org.silverpeas.core.web.index.IndexationProcessExecutor.java Source code

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Here is the source code for org.silverpeas.core.web.index.IndexationProcessExecutor.java

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/*
 * Copyright (C) 2000 - 2018 Silverpeas
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * As a special exception to the terms and conditions of version 3.0 of
 * the GPL, you may redistribute this Program in connection with Free/Libre
 * Open Source Software ("FLOSS") applications as described in Silverpeas's
 * FLOSS exception.  You should have received a copy of the text describing
 * the FLOSS exception, and it is also available here:
 * "https://www.silverpeas.org/legal/floss_exception.html"
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.silverpeas.core.web.index;

import org.apache.commons.lang3.tuple.Pair;
import org.silverpeas.core.cache.model.Cache;
import org.silverpeas.core.cache.service.CacheServiceProvider;
import org.silverpeas.core.thread.ManagedThreadPool;
import org.silverpeas.core.util.ServiceProvider;
import org.silverpeas.core.util.logging.SilverLogger;

import javax.inject.Singleton;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;

import static org.silverpeas.core.thread.ManagedThreadPool.ExecutionConfig.defaultConfig;

/**
 * Handles the execution of huge indexation process.
 * @author Yohann Chastagnier
 */
@Singleton
public class IndexationProcessExecutor {
    private static final String INDEXATION_PROCESS_EXECUTOR_KEY = "INDEXATION_PROCESS_EXECUTOR_KEY";

    /**
     * Hidden constructor.
     */
    private IndexationProcessExecutor() {
    }

    public static IndexationProcessExecutor get() {
        return ServiceProvider.getService(IndexationProcessExecutor.class);
    }

    /**
     * Indicates if an indexation operation is currently running.
     * @return true if there is a current execution, false otherwise.
     */
    @SuppressWarnings("unchecked")
    public boolean isCurrentExecution() {
        final Cache cache = CacheServiceProvider.getApplicationCacheService().getCache();
        Pair<IndexationProcess, Future<Void>> process = cache.get(INDEXATION_PROCESS_EXECUTOR_KEY, Pair.class);
        return process != null && !process.getRight().isDone();
    }

    /**
     * Stops a current indexation operation if it exists a running one.<br>
     * Otherwise, nothing is done.
     */
    @SuppressWarnings({ "unchecked", "WeakerAccess", "unused" })
    public void stopCurrentExecutionIfAny() {
        final Cache cache = CacheServiceProvider.getApplicationCacheService().getCache();
        Pair<IndexationProcess, Future<Void>> process = cache.get(INDEXATION_PROCESS_EXECUTOR_KEY, Pair.class);
        final Future<Void> task = (process != null) ? process.getRight() : null;
        if (process != null && !task.isDone()) {
            try {
                task.cancel(true);
            } catch (Exception e) {
                SilverLogger.getLogger(this).error("stopping indexation process failed", e);
            }
        }
    }

    /**
     * Executes an indexation process.<br>
     * There is no error of an other one is already running.<br>
     * The monitoring of executions has to be performed by caller by using {@link
     * #isCurrentExecution()} and {@link #stopCurrentExecutionIfAny()} methods.
     * @param indexationProcess the indexation process to execute.
     */
    public void execute(IndexationProcess indexationProcess) {
        final Cache cache = CacheServiceProvider.getApplicationCacheService().getCache();
        try {
            if (isCurrentExecution()) {
                SilverLogger.getLogger(this)
                        .warn("an indexation processing is already running, how is it possible ? That is a huge "
                                + "treatment which one and only one should be running at a same time!!!");
                SilverLogger.getLogger(this).warn("so the new indexation request has been ignored");
                return;
            }
            Future<Void> future = ManagedThreadPool.getPool().invoke(indexationProcess,
                    defaultConfig().withMaxThreadPoolSizeOf(1));
            cache.put(INDEXATION_PROCESS_EXECUTOR_KEY, Pair.of(indexationProcess, future), 0, 0);
        } catch (Exception e) {
            SilverLogger.getLogger(this).error("starting indexation process failed", e);
        }
    }

    public abstract static class IndexationProcess implements Callable<Void> {

        public abstract void perform();

        @Override
        public Void call() {
            final String threadId = String.valueOf(Thread.currentThread().getId());
            try {
                SilverLogger.getLogger(IndexationProcessExecutor.class)
                        .info("starting indexation process on thread with id ''{0}'')", threadId);
                perform();
                SilverLogger.getLogger(IndexationProcessExecutor.class)
                        .info("ending indexation process on thread with id ''{0}'')", threadId);
            } catch (Exception e) {
                SilverLogger.getLogger(IndexationProcessExecutor.class).error(
                        "indexation process failure on thread with id ''{0}'')", new Object[] { threadId }, e);
            }
            return null;
        }
    }
}