Hook the ChannelItemProvider into the ItemRegistry (#4580)

* Hook the ChannelItemProvider into the ItemRegistry ...so it gets informed before (resp. after) items are added (resp. removed) by other providers. fixes #4565 Signed-off-by: Simon Kaufmann <simon.kfm@googlemail.com>
eclipse-archived · Nov 17, 2017 · 9d6b17c · 9d6b17c
1 parent a382bf9
commit 9d6b17c
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Showing 6 changed files with 123 additions and 13 deletions.
diff --git a/...test/src/test/java/org/eclipse/smarthome/core/thing/internal/ChannelItemProviderTest.java b/...test/src/test/java/org/eclipse/smarthome/core/thing/internal/ChannelItemProviderTest.java
@@ -110,7 +110,7 @@ public void testItemRemoval_itemFromOtherProvider() throws Exception {
 
         resetAndPrepareListener();
 
-        provider.itemRegistryListener.added(new NumberItem(ITEM_NAME));
+        provider.itemRegistryListener.beforeAdding(new NumberItem(ITEM_NAME));
         verify(listener, only()).removed(same(provider), same(ITEM));
         verify(listener, never()).added(same(provider), same(ITEM));
     }
@@ -120,12 +120,12 @@ private void resetAndPrepareListener() {
         reset(listener);
         doAnswer(invocation -> {
             // this is crucial as it mimicks the real ItemRegistry's behavior
-            provider.itemRegistryListener.removed((Item) invocation.getArguments()[1]);
+            provider.itemRegistryListener.afterRemoving((Item) invocation.getArguments()[1]);
             return null;
         }).when(listener).removed(same(provider), any(Item.class));
         doAnswer(invocation -> {
             // this is crucial as it mimicks the real ItemRegistry's behavior
-            provider.itemRegistryListener.added((Item) invocation.getArguments()[1]);
+            provider.itemRegistryListener.beforeAdding((Item) invocation.getArguments()[1]);
             return null;
         }).when(listener).added(same(provider), any(Item.class));
         when(linkRegistry.getBoundChannels(eq(ITEM_NAME))).thenReturn(Collections.singleton(CHANNEL_UID));

diff --git a/...re.thing/src/main/java/org/eclipse/smarthome/core/thing/internal/ChannelItemProvider.java b/...re.thing/src/main/java/org/eclipse/smarthome/core/thing/internal/ChannelItemProvider.java
@@ -26,6 +26,7 @@
 import org.eclipse.smarthome.core.items.ItemFactory;
 import org.eclipse.smarthome.core.items.ItemProvider;
 import org.eclipse.smarthome.core.items.ItemRegistry;
+import org.eclipse.smarthome.core.items.RegistryHook;
 import org.eclipse.smarthome.core.thing.Channel;
 import org.eclipse.smarthome.core.thing.ChannelUID;
 import org.eclipse.smarthome.core.thing.Thing;
@@ -58,13 +59,13 @@ public class ChannelItemProvider implements ItemProvider {
 
     private final Logger logger = LoggerFactory.getLogger(ChannelItemProvider.class);
 
-    private Set<ProviderChangeListener<Item>> listeners = new HashSet<>();
+    private final Set<ProviderChangeListener<Item>> listeners = new HashSet<>();
 
     private LocaleProvider localeProvider;
     private ThingRegistry thingRegistry;
     private ItemChannelLinkRegistry linkRegistry;
     private ItemRegistry itemRegistry;
-    private Set<ItemFactory> itemFactories = new HashSet<>();
+    private final Set<ItemFactory> itemFactories = new HashSet<>();
     private Map<String, Item> items = null;
 
     private boolean enabled = true;
@@ -212,12 +213,12 @@ protected void deactivate() {
 
     private void addRegistryChangeListeners() {
         this.linkRegistry.addRegistryChangeListener(linkRegistryListener);
-        this.itemRegistry.addRegistryChangeListener(itemRegistryListener);
+        this.itemRegistry.addRegistryHook(itemRegistryListener);
         this.thingRegistry.addRegistryChangeListener(thingRegistryListener);
     }
 
     private void removeRegistryChangeListeners() {
-        this.itemRegistry.removeRegistryChangeListener(itemRegistryListener);
+        this.itemRegistry.removeRegistryHook(itemRegistryListener);
         this.linkRegistry.removeRegistryChangeListener(linkRegistryListener);
         this.thingRegistry.removeRegistryChangeListener(thingRegistryListener);
     }
@@ -344,10 +345,10 @@ public void updated(ItemChannelLink oldElement, ItemChannelLink element) {
         }
     };
 
-    RegistryChangeListener<Item> itemRegistryListener = new RegistryChangeListener<Item>() {
+    RegistryHook<Item> itemRegistryListener = new RegistryHook<Item>() {
 
         @Override
-        public void added(Item element) {
+        public void beforeAdding(Item element) {
             // check, if it is our own item
             for (Item item : items.values()) {
                 if (item == element) {
@@ -366,7 +367,7 @@ public void added(Item element) {
         }
 
         @Override
-        public void removed(Item element) {
+        public void afterRemoving(Item element) {
             // check, if it is our own item
             for (Item item : items.values()) {
                 if (item == element) {
@@ -383,8 +384,5 @@ public void removed(Item element) {
             }
         }
 
-        @Override
-        public void updated(Item oldElement, Item element) {
-        }
     };
 }
diff --git a/...rthome.core/src/main/java/org/eclipse/smarthome/core/internal/items/ItemRegistryImpl.java b/...rthome.core/src/main/java/org/eclipse/smarthome/core/internal/items/ItemRegistryImpl.java
@@ -14,8 +14,10 @@
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.eclipse.smarthome.core.common.registry.AbstractRegistry;
+import org.eclipse.smarthome.core.common.registry.Provider;
 import org.eclipse.smarthome.core.events.EventPublisher;
 import org.eclipse.smarthome.core.items.GenericItem;
 import org.eclipse.smarthome.core.items.GroupItem;
@@ -26,6 +28,7 @@
 import org.eclipse.smarthome.core.items.ItemRegistry;
 import org.eclipse.smarthome.core.items.ItemUtil;
 import org.eclipse.smarthome.core.items.ManagedItemProvider;
+import org.eclipse.smarthome.core.items.RegistryHook;
 import org.eclipse.smarthome.core.items.events.ItemEventFactory;
 import org.eclipse.smarthome.core.types.StateDescriptionProvider;
 import org.osgi.service.component.ComponentContext;
@@ -49,6 +52,7 @@ public class ItemRegistryImpl extends AbstractRegistry<Item, String, ItemProvide
 
     private final List<StateDescriptionProvider> stateDescriptionProviders = Collections
             .synchronizedList(new ArrayList<StateDescriptionProvider>());
+    private final List<RegistryHook<Item>> registryHooks = new CopyOnWriteArrayList<>();
 
     public ItemRegistryImpl() {
         super(ItemProvider.class);
@@ -325,6 +329,52 @@ protected void notifyListenersAboutUpdatedElement(Item oldElement, Item element)
         postEvent(ItemEventFactory.createUpdateEvent(element, oldElement));
     }
 
+    @Override
+    public void added(Provider<Item> provider, Item element) {
+        for (RegistryHook<Item> registryHook : registryHooks) {
+            registryHook.beforeAdding(element);
+        }
+        super.added(provider, element);
+    }
+
+    @Override
+    protected void addProvider(Provider<Item> provider) {
+        for (Item element : provider.getAll()) {
+            for (RegistryHook<Item> registryHook : registryHooks) {
+                registryHook.beforeAdding(element);
+            }
+        }
+        super.addProvider(provider);
+    }
+
+    @Override
+    public void removed(Provider<Item> provider, Item element) {
+        super.removed(provider, element);
+        for (RegistryHook<Item> registryHook : registryHooks) {
+            registryHook.afterRemoving(element);
+        }
+    }
+
+    @Override
+    protected void removeProvider(Provider<Item> provider) {
+        super.removeProvider(provider);
+        for (Item element : provider.getAll()) {
+            for (RegistryHook<Item> registryHook : registryHooks) {
+                registryHook.afterRemoving(element);
+            }
+        }
+    }
+
+    @Override
+    public void addRegistryHook(RegistryHook<Item> hook) {
+        registryHooks.add(hook);
+    }
+
+    @Override
+    public void removeRegistryHook(RegistryHook<Item> hook) {
+        registryHooks.remove(hook);
+    }
+
     protected void activate(final ComponentContext componentContext) {
         super.activate(componentContext.getBundleContext());
     }

diff --git a/...g.eclipse.smarthome.core/src/main/java/org/eclipse/smarthome/core/items/ItemRegistry.java b/...g.eclipse.smarthome.core/src/main/java/org/eclipse/smarthome/core/items/ItemRegistry.java
@@ -108,4 +108,18 @@ public interface ItemRegistry extends Registry<Item, String> {
      */
     public @Nullable Item remove(@NonNull String itemName, boolean recursive);
 
+    /**
+     * Add a hook to be informed before adding/after removing items.
+     *
+     * @param hook
+     */
+    void addRegistryHook(RegistryHook<Item> hook);
+
+    /**
+     * Remove the hook again.
+     *
+     * @param hook
+     */
+    void removeRegistryHook(RegistryHook<Item> hook);
+
 }
diff --git a/...g.eclipse.smarthome.core/src/main/java/org/eclipse/smarthome/core/items/RegistryHook.java b/...g.eclipse.smarthome.core/src/main/java/org/eclipse/smarthome/core/items/RegistryHook.java
@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2014-2017 by the respective copyright holders.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.eclipse.smarthome.core.items;
+
+import org.eclipse.smarthome.core.common.registry.Identifiable;
+
+/**
+ * A listener to be informed before entities are added respectively after they are removed.
+ *
+ * @author Simon Kaufmann - initial contribution and API.
+ */
+public interface RegistryHook<E extends Identifiable<?>> {
+
+    /**
+     * Notifies the listener that a single element is going to be added by another provider.
+     *
+     * @param element the element to be added
+     */
+    void beforeAdding(E element);
+
+    /**
+     * Notifies the listener that a single element was removed by another provider.
+     *
+     * @param element the element that was removed
+     */
+    void afterRemoving(E element);
+
+}
diff --git a/...marthome.ui/src/main/java/org/eclipse/smarthome/ui/internal/items/ItemUIRegistryImpl.java b/...marthome.ui/src/main/java/org/eclipse/smarthome/ui/internal/items/ItemUIRegistryImpl.java
@@ -31,6 +31,7 @@
 import org.eclipse.smarthome.core.items.ItemNotFoundException;
 import org.eclipse.smarthome.core.items.ItemNotUniqueException;
 import org.eclipse.smarthome.core.items.ItemRegistry;
+import org.eclipse.smarthome.core.items.RegistryHook;
 import org.eclipse.smarthome.core.library.items.CallItem;
 import org.eclipse.smarthome.core.library.items.ColorItem;
 import org.eclipse.smarthome.core.library.items.ContactItem;
@@ -1182,4 +1183,18 @@ public Item remove(String itemName, boolean recursive) {
 
     }
 
+    @Override
+    public void addRegistryHook(RegistryHook<Item> hook) {
+        if (itemRegistry != null) {
+            itemRegistry.addRegistryHook(hook);
+        }
+    }
+
+    @Override
+    public void removeRegistryHook(RegistryHook<Item> hook) {
+        if (itemRegistry != null) {
+            itemRegistry.removeRegistryHook(hook);
+        }
+    }
+
 }