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00001 #!/usr/bin/env python 00002 # Software License Agreement (BSD License) 00003 # 00004 # Copyright (c) 2008, Willow Garage, Inc. 00005 # All rights reserved. 00006 # 00007 # Redistribution and use in source and binary forms, with or without 00008 # modification, are permitted provided that the following conditions 00009 # are met: 00010 # 00011 # * Redistributions of source code must retain the above copyright 00012 # notice, this list of conditions and the following disclaimer. 00013 # * Redistributions in binary form must reproduce the above 00014 # copyright notice, this list of conditions and the following 00015 # disclaimer in the documentation and/or other materials provided 00016 # with the distribution. 00017 # * Neither the name of Willow Garage, Inc. nor the names of its 00018 # contributors may be used to endorse or promote products derived 00019 # from this software without specific prior written permission. 00020 # 00021 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 00022 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00023 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00024 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 00025 # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00026 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00027 # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 00028 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 00029 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00030 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 00031 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 00032 # POSSIBILITY OF SUCH DAMAGE. 00033 # 00034 # Revision $Id$ 00035 00036 ## talker that receives notification of new subscriptions 00037 00038 PKG = 'rospy_tutorials' # this package name 00039 NAME = 'talker_callback' 00040 00041 import roslib; roslib.load_manifest(PKG) 00042 00043 import sys 00044 00045 import rospy 00046 from std_msgs.msg import String 00047 00048 class ChatterListener(rospy.SubscribeListener): 00049 def peer_subscribe(self, topic_name, topic_publish, peer_publish): 00050 print "a peer subscribed to topic [%s]"%topic_name 00051 00052 str = "Hey everyone, we have a new friend!" 00053 print str 00054 topic_publish(String(str)) 00055 str = "greetings. welcome to topic "+topic_name 00056 print str 00057 peer_publish(String(str)) 00058 00059 def peer_unsubscribe(self, topic_name, numPeers): 00060 print "a peer unsubscribed from topic [%s]"%topic_name 00061 if numPeers == 0: 00062 print "I have no friends" 00063 00064 def talker_callback(): 00065 pub = rospy.Publisher("chatter", String, ChatterListener()) 00066 rospy.init_node(NAME, anonymous=True) 00067 count = 0 00068 while not rospy.is_shutdown(): 00069 str = "hello world %d"%count 00070 print str 00071 pub.publish(String(str)) 00072 count += 1 00073 rospy.sleep(0.1) 00074 00075 if __name__ == '__main__': 00076 try: 00077 talker_callback() 00078 except rospy.ROSInterruptException: pass