Java tutorial
/* * This file is part of the PDF Split And Merge source code * Created on 13/ago/2014 * Copyright 2013-2014 by Andrea Vacondio (andrea.vacondio@gmail.com). * * 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. * * 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 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.pdfsam.module; import static java.util.stream.Collectors.toList; import static org.apache.commons.lang3.StringUtils.isNotBlank; import java.io.IOException; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.prefs.BackingStoreException; import java.util.prefs.Preferences; import javax.annotation.PreDestroy; import javax.inject.Named; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.fasterxml.jackson.jr.ob.JSON; /** * @author Andrea Vacondio * */ @Named class PreferencesUsageDataStore { private static final Logger LOG = LoggerFactory.getLogger(PreferencesUsageDataStore.class); static final String USAGE_PATH = "/org/pdfsam/modules/usage"; static final String MODULE_USAGE_KEY = "module.usage"; static final String TASKS_EXECUTED_KEY = "tasks.executed"; @PreDestroy public void flush() { Preferences prefs = Preferences.userRoot().node(USAGE_PATH); try { LOG.trace("Flushing modules usage"); prefs.flush(); } catch (BackingStoreException e) { LOG.error("Unable to flush modules usage statistics", e); } } public void incrementUsageFor(String moduleId) { Preferences node = Preferences.userRoot().node(USAGE_PATH).node(moduleId); String json = node.get(MODULE_USAGE_KEY, ""); try { if (isNotBlank(json)) { node.put(MODULE_USAGE_KEY, JSON.std.asString(JSON.std.beanFrom(ModuleUsage.class, json).inc())); } else { node.put(MODULE_USAGE_KEY, JSON.std.asString(ModuleUsage.fistUsage(moduleId))); } LOG.trace("Usage incremented for module {}", moduleId); } catch (IOException e) { LOG.error("Unable to increment modules usage statistics", e); } finally { incrementTotalUsage(); } } public List<ModuleUsage> getUsages() { Preferences prefs = Preferences.userRoot().node(USAGE_PATH); List<ModuleUsage> retList = new ArrayList<>(); try { List<String> jsons = Arrays.stream(prefs.childrenNames()).parallel().map(name -> prefs.node(name)) .map(node -> node.get(MODULE_USAGE_KEY, "")).filter(json -> isNotBlank(json)).collect(toList()); for (String json : jsons) { retList.add(JSON.std.beanFrom(ModuleUsage.class, json)); } } catch (BackingStoreException | IOException e) { LOG.error("Unable to get modules usage statistics", e); } return retList; } public void clear() { Preferences prefs = Preferences.userRoot().node(USAGE_PATH); try { prefs.removeNode(); prefs.flush(); } catch (BackingStoreException e) { LOG.error("Unable to clear modules usage statistics", e); } } private void incrementTotalUsage() { Preferences node = Preferences.userRoot().node(USAGE_PATH); node.putLong(TASKS_EXECUTED_KEY, node.getLong(TASKS_EXECUTED_KEY, 0) + 1); } public long getTotalUsage() { Preferences node = Preferences.userRoot().node(USAGE_PATH); return node.getLong(TASKS_EXECUTED_KEY, 0); } }