Postgres implementation (#1142)

* WIP for https://github.com/BentoBoxWorld/BentoBox/issues/1093

* JSON based PostGresql

* Completes PostgreSQL suport

* Changed Postgres connector comments

* Put back rest of Postgres jdbc URL

* Update PostgreSQLDatabaseHandler.java

pom.xml

@@ -221,6 +221,11 @@
             <artifactId>mongodb-driver</artifactId>
             <version>${mongodb.version}</version>
         </dependency>
+        <dependency>
+            <groupId>postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>9.1-901-1.jdbc4</version>
+        </dependency>
         <!-- Vault: as their maven repo is down, we need to get it from jitpack -->
         <!-- See https://github.com/MilkBowl/VaultAPI/issues/69 -->
         <dependency>
@@ -345,7 +350,7 @@
                     <failOnError>false</failOnError>
                     <additionalJOption>-Xdoclint:none</additionalJOption>
                     <!-- To compile with Java 11, this tag may be required -->
-                    <!--  <javadocExecutable>${java.home}/bin/javadoc</javadocExecutable>-->
+                    <!-- <javadocExecutable>${java.home}/bin/javadoc</javadocExecutable> -->
                 </configuration>
                 <executions>
                     <execution>

src/main/java/world/bentobox/bentobox/Settings.java

@@ -51,17 +51,18 @@ public class Settings implements ConfigObject {
     private boolean useEconomy = true;
 
     // Database
-    @ConfigComment("JSON, MYSQL, MARIADB, MONGODB, SQLITE and YAML(deprecated).")
+    @ConfigComment("JSON, MYSQL, MARIADB, MONGODB, SQLITE, POSTGRESQL and YAML(deprecated).")
     @ConfigComment("Transition database options are:")
     @ConfigComment("  YAML2JSON, YAML2MARIADB, YAML2MYSQL, YAML2MONGODB, YAML2SQLITE")
-    @ConfigComment("  JSON2MARIADB, JSON2MYSQL, JSON2MONGODB, JSON2SQLITE,")
+    @ConfigComment("  JSON2MARIADB, JSON2MYSQL, JSON2MONGODB, JSON2SQLITE, JSON2POSTGRESQL")
-    @ConfigComment("  MYSQL2JSON, MARIADB2JSON, MONGODB2JSON, SQLITE2JSON")
+    @ConfigComment("  MYSQL2JSON, MARIADB2JSON, MONGODB2JSON, SQLITE2JSON, POSTGRES2JSON")
     @ConfigComment("If you need others, please make a feature request.")
     @ConfigComment("Minimum required versions:")
     @ConfigComment("   MySQL versions 5.7 or later")
     @ConfigComment("   MariaDB versions 10.2.3 or later")
     @ConfigComment("   MongoDB versions 3.6 or later")
     @ConfigComment("   SQLite versions 3.28 or later")
+    @ConfigComment("   PostgreSQL versions 9.4 or later")
     @ConfigComment("Transition options enable migration from one database type to another. Use /bbox migrate.")
     @ConfigComment("YAML and JSON are file-based databases.")
     @ConfigComment("MYSQL might not work with all implementations: if available, use a dedicated database type (e.g. MARIADB).")

src/main/java/world/bentobox/bentobox/database/sql/postgresql/PostgreSQLDatabaseConnector.java

@@ -1,6 +1,7 @@
 package world.bentobox.bentobox.database.sql.postgresql;
 
 import org.eclipse.jdt.annotation.NonNull;
+import org.postgresql.Driver;
 
 import world.bentobox.bentobox.database.DatabaseConnectionSettingsImpl;
 import world.bentobox.bentobox.database.sql.SQLDatabaseConnector;
@@ -11,6 +12,17 @@ import world.bentobox.bentobox.database.sql.SQLDatabaseConnector;
  */
 public class PostgreSQLDatabaseConnector extends SQLDatabaseConnector {
 
+    /*
+     * Ensure the driver is loaded as JDBC Driver might be invisible to Java's ServiceLoader.
+     * Usually, this is not required as {@link DriverManager} detects JDBC drivers
+     * via {@code META-INF/services/java.sql.Driver} entries. However there might be cases when the driver
+     * is located at the application level classloader, thus it might be required to perform manual
+     * registration of the driver.
+     */
+    static {
+        new Driver();
+    }
+    
     /**
      * Class for PostgreSQL database connections using the settings provided
      * @param dbSettings - database settings

src/main/java/world/bentobox/bentobox/database/sql/postgresql/PostgreSQLDatabaseHandler.java

@@ -1,7 +1,13 @@
 package world.bentobox.bentobox.database.sql.postgresql;
 
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+import com.google.gson.Gson;
+
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.database.DatabaseConnector;
+import world.bentobox.bentobox.database.objects.DataObject;
 import world.bentobox.bentobox.database.sql.SQLConfiguration;
 import world.bentobox.bentobox.database.sql.SQLDatabaseHandler;
 
@@ -9,8 +15,8 @@ import world.bentobox.bentobox.database.sql.SQLDatabaseHandler;
  *
  * @param <T>
  *
- * @since 1.6.0
+ * @since 1.11.0
- * @author tastybento, Poslovitch
+ * @author tastybento
  */
 public class PostgreSQLDatabaseHandler<T> extends SQLDatabaseHandler<T> {
 
@@ -23,7 +29,50 @@ public class PostgreSQLDatabaseHandler<T> extends SQLDatabaseHandler<T> {
      * @param databaseConnector Contains the settings to create a connection to the database
      */
     PostgreSQLDatabaseHandler(BentoBox plugin, Class<T> type, DatabaseConnector databaseConnector) {
-        super(plugin, type, databaseConnector, new SQLConfiguration(type.getCanonicalName()));
+        super(plugin, type, databaseConnector, new SQLConfiguration(type.getCanonicalName())
+                // Set uniqueid as the primary key (index). Postgresql convention is to use lower case field names
+                // Postgresql also uses double quotes (") instead of (`) around tables names with dots.
+                .schema("CREATE TABLE IF NOT EXISTS \"" + type.getCanonicalName() + "\" (uniqueid VARCHAR PRIMARY KEY, json jsonb NOT NULL)")
+                .loadObject("SELECT * FROM \"" + type.getCanonicalName() + "\" WHERE uniqueid = ? LIMIT 1")
+                .deleteObject("DELETE FROM \"" + type.getCanonicalName() + "\" WHERE uniqueid = ?")
+                // uniqueId has to be added into the row explicitly so we need to override the saveObject method
+                // The json value is a string but has to be cast to json when done in Java
+                .saveObject("INSERT INTO \"" + type.getCanonicalName() + "\" (uniqueid, json) VALUES (?, cast(? as json)) "
+                        // This is the Postgresql version of UPSERT.
+                        + "ON CONFLICT (uniqueid) "
+                        + "DO UPDATE SET json = cast(? as json)")
+                .loadObjects("SELECT json FROM \"" + type.getCanonicalName() + "\"")
+                // Postgres exists function returns true or false natively
+                .objectExists("SELECT EXISTS(SELECT * FROM \"" + type.getCanonicalName() + "\" WHERE uniqueid = ?)")
+                );
     }
 
+    /* (non-Javadoc)
+     * @see world.bentobox.bentobox.database.sql.SQLDatabaseHandler#saveObject(java.lang.Object)
+     */
+    @Override
+    public void saveObject(T instance) {
+        // Null check
+        if (instance == null) {
+            plugin.logError("Postgres database request to store a null. ");
+            return;
+        }
+        if (!(instance instanceof DataObject)) {
+            plugin.logError("This class is not a DataObject: " + instance.getClass().getName());
+            return;
+        }
+        Gson gson = getGson();
+        String toStore = gson.toJson(instance);
+        String uniqueId = ((DataObject)instance).getUniqueId();
+        processQueue.add(() -> {
+            try (PreparedStatement preparedStatement = getConnection().prepareStatement(getSqlConfig().getSaveObjectSQL())) {
+                preparedStatement.setString(1, uniqueId); // INSERT
+                preparedStatement.setString(2, toStore); // INSERT
+                preparedStatement.setString(3, toStore); // ON CONFLICT
+                preparedStatement.execute();
+            } catch (SQLException e) {
+                plugin.logError("Could not save object " + instance.getClass().getName() + " " + e.getMessage());
+            }
+        });
+    }
 }

src/main/resources/config.yml

@@ -29,17 +29,18 @@ general:
   # If there is no economy plugin present anyway, money will be automatically disabled.
   use-economy: true
   database:
-    # JSON, MYSQL, MARIADB, MONGODB, SQLITE and YAML(deprecated).
+    # JSON, MYSQL, MARIADB, MONGODB, SQLITE, POSTGRESQL and YAML(deprecated).
     # Transition database options are:
     #   YAML2JSON, YAML2MARIADB, YAML2MYSQL, YAML2MONGODB, YAML2SQLITE
-    #   JSON2MARIADB, JSON2MYSQL, JSON2MONGODB, JSON2SQLITE,
+    #   JSON2MARIADB, JSON2MYSQL, JSON2MONGODB, JSON2SQLITE, JSON2POSTGRESQL
-    #   MYSQL2JSON, MARIADB2JSON, MONGODB2JSON, SQLITE2JSON
+    #   MYSQL2JSON, MARIADB2JSON, MONGODB2JSON, SQLITE2JSON, POSTGRESQL2JSON
     # If you need others, please make a feature request.
     # Minimum required versions:
     #    MySQL versions 5.7 or later
     #    MariaDB versions 10.2.3 or later
     #    MongoDB versions 3.6 or later
     #    SQLite versions 3.28 or later
+    #    PostgreSQL versions 9.4 or later
     # Transition options enable migration from one database type to another. Use /bbox migrate.
     # YAML and JSON are file-based databases.
     # MYSQL might not work with all implementations: if available, use a dedicated database type (e.g. MARIADB).