Added feedback message class.

Encapsulates the needed reflection methods.

src/rosjava_actionlib/rosjava_actionlib/src/main/java/com/github/ekumen/rosjava_actionlib/ActionFeedback.java

+/**
+ * Copyright 2015 Ekumen www.ekumenlabs.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.github.ekumen.rosjava_actionlib;
+
+import java.lang.reflect.Method;
+import org.ros.internal.message.Message;
+import org.ros.message.Time;
+import std_msgs.Header;
+import actionlib_msgs.GoalID;
+import actionlib_msgs.GoalStatus;
+
+/**
+ * Class to encapsulate the action feedback object.
+ * @author Ernesto Corbellini ecorbellini@ekumenlabs.com
+ */
+public class ActionFeedback<T_ACTION_FEEDBACK extends Message> {
+  private T_ACTION_FEEDBACK actionFeedbackMessage = null;
+
+  public ActionFeedback(T_ACTION_FEEDBACK fmsg) {
+    actionFeedbackMessage = fmsg;
+  }
+
+  public Header getHeaderMessage() {
+    Header h = null;
+    if (actionFeedbackMessage != null) {
+      try {
+        Method m = actionFeedbackMessage.getClass().getMethod("getHeader");
+        m.setAccessible(true); // workaround for known bug http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6924232
+        h = (Header)m.invoke(actionFeedbackMessage);
+      }
+      catch (Exception e) {
+        e.printStackTrace(System.out);
+      }
+    }
+    return h;
+  }
+
+  public GoalStatus getGoalStatusMessage() {
+    GoalStatus gs = null;
+    if (actionFeedbackMessage != null) {
+      try {
+        Method m = actionFeedbackMessage.getClass().getMethod("getStatus");
+        m.setAccessible(true); // workaround for known bug http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6924232
+        gs = (GoalStatus)m.invoke(actionFeedbackMessage);
+      }
+      catch (Exception e) {
+        e.printStackTrace(System.out);
+      }
+    }
+    return gs;
+  }
+
+  public Message getFeedbackMessage() {
+    Message x = null;
+    if (actionFeedbackMessage != null) {
+      try {
+        Method m = actionFeedbackMessage.getClass().getMethod("getFeedback");
+        m.setAccessible(true); // workaround for known bug http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6924232
+        x = (Message)m.invoke(actionFeedbackMessage);
+      }
+      catch (Exception e) {
+        e.printStackTrace(System.out);
+      }
+    }
+    return x;
+  }
+}