } catch (IOException e) {

             throw new ConversionException(e);

         }

     }

 }