Parameter Node added to new Helper module.

rosjava_helpers/build.gradle

+apply plugin: 'java'
+
+dependencies {
+    compile project(':rosjava')
+    compile 'org.yaml:snakeyaml:[1.17, 1.18)'
+}
\ No newline at end of file

rosjava_helpers/src/main/java/org/ros/helpers/ParameterLoaderNode.java

+/*
+ * Copyright 2017 Ekumen, Inc. All Rights Reserved.
+ *
+ * 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 org.ros.helpers;
+
+import org.apache.commons.logging.Log;
+import org.ros.namespace.GraphName;
+import org.ros.node.AbstractNodeMain;
+import org.ros.node.ConnectedNode;
+import org.ros.node.parameter.ParameterTree;
+import org.yaml.snakeyaml.Yaml;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Loads parameters from Yaml files into the ROS parameter server.
+ * A different namespace can be specified for each of the files to load.
+ * To use this node, create a {@link Resource} list with the resources to load,
+ * and start it in the standard RosJava way.
+ *
+ * @author lucas@ekumenlabs.com (Lucas Chiesa).
+ * Modified by jubeira@ekumenlabs.com (Juan I. Ubeira)
+ */
+public class ParameterLoaderNode extends AbstractNodeMain {
+
+    public static final String NODE_NAME = "parameter_loader";
+    private final List<LoadedResource> params = new ArrayList<>();
+    private Log log;
+
+    /**
+     * Default constructor
+     * @param resources Array of resources with their respective namespace to load.
+     */
+    public ParameterLoaderNode(ArrayList<Resource> resources) {
+        for (Resource r : resources) {
+            addSingleYmlInput(r.inputStream, r.namespace == null ? "" : r.namespace);
+        }
+    }
+
+    private void addSingleYmlInput(InputStream ymlInputStream, String namespace) {
+        this.params.add(new LoadedResource((new Yaml()).load(ymlInputStream), namespace));
+    }
+
+    private void addParams(ParameterTree parameterTree, String namespace, Map<String, Object> params) {
+        for (Map.Entry<String, Object> e : params.entrySet()) {
+            String fullKeyName = namespace + "/" + e.getKey();
+            if (log != null) {
+                log.info("Loading parameter " + fullKeyName + " \nValue = " + e.getValue());
+            }
+
+            if (e.getValue() instanceof String) {
+                parameterTree.set(fullKeyName, (String)e.getValue());
+            } else if (e.getValue() instanceof Integer) {
+                parameterTree.set(fullKeyName, (Integer)e.getValue());
+            } else if (e.getValue() instanceof Double) {
+                parameterTree.set(fullKeyName, (Double)e.getValue());
+            } else if (e.getValue() instanceof Map) {
+                parameterTree.set(fullKeyName, (Map)e.getValue());
+            } else if (e.getValue() instanceof Boolean) {
+                parameterTree.set(fullKeyName, (Boolean)e.getValue());
+            } else if (e.getValue() instanceof List) {
+                parameterTree.set(fullKeyName, (List)e.getValue());
+            } else if (log != null) {
+                log.debug("I don't know what type parameter " + fullKeyName + " is. Value = " + e.getValue());
+                log.debug("Class name is: " + e.getValue().getClass().getName());
+            }
+        }
+    }
+
+    /**
+     * @return the name of the Node that will be used if a name was not
+     * specified in the Node's associated NodeConfiguration.
+     */
+    @Override
+    public GraphName getDefaultNodeName() {
+        return GraphName.of(NODE_NAME);
+    }
+
+    @Override
+    public void onStart(ConnectedNode connectedNode) {
+        if (params != null) {
+            ParameterTree parameterTree = connectedNode.getParameterTree();
+            log = connectedNode.getLog();
+
+            // TODO: For some reason, setting the / param when using a rosjava master doesn't work
+            // It does work fine with an external master, and also setting other params of any type
+            for (LoadedResource r : params) {
+                addParams(parameterTree, r.namespace, r.resource);
+            }
+
+            connectedNode.shutdown();
+        }
+    }
+
+    /**
+     * Resource to load to Parameter Server, consisting of an InputStream and its corresponding namespace.
+     */
+    public static class Resource {
+        public InputStream inputStream;
+        public String namespace;
+
+        public Resource(InputStream inputStream, String namespace) {
+            this.inputStream = inputStream;
+            this.namespace = namespace;
+        }
+    }
+
+    /**
+     * Thin wrapper for the object returned by Yaml.load().
+     * The object returned by Yaml.load() is a LinkedHashMap<String, Object>; this class is to
+     * keep the code simple.
+     */
+    private class LoadedResource {
+        public Map<String, Object> resource;
+        public String namespace;
+
+        LoadedResource(Object resource, String namespace) {
+            this.resource = (Map<String, Object>) resource;
+            this.namespace = namespace;
+        }
+    }
+}

settings.gradle

@@ -22,6 +22,7 @@ include(
     'rosjava_geometry',
     'rosjava_benchmarks',
     'rosjava_test',
+    'rosjava_helpers',
     'rosjava_tutorial_pubsub',
     'rosjava_tutorial_right_hand_rule',
     'rosjava_tutorial_services',