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uid: Lucene.Net.QueryParsers.Flexible.Messages summary: *content

For Native Language Support (NLS), system of software internationalization.

NLS message API

This utility API, adds support for NLS messages in the apache code. It is currently used by the lucene “New Flexible Query PArser”.

Features:

1. Message reference in the code, using static Strings
2. Message resource validation at class load time, for easier debugging
3. Allows for message IDs to be re-factored using code re-factor tools
4. Allows for reference count on messages, just like code
5. Lazy loading of Message Strings
6. Normal loading Message Strings

Prerequisite for these examples: Add a resource file named MessagesTestBundle.resx and add messages for each of the public static string fields except for Q0005E_Message_Not_In_Bundle.

Lazy loading of Message Strings

public class MessagesTest : NLS
{
    private static readonly string BundleName = typeof(MessagesTest).FullName;

    private MessagesTest()
    {
        // should never be instantiated
    }

    static MessagesTest()
    {
        InitializeMessages(BundleName, typeof(MessagesTest));
    }

    // static string must match the strings in the property files.
    public static string Q0001E_Invalid_Syntax;
    public static string Q0004E_Invalid_Syntax_Escape_Unicode_Truncation;

    // this message is missing from the properties file
    public static string Q0005E_Message_Not_In_Bundle;
}

// Create a message reference
IMessage invalidSyntax = new Message(MessagesTest.Q0001E_Invalid_Syntax, "XXX");

// Do other stuff in the code...
// when is time to display the message to the user or log the message on a file
// the message is loaded from the correct bundle

string message1 = invalidSyntax.GetLocalizedMessage();
string message2 = invalidSyntax.GetLocalizedMessage(new CultureInfo("ja"));

Normal loading of Message Strings

string message1 = NLS.GetLocalizedMessage(MessagesTest.Q0004E_Invalid_Syntax_Escape_Unicode_Truncation);
string message2 = NLS.GetLocalizedMessage(MessagesTest.Q0004E_Invalid_Syntax_Escape_Unicode_Truncation, new CultureInfo("ja"));

The Lucene.Net.QueryParsers.Flexible.Messages.TestNLS NUnit test contains several other examples. The TestNLS C# code is available from the Apache Lucene.NET code repository.