Character Encoding in Messages

Character encodings are named sets of numeric values for representing characters. For example, ISO 8859-1, also known as Latin-1, is the character encoding containing the letters and symbols used by most Western European languages.

If your applications are sending and receiving messages that use only English language characters (that is, the ASCII character set), you do not need to alter your programs to handle different character encodings. The EMS server and application APIs automatically handle ASCII characters in messages.

Character sets become important when your application is handling messages that use non-ASCII characters (such as the Japanese language). Also, clients encode messages by default as UTF-8. Some character encodings use only one byte to represent each character, but UTF-8 can potentially use between one and four bytes to represent the same character. For example, the Latin-1 is a single-byte character encoding. If all strings in your messages contain only characters that appear in the Latin-1 encoding, you can potentially improve performance by specifying Latin-1 as the encoding for strings in the message.

EMS clients can specify a variety of common character encodings for strings in messages. The character encoding for a message applies to strings that appear in any of the following places within a message:

  • property names and property values
  • MapMessage field names and values
  • data within the message body

The EMS client APIs (Java, .NET and C) include mechanisms for handling strings and specifying the character encoding used for all strings within a message. The following sections describe the implications of string character encoding for EMS clients.

Note: Nearly all character sets include unprintable characters. EMS software does not prevent programs from using unprintable characters. However, messages containing unprintable characters (whether in headers or data) can cause unpredictable results if you instruct EMS to print them. For example, if you enable the message tracing feature, EMS prints messages to a trace log file.