/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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.jboss.netty.util.internal;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.regex.Pattern;
  
  /**
   * Conversion utility class to parse a property represented as a string or
   * an object.
   */
  public final class ConversionUtil {
  
      /**
       * Converts the specified object into an integer.
       */
      public static int toInt(Object value) {
          if (value instanceof Number) {
              return ((Number) value).intValue();
          } else {
              return Integer.parseInt(String.valueOf(value));
          }
      }
  
      /**
       * Converts the specified object into a boolean.
       */
      public static boolean toBoolean(Object value) {
          if (value instanceof Boolean) {
              return ((Boolean) value).booleanValue();
          }
          if (value instanceof Number) {
              return ((Number) value).intValue() != 0;
          } else {
              String s = String.valueOf(value);
              if (s.length() == 0) {
                  return false;
              }
  
              try {
                  return Integer.parseInt(s) != 0;
              } catch (NumberFormatException e) {
                  // Proceed
              }
  
              switch (Character.toUpperCase(s.charAt(0))) {
              case 'T': case 'Y':
                  return true;
              }
              return false;
          }
      }
  
      private static final Pattern ARRAY_DELIM = Pattern.compile("[, \\t\\n\\r\\f\\e\\a]");
  
      /**
       * Converts the specified object into an array of strings.
       */
      public static String[] toStringArray(Object value) {
          if (value instanceof String[]) {
              return (String[]) value;
          }
  
          if (value instanceof Iterable<?>) {
              List<String> answer = new ArrayList<String>();
              for (Object v: (Iterable<?>) value) {
                  if (v == null) {
                      answer.add(null);
                  } else {
                      answer.add(String.valueOf(v));
                  }
              }
              return answer.toArray(new String[answer.size()]);
          }
  
          return ARRAY_DELIM.split(String.valueOf(value));
      }
  
      private static final String[] INTEGERS = {
          "0",  "1",  "2",  "3",  "4",  "5",  "6",  "7",  "8",  "9",
          "10", "11", "12", "13", "14", "15",
      };
  
      public static String toString(int value) {
          if (value >= 0 && value < INTEGERS.length) {
             return INTEGERS[value];
         } else {
             return Integer.toString(value);
         }
     }
 
     private ConversionUtil() {
         // Unused
     }
 }