public final static boolean isMailAddress(String str)
    {
        int atIndex = str.indexOf('@');
        if ( atIndex == -1 ) {
            return false;
        }
        
        if ( ! StringUtil.isLetterOrNumeric(str, 0, atIndex) ) {
            return false;
        }
        
        int ptIndex, ptStart = atIndex + 1;
        while ( (ptIndex = str.indexOf('.', ptStart)) > 0 ) {
            if ( ptIndex == ptStart ) {
                return false;
            }
            
            if ( ! StringUtil.isLetterOrNumeric(str, ptStart, ptIndex) ) {
                return false;
            }
            
            ptStart = ptIndex + 1;
        }
        
        if ( ptStart < str.length() 
                && ! StringUtil.isLetterOrNumeric(str, ptStart, str.length()) ) {
            return false;
        }
        
        return true;
    }
public final static boolean isMailAddress ( String str ) { int atIndex = str . indexOf ( '@' ) ; if ( atIndex == - 1 ) { return false ; } if ( ! StringUtil . isLetterOrNumeric ( str , 0 , atIndex ) ) { return false ; } int ptIndex , ptStart = atIndex + 1 ; while ( ( ptIndex = str . indexOf ( '.' , ptStart ) ) > 0 ) { if ( ptIndex == ptStart ) { return false ; } if ( ! StringUtil . isLetterOrNumeric ( str , ptStart , ptIndex ) ) { return false ; } ptStart = ptIndex + 1 ; } if ( ptStart < str . length ( ) && ! StringUtil . isLetterOrNumeric ( str , ptStart , str . length ( ) ) ) { return false ; } return true ; }
check if the specified string is an email address or not

@param   str
@return  boolean