Merge devel code into the trunk.

[tinyos-2.x.git] / tos / lib / net / DisseminationUpdate.nc

diff --git a/tos/lib/net/DisseminationUpdate.nc b/tos/lib/net/DisseminationUpdate.nc
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+// $Id$
+/*
+ * "Copyright (c) 2006 Stanford University. All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and
+ * its documentation for any purpose, without fee, and without written
+ * agreement is hereby granted, provided that the above copyright
+ * notice, the following two paragraphs and the author appear in all
+ * copies of this software.
+ * 
+ * IN NO EVENT SHALL STANFORD UNIVERSITY BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF STANFORD UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ * 
+ * STANFORD UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE
+ * PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND STANFORD UNIVERSITY
+ * HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
+ * ENHANCEMENTS, OR MODIFICATIONS."
+ */
+
+/**
+ * Update a network shared (disseminated) value. Updates are assured
+ * to be eventually consistent across a connected network. If multiple
+ * nodes update a value simultaneously, then nodes within the network
+ * will see a series of one or more updates, the last update will
+ * be the same for all nodes. Components that need to use the
+ * variable should use the DisseminationValue interface.
+ *
+ * @author Philip Levis
+ * @author Gilman Tolle
+ * @date   January 7 2006
+ */ 
+
+
+
+interface DisseminationUpdate<t> {
+  /**
+   * Update the variable to a new value. This changes the local copy
+   * and begins to disseminate the new value throughout the network.
+   * As other nodes may have also changed the variable, it is possible
+   * that an update may not 'stick,' but will instead be overwritten by
+   * a separate update.
+   *
+   * @param newVal A pointer to the new value. The memory pointed to
+   * by newVal is copied out, so newVal can be reclaimed when
+   * <tt>change</tt> returns.
+   */
+  command void change(t* newVal);
+}