Introduced concurrency fixes as done in https://github.com/openhab/openhab/pull/3016

Signed-off-by: Kai Kreuzer <kai@openhab.org>

bundles/org.openhab.core.compat1x/src/main/java/org/openhab/model/item/binding/AbstractGenericBindingProvider.java

@@ -13,7 +13,6 @@ import java.util.Collection;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
-import java.util.WeakHashMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArraySet;
 
@@ -25,11 +24,15 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * <p>This abstract class serves as a basis for implementations of binding providers that retrieve binding
+ * <p>
- * information from the items configuration file(s), i.e. they register as {@link BindingConfigReader}s.</p>
+ * This abstract class serves as a basis for implementations of binding providers that retrieve binding
+ * information from the items configuration file(s), i.e. they register as {@link BindingConfigReader}s.
+ * </p>
  *
- * <p>This class takes care of tracking all changes in the binding config strings and makes sure that all
+ * <p>
- * listeners are correctly notified of any change.<p>
+ * This class takes care of tracking all changes in the binding config strings and makes sure that all
+ * listeners are correctly notified of any change.
+ * <p>
  *
  * @author Kai Kreuzer
  * @since 0.6.0
@@ -42,7 +45,7 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     private Set<BindingChangeListener> listeners = new CopyOnWriteArraySet<BindingChangeListener>();
 
     /** caches binding configurations. maps itemNames to {@link BindingConfig}s */
-	protected Map<String, BindingConfig> bindingConfigs = new ConcurrentHashMap<String, BindingConfig>(new WeakHashMap<String, BindingConfig>());
+    protected Map<String, BindingConfig> bindingConfigs = new ConcurrentHashMap<String, BindingConfig>();
 
     /**
      * stores information about the context of items. The map has this content
@@ -50,7 +53,6 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
      */
     protected Map<String, Set<Item>> contextMap = new ConcurrentHashMap<String, Set<Item>>();
 
-
     public AbstractGenericBindingProvider() {
         super();
     }
@@ -58,6 +60,7 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     /**
      * {@inheritDoc}
      */
+    @Override
     public void addBindingChangeListener(BindingChangeListener listener) {
         listeners.add(listener);
     }
@@ -65,6 +68,7 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     /**
      * {@inheritDoc}
      */
+    @Override
     public void removeBindingChangeListener(BindingChangeListener listener) {
         listeners.remove(listener);
     }
@@ -72,28 +76,40 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     /**
      * {@inheritDoc}
      */
-	public void processBindingConfiguration(String context, Item item, String bindingConfig) throws BindingConfigParseException {
+    @Override
+    public void processBindingConfiguration(String context, Item item, String bindingConfig)
+            throws BindingConfigParseException {
+        if (context == null) {
+            throw new BindingConfigParseException("null context is not permitted for item " + item.getName());
+        }
+        synchronized (contextMap) {
             Set<Item> items = contextMap.get(context);
-		if (items==null) {
+            if (items == null) {
                 items = new HashSet<Item>();
                 contextMap.put(context, items);
             }
-			
             items.add(item);
         }
+    }
 
     /**
      * {@inheritDoc}
      */
+    @Override
     public void removeConfigurations(String context) {
-		Set<Item> items = contextMap.get(context);
+        Set<Item> items = null;
-		if(items!=null) {
+        synchronized (contextMap) {
-			for(Item item : items) {
+            items = contextMap.get(context);
+            if (items != null) {
+                contextMap.remove(context);
+            }
+        }
+        if (items != null) {
+            for (Item item : items) {
                 // we remove all binding configurations for all items
                 bindingConfigs.remove(item.getName());
                 notifyListeners(item);
             }
-			contextMap.remove(context);
         }
     }
 
@@ -115,6 +131,7 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     /**
      * @{inheritDoc}
      */
+    @Override
     public boolean providesBindingFor(String itemName) {
         return bindingConfigs.get(itemName) != null;
     }
@@ -122,6 +139,7 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     /**
      * @{inheritDoc}
      */
+    @Override
     public boolean providesBinding() {
         return !bindingConfigs.isEmpty();
     }
@@ -129,6 +147,7 @@ public abstract class AbstractGenericBindingProvider implements BindingConfigRea
     /**
      * {@inheritDoc}
      */
+    @Override
     public Collection<String> getItemNames() {
         return new ArrayList<String>(bindingConfigs.keySet());
     }