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/* $Id: NlsAccess.java 402 2008-01-14 21:09:00Z hohwille $
 * Copyright (c) The m-m-m Team, Licensed under the Apache License, Version 2.0
 * http://www.apache.org/licenses/LICENSE-2.0 */
package net.sf.mmm.util.nls;

import net.sf.mmm.util.nls.api.NlsMessageFactory;
import net.sf.mmm.util.nls.base.NlsMessageFactoryImpl;

/**
 * This is an ugly static accessor for the {@link NlsMessageFactory} used to
 * create instances of {@link net.sf.mmm.util.nls.api.NlsMessage} and allowing
 * to exchange the default implementation.
 * 
 * @author Joerg Hohwiller (hohwille at users.sourceforge.net)
 */
public final class NlsAccess {

  /** @see #getFactory() */
  private static NlsMessageFactory factory = new NlsMessageFactoryImpl();

  /**
   * The constructor.
   */
  private NlsAccess() {

    super();
  }

  /**
   * This method gets the {@link NlsMessageFactory} used to create instances of
   * {@link net.sf.mmm.util.nls.api.NlsMessage}.
   * 
   * @return the factory instance.
   */
  public static NlsMessageFactory getFactory() {

    return factory;
  }

  /**
   * This method sets (overrides) the {@link NlsMessageFactory}. This allows to
   * exchange the {@link NlsMessageFactory} and thereby the implementation of
   * {@link net.sf.mmm.util.nls.api.NlsMessage} e.g. to use a universal
   * {@link net.sf.mmm.util.nls.api.NlsTemplateResolver template-translator} for
   * {@link net.sf.mmm.util.nls.api.NlsMessage#getLocalizedMessage()} as used by
   * {@link net.sf.mmm.util.nls.api.NlsThrowable#getMessage()}.

   * The desired behaviour of a universal translator can depend from the
   * situation where it is used. E.g. a client application could use the
   * {@link java.util.Locale#getDefault() "default locale"} to choose the
   * destination language. In a multi-user server application a
   * {@link ThreadLocal} may be used to retrieve the appropriate
   * {@link java.util.Locale locale}.

   * WARNING:

   * This is only a back-door for simple applications or test situations. Please
   * try to avoid using this feature as well as
   * {@link net.sf.mmm.util.nls.api.NlsMessage#getLocalizedMessage()} and solve
   * this issue with IoC strategies (using non-final static fields like here is
   * evil).

   * ATTENTION:

   * No synchronization is performed setting the factory instance. This assumes
   * that an assignment is an atomic operation in the JVM you are using.
   * Additionally this method should only be invoked in the initialization phase
   * of your application.
   * 
   * @param instance the factory-instance to use.
   */
  public static void setFactory(NlsMessageFactory instance) {

    NlsAccess.factory = instance;
  }

}