001/*
002 * (C) Copyright 2009-2016 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Radu Darlea
018 *     Catalin Baican
019 *     Florent Guillaume
020 */
021
022package org.nuxeo.ecm.platform.tag;
023
024import static org.nuxeo.ecm.platform.tag.TagConstants.MIGRATION_ID;
025import static org.nuxeo.ecm.platform.tag.TagConstants.MIGRATION_STATE_FACETS;
026import static org.nuxeo.ecm.platform.tag.TagConstants.MIGRATION_STATE_RELATIONS;
027import static org.nuxeo.ecm.platform.tag.TagConstants.MIGRATION_STEP_RELATIONS_TO_FACETS;
028
029import org.nuxeo.runtime.api.Framework;
030import org.nuxeo.runtime.migration.MigrationService;
031import org.nuxeo.runtime.migration.MigrationService.MigrationStatus;
032import org.nuxeo.runtime.migration.MigrationService.StatusChangeNotifier;
033import org.nuxeo.runtime.model.Component;
034import org.nuxeo.runtime.model.ComponentName;
035import org.nuxeo.runtime.model.DefaultComponent;
036
037/**
038 * the tag component.
039 */
040public class TagServiceImpl extends DefaultComponent {
041
042    public static final ComponentName NAME = new ComponentName("org.nuxeo.ecm.platform.tag.TagService");
043
044    // @GuardedBy("this")
045    protected volatile TagService tagService;
046
047    @Override
048    public int getApplicationStartedOrder() {
049        // should deploy before repository service because the tag service is indirectly used (through a listener) by
050        // the repository init handlers
051        Component component = (Component) Framework.getRuntime()
052                                                   .getComponentInstance(
053                                                           "org.nuxeo.ecm.core.repository.RepositoryServiceComponent")
054                                                   .getInstance();
055        return component.getApplicationStartedOrder() - 1;
056    }
057
058    // called under synchronized (this)
059    protected TagService recomputeTagService() {
060        MigrationService migrationService = Framework.getService(MigrationService.class);
061        MigrationStatus status = migrationService.getStatus(MIGRATION_ID);
062        if (status == null) {
063            throw new IllegalStateException("Unknown migration status for: " + MIGRATION_ID);
064        }
065        if (status.isRunning()) {
066            String step = status.getStep();
067            if (MIGRATION_STEP_RELATIONS_TO_FACETS.equals(step)) {
068                return new BridgeTagService(new RelationTagService(), new FacetedTagService());
069            } else {
070                throw new IllegalStateException("Unknown migration step: " + step);
071            }
072        } else {
073            String state = status.getState();
074            if (MIGRATION_STATE_RELATIONS.equals(state)) {
075                return new RelationTagService();
076            } else if (MIGRATION_STATE_FACETS.equals(state)) {
077                return new FacetedTagService();
078            } else {
079                throw new IllegalStateException("Unknown migration state: " + state);
080            }
081        }
082    }
083
084    @Override
085    @SuppressWarnings("unchecked")
086    public <T> T getAdapter(Class<T> adapter) {
087        if (tagService == null) {
088            synchronized (this) {
089                if (tagService == null) {
090                    tagService = recomputeTagService();
091                }
092            }
093        }
094        return (T) tagService;
095    }
096
097    /**
098     * Callback class to notify of migration status changes.
099     *
100     * @since 9.3
101     */
102    public static class TagServiceStatusChangeNotifier implements StatusChangeNotifier {
103        @Override
104        public void notifyStatusChange() {
105            TagServiceImpl tagService = (TagServiceImpl) Framework.getRuntime().getComponent(TagServiceImpl.NAME);
106            tagService.invalidateTagServiceImplementation();
107        }
108    }
109
110    /**
111     * Called when the migration status changes, to recompute the new service.
112     *
113     * @since 9.3
114     */
115    public void invalidateTagServiceImplementation() {
116        synchronized (this) {
117            tagService = recomputeTagService();
118        }
119    }
120
121}