Creating persistence service.
Change-Id: Ib78b4001a24c71b4096e5a2a446dbd5009aa1090
diff --git a/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceManager.java b/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceManager.java
new file mode 100644
index 0000000..64a8683
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+++ b/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceManager.java
@@ -0,0 +1,138 @@
+/*
+ * 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.persistence.impl;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.mapdb.DB;
+import org.mapdb.DBMaker;
+import org.onosproject.persistence.PersistenceService;
+import org.onosproject.persistence.PersistentMapBuilder;
+import org.onosproject.persistence.PersistentSetBuilder;
+import org.slf4j.Logger;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Map;
+import java.util.Set;
+import java.util.Timer;
+import java.util.TimerTask;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Service that maintains local disk backed maps and sets. This implementation automatically deletes empty structures
+ * on shutdown.
+ */
+@Component(immediate = true)
+@Service
+public class PersistenceManager implements PersistenceService {
+
+ private static final String DATABASE_PATH = "../data/localDB";
+
+ private static final String ENCLOSING_FOLDER = "../data";
+
+ static final String MAP_PREFIX = "map:";
+
+ static final String SET_PREFIX = "set:";
+
+ private final Logger log = getLogger(getClass());
+
+ private DB localDB = null;
+
+ private static final int FLUSH_FREQUENCY_MILLIS = 3000;
+
+ private final Timer timer = new Timer();
+
+ private final CommitTask commitTask = new CommitTask();
+
+ @Activate
+ public void activate() {
+ Path dbPath = Paths.get(DATABASE_PATH);
+ Path dbFolderPath = Paths.get(ENCLOSING_FOLDER);
+ //Make sure the directory exists, if it does not, make it.
+ if (!dbFolderPath.toFile().isDirectory()) {
+ log.info("The specified folder location for the database did not exist and will be created.");
+ try {
+ Files.createDirectories(dbFolderPath);
+ } catch (IOException e) {
+ log.error("Could not create the required folder for the database.");
+ throw new PersistenceException("Database folder could not be created.");
+ }
+ }
+ //Notify if the database file does not exist.
+ boolean dbFound = Files.exists(dbPath);
+ if (!dbFound) {
+ log.info("The database file could not be located, a new database will be constructed.");
+
+ } else {
+ log.info("A previous database file has been found.");
+ }
+ localDB = DBMaker.newFileDB(dbPath.toFile())
+ .asyncWriteEnable()
+ .closeOnJvmShutdown()
+ .make();
+ timer.schedule(commitTask, FLUSH_FREQUENCY_MILLIS, FLUSH_FREQUENCY_MILLIS);
+ log.info("Started");
+ }
+
+ @Deactivate
+ public void deactivate() {
+ for (Map.Entry<String, Object> entry : localDB.getAll().entrySet()) {
+ String key = entry.getKey();
+ Object value = entry.getValue();
+ //This is a map implementation to be handled as such
+ if (value instanceof Map) {
+ Map asMap = (Map) value;
+ if (asMap.isEmpty()) {
+ //the map is empty and may be deleted
+ localDB.delete(key);
+ }
+ //This is a set implementation and can be handled as such
+ } else if (value instanceof Set) {
+ Set asSet = (Set) value;
+ if (asSet.isEmpty()) {
+ //the set is empty and may be deleted
+ localDB.delete(key);
+ }
+ }
+ }
+ localDB.commit();
+ localDB.close();
+ log.info("Stopped");
+ }
+
+ public <K, V> PersistentMapBuilder<K, V> persistentMapBuilder() {
+ return new DefaultPersistentMapBuilder<>(localDB);
+ }
+
+ public <E> PersistentSetBuilder<E> persistentSetBuilder() {
+ return new DefaultPersistentSetBuilder<>(localDB);
+ }
+
+ private class CommitTask extends TimerTask {
+
+ @Override
+ public void run() {
+ localDB.commit();
+ }
+ }
+}
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