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1 # Software License Agreement (BSD License) 2 # 3 # Copyright (c) 2009, Willow Garage, Inc. 4 # All rights reserved. 5 # 6 # Redistribution and use in source and binary forms, with or without 7 # modification, are permitted provided that the following conditions 8 # are met: 9 # 10 # * Redistributions of source code must retain the above copyright 11 # notice, this list of conditions and the following disclaimer. 12 # * Redistributions in binary form must reproduce the above 13 # copyright notice, this list of conditions and the following 14 # disclaimer in the documentation and/or other materials provided 15 # with the distribution. 16 # * Neither the name of Willow Garage, Inc. nor the names of its 17 # contributors may be used to endorse or promote products derived 18 # from this software without specific prior written permission. 19 # 20 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 28 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 30 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 # POSSIBILITY OF SUCH DAMAGE. 32 33 """Parameter Server Cache""" 34 35 36 import threading 37 38 #TODO: get rid of this routine entirely. It doesn't work with the current PS representation.40 """ 41 Cache of values on the parameter server. Implementation 42 is just a thread-safe dictionary. 43 """ 44 49 50 ## Delete parameter from cache 54107 108 _param_server_cache = None56 """ 57 Notifier implements any parameter subscription logic. The 58 notifier should be a function that takes in a key and value 59 that represents a parameter update. Notifier is called under 60 lock and thus must not implement any lengthy computation. 61 """ 62 self.notifier = notifier6365 """ 66 Update the value of the parameter in the cache 67 @param key: parameter key 68 @type key: str 69 @param value: parameter value 70 @type value: str 71 @raise: KeyError if key is not already in the cache. 72 """ 73 # TODOXXX: remove this code, as it is wrong. It is remaining 74 # in place to maintain a unit test until the correct logic is 75 # implemented. update() needs to check all subscribed keys and 76 # do a prefix match. The best way to do this is probably to 77 # pull the paramserver implementation from rosmaster and use 78 # it here. 79 if not key in self.d: 80 raise KeyError(key) 81 with self.lock: 82 self.d[key] = value 83 if self.notifier is not None: 84 self.notifier(key, value)8587 """ 88 Set the value of the parameter in the cache. This is a 89 prerequisite of calling update(). 90 @param key: parameter key 91 @type key: str 92 @param value: parameter value 93 @type value: str 94 """ 95 with self.lock: 96 self.d[key] = value97110 """ 111 Get a handle on the client-wide parameter server cache 112 """ 113 global _param_server_cache 114 if _param_server_cache is None: 115 _param_server_cache = ParamServerCache() 116 return _param_server_cache117
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