From 591f71d079603d4deeef3b5742ab5e609906483d Mon Sep 17 00:00:00 2001
From: Rodrigo Queiro <rodrigoq@google.com>
Date: Wed, 14 Feb 2018 15:49:56 +0100
Subject: [PATCH] simtime: use time=0 by default
This is the behaviour documented here:
http://wiki.ros.org/Clock#Using_Simulation_Time_from_the_.2BAC8-clock_Topic
If the /use_sim_time parameter is set, the ROS Time API will return
time=0 until it has received a value from the /clock topic. Then,
the time will only be updated on receipt of a message from the
/clock topic, and will stay constant between updates.
This resolves a NullPointerException when a node logs from its onStart
method and use_sim_time is true.
---
.../src/main/java/org/ros/time/ClockTopicTimeProvider.java | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/rosjava/src/main/java/org/ros/time/ClockTopicTimeProvider.java b/rosjava/src/main/java/org/ros/time/ClockTopicTimeProvider.java
index 4e52dd35..22d4e324 100644
--- a/rosjava/src/main/java/org/ros/time/ClockTopicTimeProvider.java
+++ b/rosjava/src/main/java/org/ros/time/ClockTopicTimeProvider.java
@@ -57,7 +57,12 @@ public class ClockTopicTimeProvider implements TimeProvider {
@Override
public Time getCurrentTime() {
- Preconditions.checkNotNull(clock);
+ // When using simulation time, the ROS Time API will return time=0 until it has received a
+ // message from the /clock topic.
+ if (clock == null) {
+ return new Time();
+ }
+
synchronized (mutex) {
return new Time(clock.getClock());
}
--
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