From bc7dc206b453baec970e813d1b981cbbe8374cbf Mon Sep 17 00:00:00 2001
From: Luca Frosini <luca.frosini@isti.cnr.it>
Date: Wed, 10 Mar 2021 17:59:25 +0100
Subject: [PATCH] Implementing library

---
 pom.xml                                       |  8 +-
 .../persistence/PersistencePostgreSQL.java    | 74 ++++++++++++++++---
 2 files changed, 69 insertions(+), 13 deletions(-)

diff --git a/pom.xml b/pom.xml
index 8d380e3..6427052 100644
--- a/pom.xml
+++ b/pom.xml
@@ -24,7 +24,7 @@
 		<developerConnection>scm:git:https://code-repo.d4science.org/gCubeSystem/${project.artifactId}.git</developerConnection>
 		<url>https://code-repo.d4science.org/gCubeSystem/${project.artifactId}</url>
 	</scm>
-	
+
 	<dependencyManagement>
 		<dependencies>
 			<dependency>
@@ -46,6 +46,12 @@
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-api</artifactId>
 		</dependency>
+		<!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
+		<dependency>
+			<groupId>org.postgresql</groupId>
+			<artifactId>postgresql</artifactId>
+			<version>42.2.19</version>
+		</dependency>
 		<!-- Test Dependencies -->
 		<dependency>
 			<groupId>junit</groupId>
diff --git a/src/main/java/org/gcube/documentstore/persistence/PersistencePostgreSQL.java b/src/main/java/org/gcube/documentstore/persistence/PersistencePostgreSQL.java
index d91d0a0..d39ea34 100644
--- a/src/main/java/org/gcube/documentstore/persistence/PersistencePostgreSQL.java
+++ b/src/main/java/org/gcube/documentstore/persistence/PersistencePostgreSQL.java
@@ -3,6 +3,12 @@
  */
 package org.gcube.documentstore.persistence;
 
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.Statement;
+import java.util.SortedSet;
+import java.util.TreeSet;
+
 import org.gcube.documentstore.records.Record;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -14,44 +20,88 @@ public class PersistencePostgreSQL extends PersistenceBackend {
 
 	private static final Logger logger = LoggerFactory.getLogger(PersistencePostgreSQL.class);
 
+	public static final String URL_PROPERTY_KEY = "URL";
+	public static final String USERNAME_PROPERTY_KEY = "username";
+	public static final String PASSWORD_PROPERTY_KEY = "password";
+
+	private String url;
+	private String username;
+	private String password;
+
+	private Connection connection;
+	private Statement statement;
+
 	@Override
 	protected void prepareConnection(PersistenceBackendConfiguration configuration) throws Exception {
 		logger.trace("prepareConnection()");
+		url = configuration.getProperty(URL_PROPERTY_KEY);
+		username = configuration.getProperty(USERNAME_PROPERTY_KEY);
+		password = configuration.getProperty(PASSWORD_PROPERTY_KEY);
 	}
 
 	@Override
 	protected void openConnection() throws Exception {
 		logger.trace("openConnection()");
+		try {
+			Class.forName("org.postgresql.Driver");
+			connection = DriverManager.getConnection(url, username, password);
+			logger.trace("Opened database successfully");
+			connection.setAutoCommit(false);
+			statement = connection.createStatement();
+		} catch (Exception e) {
+			throw e;
+		}
 	}
 
-	@Override
-	protected void reallyAccount(Record record) throws Exception {
-		logger.trace("reallyAccount()");
+	protected String getSQLInsertCommand(Record record) {
+		StringBuffer sql = new StringBuffer();
+		sql.append("INSERT INTO ");
+		sql.append(record.getRecordType()); // tableNme == RecordType
+		boolean first = true;
+		SortedSet<String> keys = new TreeSet<>(record.getRequiredFields());
+		StringBuffer values = new StringBuffer();
+		for(String key : keys) {
+			if(first) {
+				sql.append(" ");
+				values.append(" (");
+				first = false;
+			}else {
+				sql.append(",");
+				values.append(",");
+			}
+			sql.append(key);
+			values.append(record.getResourceProperty(key));
+			
+		}
+		sql.append(") VALUES");
+		sql.append(values);
+		sql.append(");");
+		return sql.toString();
 	}
 	
 	@Override
-	protected void accountWithFallback(Record... records) throws Exception {
-		logger.trace("accountWithFallback()");
-	}
-
-	@Override
-	public void close() throws Exception {
-		logger.trace("close()");
+	protected void reallyAccount(Record record) throws Exception {
+		logger.trace("reallyAccount()");
+		String sqlCommand = getSQLInsertCommand(record);
+		statement.executeUpdate(sqlCommand);
 	}
 
 	@Override
 	protected void clean() throws Exception {
-		logger.trace("closeAndClean()");
+		logger.trace("clean()");
 	}
 
 	@Override
 	protected void closeConnection() throws Exception {
 		logger.trace("closeConnection()");
+		statement.close();
+		connection.commit();
+		connection.close();
 	}
 
 	@Override
 	public boolean isConnectionActive() throws Exception {
-		return true;
+		return connection.isValid(300);
 	};
 
 }