Add h2 key-value store

owlplug-client/pom.xml

@@ -70,7 +70,6 @@
 		<dependency>
 			<groupId>com.h2database</groupId>
 			<artifactId>h2</artifactId>
-			<scope>runtime</scope>
 		</dependency>
 		<dependency>
 			<groupId>ch.qos.logback</groupId>

owlplug-client/src/main/java/com/owlplug/core/components/PersistentKeyValueStore.java

@@ -0,0 +1,73 @@
+/* OwlPlug
+ * Copyright (C) 2021 Arthur <[email protected]>
+ *
+ * This file is part of OwlPlug.
+ *
+ * OwlPlug is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3
+ * as published by the Free Software Foundation.
+ *
+ * OwlPlug 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 General Public License
+ * along with OwlPlug.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.owlplug.core.components;
+
+import jakarta.annotation.PreDestroy;
+import java.util.Map;
+import org.h2.mvstore.MVMap;
+import org.h2.mvstore.MVStore;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+/**
+ * The PersistentKeyValueStore is a key-value based storage manager
+ * to persist user data in the owlplug workspace (usually ~/.owlplug).
+ * The owlplug default data-source is an H2 SQL database semi-persistent.
+ * A relational database allow for some query optimization and full JPA / Spring data support.
+ * Because schema migration is not managed by OwlPlug, the database is cleared
+ * when breaking changes or changes not managed by the hibernate ddl-update parameter are introduced.
+ * All data that need to persist between OwlPlug updates must be stored in this KeyValue Store.
+ */
+@Component
+public class PersistentKeyValueStore {
+
+  private final Logger log = LoggerFactory.getLogger(this.getClass());
+  private final MVStore store;
+
+  public PersistentKeyValueStore() {
+    store = new MVStore.Builder()
+            // TODO configure from application properties
+            .fileName("~/.owlplug/kvstore.mv.db")
+            .open();
+  }
+
+  public void put(String mapName, String key, String value) {
+    MVMap<String, String> map = store.openMap(mapName);
+    map.put(key,value);
+    store.commit();
+  }
+
+  public void putAll(String mapName, Map<String, String> valueMap) {
+    MVMap<String, String> map = store.openMap(mapName);
+    map.putAll(valueMap);
+    store.commit();
+  }
+
+  public String get(String mapName, String key) {
+    MVMap<String, String> map = store.openMap(mapName);
+    return map.get(key);
+  }
+
+  @PreDestroy
+  public void destroy() {
+    log.info("Closing persistent key value store, PreDestroy signal received.");
+    store.close();
+  }
+}