From 7d7ffff8d7bda867cceb0f1150de515b8dbb6d46 Mon Sep 17 00:00:00 2001
From: Konstantinos Chatzilygeroudis <costashatz@gmail.com>
Date: Sat, 31 May 2014 02:04:27 +0300
Subject: [PATCH] Fixed typo in README and added checks in mimic plugin

---
 README.md                  |  2 +-
 src/mimic_joint_plugin.cpp | 24 +++++++++++++++++-------
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 7d0eb32..16f6d21 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ A simple (Model) plugin for Gazebo that allows you to disable a link in Gazebo's
 
     - link (Required)
 
-      A **string** specifying the name of the link to be disable. It should be a valid sdf (not urdf) link.
+      A **string** specifying the name of the link to be disabled. It should be a valid sdf (not urdf) link.
 
 ###Hoping to add more plugins....
 
diff --git a/src/mimic_joint_plugin.cpp b/src/mimic_joint_plugin.cpp
index f3aa770..979912f 100644
--- a/src/mimic_joint_plugin.cpp
+++ b/src/mimic_joint_plugin.cpp
@@ -45,7 +45,7 @@ void MimicJointPlugin::Load(physics::ModelPtr _parent, sdf::ElementPtr _sdf )
   this->world_ = this->model_->GetWorld();
 
   // Check for joint element
-  if (!_sdf->HasElement("joint"))
+  if(!_sdf->HasElement("joint"))
   {
     ROS_ERROR("No joint element present. MimicJointPlugin could not be loaded.");
     return;
@@ -54,7 +54,7 @@ void MimicJointPlugin::Load(physics::ModelPtr _parent, sdf::ElementPtr _sdf )
   joint_name_ = _sdf->GetElement("joint")->Get<std::string>();
 
   // Check for mimicJoint element
-  if (!_sdf->HasElement("mimicJoint"))
+  if(!_sdf->HasElement("mimicJoint"))
   {
     ROS_ERROR("No mimicJoint element present. MimicJointPlugin could not be loaded.");
     return;
@@ -64,7 +64,7 @@ void MimicJointPlugin::Load(physics::ModelPtr _parent, sdf::ElementPtr _sdf )
 
   // Check for multiplier element
   multiplier_ = 1.0;
-  if (_sdf->HasElement("multiplier"))
+  if(_sdf->HasElement("multiplier"))
     multiplier_ = _sdf->GetElement("multiplier")->Get<double>();
 
   // Check for offset element
@@ -72,14 +72,24 @@ void MimicJointPlugin::Load(physics::ModelPtr _parent, sdf::ElementPtr _sdf )
   if (_sdf->HasElement("offset"))
     offset_ = _sdf->GetElement("offset")->Get<double>();
 
+  // Get pointers to joints
+  joint_ = model_->GetJoint(joint_name_);
+  if(!joint_)
+  {
+    ROS_ERROR("No joint named %s. MimicJointPlugin could not be loaded.", joint_name_.c_str());
+    return;
+  }
+  mimic_joint_ = model_->GetJoint(mimic_joint_name_);
+  if(!mimic_joint_)
+  {
+    ROS_ERROR("No (mimic) joint named %s. MimicJointPlugin could not be loaded.", mimic_joint_name_.c_str());
+    return;
+  }
+
   // Listen to the update event. This event is broadcast every
   // simulation iteration.
   this->updateConnection = event::Events::ConnectWorldUpdateBegin(
       boost::bind(&MimicJointPlugin::UpdateChild, this));
-
-  // Get pointers to joints
-  joint_ = model_->GetJoint(joint_name_);
-  mimic_joint_ = model_->GetJoint(mimic_joint_name_);
 }
 
 void MimicJointPlugin::UpdateChild()
-- 
2.12.0