7.3 Building a Message Catalog

Message catalogs for each supported language are stored in the locale directory (Section 7.2), under their respective locale names. For example:

RWSF_HOME/
   conf/
      locale/
         en_US/
            messages_core_en_US.xml
            messages_agent_en_US.xml
         fr_FR/
            messages_core_fr_FR.xml
            messages_agent_fr_FR.xml
         ...

Note that there are multiple files per locale -- one for each HydraExpress component.

Each message catalog consists of a simple XML document containing a collection of localized strings. For example:

<messages xmlns="http://www.roguewave.com/rwsf/messages">
  <catalog locality="en_US" component="RWSF_CORE">
    <entry name="INVALID_BASE64">
      <message>Invalid base64 encoded character</message>
    </entry>
    <entry name="UNEXPECTED_ERROR">
      <message>Unexpected Exception</message>
    </entry>
  </catalog>
</messages>

When a message catalog is loaded, each message identifier is converted into a constant variable named <component>_<messageIdentifier>. For example, the catalog sample above creates constant variables RWSF_CORE_INVALID_BASE64 and RWSF_CORE_UNEXPECTED ERROR. You can use these variables when constructing localized strings (Section 7.4) to get compile time checks against typographical errors.

---

The identifier strings must only contain characters consistent with C++ identifiers [A-Za-z0-9_]. These strings should not be localized, and instead are used as keys for locating the localized message strings.

---

The message format also supports inserting dynamic content into messages. A %-delimited string is used to identify where named substitutions can occur. For example:

<messages xmlns="http://www.roguewave.com/rwsf/messages">
  <catalog locality="en_US" component="RWSF_CORE">
    <entry name="ILLEGAL_INDEX">
      <message>Index (%1%) out of range [0->%2%]</message>
    </entry>
  </catalog>
</messages>

When constructing a rwsf::LocalizedMessage to represent this message (Section 7.4), you can specify the values that should be associated with %1% and %2%. Note that since this mechanism uses numbered substitutions, you are free to re-order the substitution elements in localized strings. For instance:

<message>In range [0->%2%], %1% is invalid</message>

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