| /* |
| * Copyright 2015 Open Networking Laboratory |
| * |
| * 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.onosproject.ui.impl; |
| |
| import org.onosproject.ui.UiTopoOverlay; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import static com.google.common.base.Strings.isNullOrEmpty; |
| |
| /** |
| * A cache of {@link org.onosproject.ui.UiTopoOverlay}'s that were registered |
| * at the time the UI connection was established. |
| */ |
| public class TopoOverlayCache { |
| |
| private static final String EMPTY = ""; |
| private static final UiTopoOverlay NONE = new NullOverlay(); |
| |
| private final Map<String, UiTopoOverlay> overlays = new HashMap<>(); |
| private UiTopoOverlay current = NONE; |
| |
| public TopoOverlayCache() { |
| overlays.put(null, NONE); |
| } |
| |
| /** |
| * Adds a topology overlay to the cache. |
| * |
| * @param overlay a topology overlay |
| */ |
| public void add(UiTopoOverlay overlay) { |
| overlays.put(overlay.id(), overlay); |
| } |
| |
| /** |
| * Invoked when the cache is no longer needed. |
| */ |
| public void destroy() { |
| overlays.clear(); |
| } |
| |
| /** |
| * Switching currently selected overlay. |
| * |
| * @param deact identity of overlay to deactivate |
| * @param act identity of overlay to activate |
| */ |
| public void switchOverlay(String deact, String act) { |
| UiTopoOverlay toDeactivate = getOverlay(deact); |
| UiTopoOverlay toActivate = getOverlay(act); |
| |
| toDeactivate.deactivate(); |
| current = toActivate; |
| current.activate(); |
| } |
| |
| private UiTopoOverlay getOverlay(String id) { |
| return isNullOrEmpty(id) ? NONE : overlays.get(id); |
| } |
| |
| /** |
| * Returns the current overlay instance. |
| * Note that this method always returns a reference; when there is no |
| * overlay selected the "NULL" overlay instance is returned. |
| * |
| * @return the current overlay |
| */ |
| public UiTopoOverlay currentOverlay() { |
| return current; |
| } |
| |
| /** |
| * Returns the number of overlays in the cache. Remember that this |
| * includes the "NULL" overlay, representing "no overlay selected". |
| * |
| * @return number of overlays |
| */ |
| public int size() { |
| return overlays.size(); |
| } |
| |
| /** |
| * Returns true if the identifier of the currently active overlay |
| * matches the given parameter. |
| * |
| * @param overlayId overlay identifier |
| * @return true if this matches the ID of currently active overlay |
| */ |
| public boolean isActive(String overlayId) { |
| return currentOverlay().id().equals(overlayId); |
| } |
| |
| // overlay instance representing "no overlay selected" |
| private static class NullOverlay extends UiTopoOverlay { |
| public NullOverlay() { |
| super(EMPTY); |
| } |
| } |
| } |