1 files changed, 175 insertions, 0 deletions
diff --git a/verigraph/src/main/java/it/polito/escape/verify/database/DatabaseClass.java b/verigraph/src/main/java/it/polito/escape/verify/database/DatabaseClass.java
new file mode 100644
index 0000000..7837e51
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+++ b/verigraph/src/main/java/it/polito/escape/verify/database/DatabaseClass.java
@@ -0,0 +1,175 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Politecnico di Torino and others.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Apache License, Version 2.0
+ * which accompanies this distribution, and is available at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *******************************************************************************/
+
+package it.polito.escape.verify.database;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import com.fasterxml.jackson.core.JsonGenerationException;
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.type.TypeFactory;
+
+import it.polito.escape.verify.exception.InternalServerErrorException;
+import it.polito.escape.verify.model.Graph;
+import it.polito.escape.verify.model.Neighbour;
+import it.polito.escape.verify.model.Node;
+import it.polito.escape.verify.service.GraphService;
+
+public class DatabaseClass {
+
+	private static final DatabaseClass				instance	= new DatabaseClass();
+
+	private static ConcurrentHashMap<Long, Graph>	graphs;
+
+	private static String							persistenceFile;
+
+	private static boolean							enablePersistence;
+
+	protected DatabaseClass() {
+		initialize();
+		if (enablePersistence)
+			loadDatabase();
+	}
+
+	private void initialize() {
+		graphs = new ConcurrentHashMap<>();
+		enablePersistence = false;
+		persistenceFile = System.getProperty("catalina.base") + "/webapps/verify/json/" + "database.json";
+	}
+
+	private void loadDatabase() {
+		ObjectMapper mapper = new ObjectMapper();
+
+		List<Graph> parsedGraphs = null;
+		try {
+			File databaseFile = new File(persistenceFile);
+			parsedGraphs = mapper.readValue(databaseFile,
+											TypeFactory.defaultInstance().constructCollectionType(	List.class,
+																									Graph.class));
+		}
+		catch (JsonParseException e) {
+			System.out.println("Database not loaded due to a JsonParseException: " + e.getMessage());
+			return;
+		}
+		catch (JsonMappingException e) {
+			System.out.println("Database not loaded due to a JsonMappingException: " + e.getMessage());
+			return;
+		}
+		catch (IOException e) {
+			//retry changing path
+			persistenceFile = "src/main/webapp/json/" + "database.json";
+
+			try {
+				File databaseFile = new File(persistenceFile);
+				parsedGraphs = mapper.readValue(databaseFile,
+						TypeFactory.defaultInstance().constructCollectionType(	List.class,
+								Graph.class));
+			} catch (JsonParseException e1) {
+				System.out.println("Database not loaded due to a JsonParseException: " + e.getMessage());
+				return;
+			} catch (JsonMappingException e1) {
+				System.out.println("Database not loaded due to a JsonMappingException: " + e.getMessage());
+				return;
+			} catch (IOException e1) {
+				System.out.println("Database not loaded due to an IOException: " + e.getMessage());
+				return;
+			}
+		}
+
+		System.out.println("Loading database...");
+
+		for (Graph graph : parsedGraphs) {
+
+			try {
+				GraphService.validateGraph(graph);
+			}
+			catch (Exception e) {
+				System.out.println("Invalid database file: at least one graph is invalid!");
+				return;
+			}
+
+			graph.setId(getNumberOfGraphs() + 1);
+
+			for (Map.Entry<Long, Node> nodeEntry : graph.getNodes().entrySet()) {
+				nodeEntry.getValue().setId(nodeEntry.getKey());
+
+				for (Map.Entry<Long, Neighbour> neighbourEntry : nodeEntry.getValue().getNeighbours().entrySet()) {
+					neighbourEntry.getValue().setId(neighbourEntry.getKey());
+				}
+			}
+
+			graphs.put(graph.getId(), graph);
+		}
+
+		System.out.println("Database loaded!");
+		System.out.println(graphs.size() + " graphs added");
+	}
+
+	public static DatabaseClass getInstance() {
+		return instance;
+	}
+
+	public ConcurrentHashMap<Long, Graph> getGraphs() {
+		return graphs;
+	}
+
+	public synchronized int getNumberOfGraphs() {
+		return graphs.size();
+	}
+
+	public synchronized int getGraphNumberOfNodes(long graphId) {
+		Graph graph = graphs.get(graphId);
+		if (graph == null)
+			return 0;
+		Map<Long, Node> nodes = graph.getNodes();
+		if (nodes == null)
+			return 0;
+		return nodes.size();
+	}
+
+	public static void persistDatabase() {
+		if (!enablePersistence)
+			return;
+		ObjectMapper mapper = new ObjectMapper();
+
+		try {
+			mapper.writeValue(new File(persistenceFile), graphs);
+		}
+		catch (JsonGenerationException e) {
+			throw new InternalServerErrorException("Unable to persist database due to a JsonGenerationException: "
+													+ e.getMessage());
+		}
+		catch (JsonMappingException e) {
+			throw new InternalServerErrorException("Unable to persist database due to a JsonMappingException: "
+													+ e.getMessage());
+		}
+		catch (IOException e) {
+			//retry changing path
+			persistenceFile = "src/main/webapp/json/" + "database.json";
+			try {
+				mapper.writeValue(new File(persistenceFile), graphs);
+			} catch (JsonGenerationException e1) {
+				throw new InternalServerErrorException("Unable to persist database due to a JsonGenerationException: "
+						+ e.getMessage());
+			} catch (JsonMappingException e1) {
+				throw new InternalServerErrorException("Unable to persist database due to a JsonGenerationException: "
+						+ e.getMessage());
+			} catch (IOException e1) {
+				throw new InternalServerErrorException("Unable to persist database due to an IOException: "
+						+ e.getMessage());
+			}
+		}
+	}
+}