package com.simpligility.maven.plugins.android.configuration;
   
   import static java.lang.String.format;
   
   import java.util.regex.Matcher;
   import java.util.regex.Pattern;
   
   import org.apache.maven.plugin.MojoExecutionException;
   
  /**
   * Regex-based VersionElementParser implementation.
   *
   * @author Wang Xuerui idontknw.wang@gmail.com
   *
   */
  public class RegexVersionElementParser implements VersionElementParser
  {
  
      private Pattern namingPattern;
  
      public RegexVersionElementParser( String pattern )
      {
          namingPattern = Pattern.compile( pattern );
      }
  
      @Override
      public int[] parseVersionElements( final String versionName ) throws MojoExecutionException
      {
          final Matcher matcher = namingPattern.matcher( versionName );
          if ( ! matcher.find() )
          {
              throw new MojoExecutionException( format(
                      "The version naming pattern failed to match version name: %s against %s",
                      namingPattern, versionName ) );
          }
  
          int elementCount = matcher.groupCount();
          int[] result = new int[elementCount];
  
          for ( int i = 0; i < elementCount; i++ )
          {
              // Capturing groups start at index 1
              try
              {
                  result[i] = Integer.valueOf( matcher.group( i + 1 ) );
              }
              catch ( NumberFormatException ignored )
              {
                  // Either the group is not present, or cannot be cast to integer.
                  result[i] = 0;
              }
          }
  
          return result;
      }
  }