Synchronize stuff in periodicscheduler and preferences

Author: James Hagborg

src/main/java/org/usfirst/frc/team69/util/PeriodicScheduler.java

@@ -8,6 +8,9 @@
  * one can add methods to report information to the driver station, or to
  * check if preferences have been changed.
  * 
+ * This class should be thread-safe, provided it is OK to run all events
+ * from the main thread.
+ * 
  * @author James Hagborg
  *
  */
@@ -20,7 +23,7 @@ public class PeriodicScheduler {
      * 
      * @return The sinlge instance of {@link PeriodicScheduler}
      */
-    public static PeriodicScheduler getInstance() {
+    public static synchronized PeriodicScheduler getInstance() {
         if (theInstance == null) {
             theInstance = new PeriodicScheduler();
         }
@@ -39,15 +42,15 @@ private PeriodicScheduler() {
      * 
      * @param event A {@link Runnable} object representing the task to run 
      */
-    public void addEvent(Runnable event) {
+    public synchronized void addEvent(Runnable event) {
         events.add(event);
     }
 
     /**
      * Run all of the events which have been added to the scheduler.  If you
      * are using {@link HYPERRobot}, you do not need to call this manually.
      */
-    public void run() {
+    public synchronized void run() {
         for (Runnable event : events) {
             event.run();
         }

src/main/java/org/usfirst/frc/team69/util/pref/PreferencesSet.java

@@ -27,6 +27,19 @@ public class PreferencesSet {
 
     private static HashSet<String> setNames = new HashSet<String>();
 
+    /**
+     * Check the set name does not exist and add it if it does.  This needs to
+     * be synchronized to access the global list.
+     * @param name The name to add and check
+     */
+    private synchronized static void registerSetName(String name) {
+        if (setNames.contains(name)) {
+            throw new IllegalStateException("A PreferencesSet named " + name + " already exists");
+        }
+        
+        setNames.add(name);
+    }
+    
     /**
      * Construct a new {@link PreferencesSet} object with the given name and
      * {@link PreferencesListener}.  Each time a preference in the set is
@@ -41,11 +54,9 @@ public PreferencesSet(String name, PreferencesListener listener) {
             throw new NullPointerException("name == null");
         } else if (listener == null) {
             throw new NullPointerException("listener == null");
-        } if (setNames.contains(name)) {
-            throw new IllegalStateException("A PreferencesSet named " + name + " already exists");
         }
 
-        setNames.add(name);
+        registerSetName(name);
 
         m_name = name;
         m_listener = listener;
@@ -108,7 +119,7 @@ private void addPreference(String name, Preference pref) {
      * @param value The default value
      * @return The newly created preference
      */
-    public DoublePreference addDouble(String name, double value) {
+    public synchronized DoublePreference addDouble(String name, double value) {
         checkName(name);
         DoublePreference pref = new DoublePreference(m_name + SEPARATOR + name, value);
         addPreference(name, pref);
@@ -122,7 +133,7 @@ public DoublePreference addDouble(String name, double value) {
      * @param value The default value
      * @return The newly created preference
      */
-    public IntPreference addInt(String name, int value) {
+    public synchronized IntPreference addInt(String name, int value) {
         checkName(name);
         IntPreference pref = new IntPreference(m_name + SEPARATOR + name, value);
         addPreference(name, pref);
@@ -136,7 +147,7 @@ public IntPreference addInt(String name, int value) {
      * @param value The default value
      * @return The newly created preference
      */
-    public BooleanPreference addBoolean(String name, boolean value) {
+    public synchronized BooleanPreference addBoolean(String name, boolean value) {
         checkName(name);
         BooleanPreference pref = new BooleanPreference(m_name + SEPARATOR + name, value);
         addPreference(name, pref);
@@ -150,7 +161,7 @@ public BooleanPreference addBoolean(String name, boolean value) {
      * @param value The default value
      * @return The newly created preference
      */
-    public StringPreference addString(String name, String value) {
+    public synchronized StringPreference addString(String name, String value) {
         checkName(name);
         StringPreference pref = new StringPreference(m_name + SEPARATOR + name, value);
         addPreference(name, pref);