How to use

PageChangeListener

in

org.eclipse.smarthome.io.rest.sitemap.internal

private void constructAndSendEvents(Item item, State newState) {
  Set<SitemapEvent> events = constructSitemapEvents(item, newState, widgets);
  for (SitemapEvent event : events) {
    for (SitemapSubscriptionCallback callback : distinctCallbacks) {
      callback.onEvent(event);
    }
  }
}

private void removeCallbackFromListener(String sitemapPage, SitemapSubscriptionCallback callback) {
  PageChangeListener oldListener = pageChangeListeners.get(sitemapPage);
  if (oldListener != null) {
    oldListener.removeCallback(callback);
    if (!pageOfSubscription.values().contains(sitemapPage)) {
      // no other callbacks are left here, so we can safely dispose the listener
      oldListener.dispose();
      pageChangeListeners.remove(sitemapPage);
    }
  }
}

/**
 * Creates a new instance.
 *
 * @param sitemapName the sitemap name of the page
 * @param pageId the id of the page for which events are created
 * @param itemUIRegistry the ItemUIRegistry which is needed for the functionality
 * @param widgets the list of widgets that are part of the page.
 */
public PageChangeListener(String sitemapName, String pageId, ItemUIRegistry itemUIRegistry, EList<Widget> widgets) {
  this.sitemapName = sitemapName;
  this.pageId = pageId;
  this.itemUIRegistry = itemUIRegistry;
  updateItemsAndWidgets(widgets);
}

private void addCallbackToListener(String sitemapName, String pageId, SitemapSubscriptionCallback callback) {
  PageChangeListener listener = pageChangeListeners.get(getValue(sitemapName, pageId));
  if (listener == null) {
    // there is no listener for this page yet, so let's try to create one
    listener = new PageChangeListener(sitemapName, pageId, itemUIRegistry, collectWidgets(sitemapName, pageId));
    pageChangeListeners.put(getValue(sitemapName, pageId), listener);
  }
  if (listener != null) {
    listener.addCallback(callback);
  }
}

/**
 * Collects all items that are represented by a given list of widgets
 *
 * @param widgets
 *            the widget list to get the items for added to all bundles containing REST resources
 * @return all items that are represented by the list of widgets
 */
private Set<Item> getAllItems(EList<Widget> widgets) {
  Set<Item> items = new HashSet<Item>();
  if (itemUIRegistry != null) {
    for (Widget widget : widgets) {
      addItemWithName(items, widget.getItem());
      if (widget instanceof Frame) {
        items.addAll(getAllItems(((Frame) widget).getChildren()));
      }
      // now scan visibility rules
      for (VisibilityRule vr : widget.getVisibility()) {
        addItemWithName(items, vr.getItem());
      }
    }
  }
  return items;
}

protected void deactivate() {
  pageOfSubscription.clear();
  callbacks.clear();
  for (PageChangeListener listener : pageChangeListeners.values()) {
    listener.dispose();
  }
  pageChangeListeners.clear();
}

private Set<SitemapEvent> constructSitemapEvents(Item item, List<Widget> widgets) {
  Set<SitemapEvent> events = new HashSet<>();
  for (Widget w : widgets) {
    if (w instanceof Frame) {
      events.addAll(constructSitemapEvents(item, itemUIRegistry.getChildren((Frame) w)));
    }
    if ((w.getItem() != null && w.getItem().equals(item.getName())) || definesVisibility(w, item.getName())) {
      SitemapWidgetEvent event = new SitemapWidgetEvent();
      event.sitemapName = sitemapName;
      event.pageId = pageId;
      event.label = itemUIRegistry.getLabel(w);
      event.labelcolor = itemUIRegistry.getLabelColor(w);
      event.valuecolor = itemUIRegistry.getValueColor(w);
      event.widgetId = itemUIRegistry.getWidgetId(w);
      event.visibility = itemUIRegistry.getVisiblity(w);
      event.item = EnrichedItemDTOMapper.map(item, false, null, null);
      // adjust the state according to the widget type
      event.item.state = itemUIRegistry.getState(w).toFullString();
      events.add(event);
    }
  }
  return events;
}

for (Widget w : widgets) {
  if (w instanceof Frame) {
    events.addAll(constructSitemapEvents(item, state, itemUIRegistry.getChildren((Frame) w)));
    skipWidget = chartWidget.getRefresh() > 0;
  if (!skipWidget || definesVisibilityOrColor(w, item.getName())) {
    SitemapWidgetEvent event = new SitemapWidgetEvent();
    event.sitemapName = sitemapName;

  @Override
  public void modelChanged(String modelName, EventType type) {
    if (type != EventType.MODIFIED || !modelName.endsWith(SITEMAP_SUFFIX)) {
      return; // we process only sitemap modifications here
    }

    String changedSitemapName = StringUtils.removeEnd(modelName, SITEMAP_SUFFIX);

    for (Entry<String, PageChangeListener> listenerEntry : pageChangeListeners.entrySet()) {
      String sitemapWithPage = listenerEntry.getKey();
      String sitemapName = extractSitemapName(sitemapWithPage);

      if (sitemapName.equals(changedSitemapName)) {
        listenerEntry.getValue().sitemapContentChanged();
      }
    }
  }
}

private void updateItemsAndWidgets(EList<Widget> widgets) {
  if (this.widgets != null) {
    // cleanup statechange listeners in case widgets were removed
    items = getAllItems(this.widgets);
    for (Item item : items) {
      if (item instanceof GenericItem) {
        ((GenericItem) item).removeStateChangeListener(this);
      }
    }
  }
  this.widgets = widgets;
  items = getAllItems(widgets);
  for (Item item : items) {
    if (item instanceof GenericItem) {
      ((GenericItem) item).addStateChangeListener(this);
    }
  }
}

  @Override
  public void receive(Event event) {
    if (event instanceof ItemStatePredictedEvent) {
      ItemStatePredictedEvent prediction = (ItemStatePredictedEvent) event;
      Item item = itemUIRegistry.get(prediction.getItemName());
      if (item instanceof GroupItem) {
        // don't send out auto-update events for group items as those will calculate their state based on their
        // members and predictions aren't really possible in that case (or at least would be highly complex).
        return;
      }
      for (PageChangeListener pageChangeListener : pageChangeListeners.values()) {
        if (prediction.isConfirmation()) {
          pageChangeListener.keepCurrentState(item);
        } else {
          pageChangeListener.changeStateTo(item, prediction.getPredictedState());
        }
      }
    }
  }
}

private void addCallbackToListener(String sitemapName, String pageId, SitemapSubscriptionCallback callback) {
  PageChangeListener listener = pageChangeListeners.get(getValue(sitemapName, pageId));
  if (listener == null) {
    // there is no listener for this page yet, so let's try to create one
    listener = new PageChangeListener(sitemapName, pageId, itemUIRegistry, collectWidgets(sitemapName, pageId));
    pageChangeListeners.put(getValue(sitemapName, pageId), listener);
  }
  if (listener != null) {
    listener.addCallback(callback);
  }
}

if (itemUIRegistry != null) {
  for (Widget widget : widgets) {
    addItemWithName(items, widget.getItem());
    if (widget instanceof Frame) {
      items.addAll(getAllItems(((Frame) widget).getChildren()));
      addItemWithName(items, rule.getItem());
      addItemWithName(items, rule.getItem());
      addItemWithName(items, rule.getItem());

@Deactivate
protected void deactivate() {
  pageOfSubscription.clear();
  callbacks.clear();
  for (PageChangeListener listener : pageChangeListeners.values()) {
    listener.dispose();
  }
  pageChangeListeners.clear();
}

@Override
public void modelChanged(String modelName, EventType type) {
  if (type != EventType.MODIFIED || !modelName.endsWith(SITEMAP_SUFFIX)) {
    return; // we process only sitemap modifications here
  }
  String changedSitemapName = StringUtils.removeEnd(modelName, SITEMAP_SUFFIX);
  for (Entry<String, PageChangeListener> listenerEntry : pageChangeListeners.entrySet()) {
    String sitemapWithPage = listenerEntry.getKey();
    String sitemapName = extractSitemapName(sitemapWithPage);
    String pageId = extractPageId(sitemapWithPage);
    if (sitemapName.equals(changedSitemapName)) {
      EList<Widget> widgets = collectWidgets(sitemapName, pageId);
      listenerEntry.getValue().sitemapContentChanged(widgets);
    }
  }
}

private void updateItemsAndWidgets(EList<Widget> widgets) {
  if (this.widgets != null) {
    // cleanup statechange listeners in case widgets were removed
    items = getAllItems(this.widgets);
    for (Item item : items) {
      if (item instanceof GenericItem) {
        ((GenericItem) item).removeStateChangeListener(this);
      }
    }
  }
  this.widgets = widgets;
  items = getAllItems(widgets);
  for (Item item : items) {
    if (item instanceof GenericItem) {
      ((GenericItem) item).addStateChangeListener(this);
    }
  }
}

private void removeCallbackFromListener(String sitemapPage, SitemapSubscriptionCallback callback) {
  PageChangeListener oldListener = pageChangeListeners.get(sitemapPage);
  if (oldListener != null) {
    oldListener.removeCallback(callback);
    if (!pageOfSubscription.values().contains(sitemapPage)) {
      // no other callbacks are left here, so we can safely dispose the listener
      oldListener.dispose();
      pageChangeListeners.remove(sitemapPage);
    }
  }
}

/**
 * Removes an existing subscription
 *
 * @param subscriptionId the id of the subscription to remove
 */
public void removeSubscription(String subscriptionId) {
  callbacks.remove(subscriptionId);
  String sitemapPage = pageOfSubscription.remove(subscriptionId);
  if (sitemapPage != null && !pageOfSubscription.values().contains(sitemapPage)) {
    // this was the only subscription listening on this page, so we can dispose the listener
    PageChangeListener listener = pageChangeListeners.remove(sitemapPage);
    if (listener != null) {
      listener.dispose();
    }
  }
  logger.debug("Removed subscription with id {}", subscriptionId);
}

/**
 * Creates a new instance.
 *
 * @param sitemapName the sitemap name of the page
 * @param pageId the id of the page for which events are created
 * @param itemUIRegistry the ItemUIRegistry which is needed for the functionality
 * @param widgets the list of widgets that are part of the page.
 */
public PageChangeListener(String sitemapName, String pageId, ItemUIRegistry itemUIRegistry, EList<Widget> widgets) {
  this.sitemapName = sitemapName;
  this.pageId = pageId;
  this.itemUIRegistry = itemUIRegistry;
  updateItemsAndWidgets(widgets);
}

@Override
public void stateChanged(Item item, State oldState, State newState) {
  // For all items except group, send an event only when the event state is changed.
  if (item instanceof GroupItem) {
    return;
  }
  Set<SitemapEvent> events = constructSitemapEvents(item, widgets);
  for (SitemapEvent event : events) {
    for (SitemapSubscriptionCallback callback : distinctCallbacks) {
      callback.onEvent(event);
    }
  }
}