fixed problem with failed tests (and poor performance)

src/main/java/it/unibz/inf/isochrone/algorithm/Isochrone.java

@@ -22,7 +22,6 @@ import java.util.Map.Entry;
 import java.util.PriorityQueue;
 import java.util.Set;
 import java.util.function.Predicate;
-import java.util.stream.Collectors;
 
 /**
  * The Isochrone algorithm as described in the paper.  As the
@@ -34,6 +33,14 @@ import java.util.stream.Collectors;
  * algorithms which define the loading of the data from the database.
  */
 public abstract class Isochrone {
+	private static final Predicate<Link> PREDICATE_LINK_CONT = new Predicate<Link>() {
+		private final Double dMin = Double.MIN_VALUE;
+
+		@Override
+		public boolean test(final Link link) {
+			return link.isContinuous() && !dMin.equals(link.getStartOffset());
+		}
+	};
 	private final Collection<Integer> dateCodes;
 	private final AbstractQueue<Node> nodeQueue;
 	private final long qDuration;
@@ -170,16 +177,11 @@ public abstract class Isochrone {
 
 			cConnections = prepareContinuousLinks(node, links);
 			updateNodeQueue(expandContinuousLinks(cConnections));
-			output.addLinks(links.stream().filter(new Predicate<Link>() {
-				@Override
-				public boolean test(final Link link) {
-					return link.isContinuous();
-				}
-			}).collect(Collectors.toList()));
 
 			dConnections = prepareDiscreteLinks(node, links);
 			updateNodeQueue(expandDiscreteLinks(dConnections));
 
+			output.addLinks(links.parallelStream().filter(PREDICATE_LINK_CONT));
 			if (qIsExpiring && node.isExpired()) {
 				removeNode(nodeId);
 			}
@@ -229,7 +231,7 @@ public abstract class Isochrone {
 			}
 		} else {
 			nConnection.addLink(targetNode, link);
-	}
+		}
 	}
 
 	/**

src/main/java/it/unibz/inf/isochrone/db/Database.java

@@ -475,7 +475,13 @@ public class Database {
 				final short degree = rs.getShort("DEGREE");
 				final int targetId = rs.getInt("TARGET");
 
-				final Link link = new Link(linkId, sourceId, targetId, (rs.getByte("EDGE_MODE") == NW_MODE_CONTINUOUS) ? rs.getDouble("LENGTH") : rs.getShort("ROUTE_ID"));
+				Link link = null;
+				if (rs.getByte("EDGE_MODE") == NW_MODE_CONTINUOUS) {
+					link = new Link(linkId, sourceId, targetId, rs.getDouble("LENGTH"));
+				} else {
+					link = new Link(linkId, sourceId, targetId, rs.getShort("ROUTE_ID"));
+				}
+
 				addLink(addNodes(link, degree, nodes), link, adjList);
 			}
 		} catch (final SQLException e) {
@@ -501,6 +507,7 @@ public class Database {
 		try {
 			rs = stmt.executeQuery();
 			while (rs.next()) {
+				final int linkId = rs.getInt("ID");
 				final int startNodeId = rs.getInt("SOURCE");
 				final int endNodeId = rs.getInt("TARGET");
 
@@ -525,8 +532,12 @@ public class Database {
 					node.setAdjLinks(new ArrayList<Link>());
 				}
 
-				final int linkId = rs.getInt("ID");
-				final Link link = new Link(linkId, startNodeId, endNodeId, (rs.getByte("EDGE_MODE") == NW_MODE_CONTINUOUS) ? rs.getDouble("LENGTH") : rs.getShort("ROUTE_ID"));
+				final Link link;
+				if (rs.getByte("EDGE_MODE") == NW_MODE_CONTINUOUS) {
+					link = new Link(linkId, startNodeId, endNodeId, rs.getDouble("LENGTH"));
+				} else {
+					link = new Link(linkId, startNodeId, endNodeId, rs.getShort("ROUTE_ID"));
+				}
 				node.addAdjLink(link);
 				links.put(linkId, link);
 				if (!nodes.containsKey(start)) {
@@ -617,6 +628,8 @@ public class Database {
 	// Private methods
 
 	private Link createLinkFromResultSet(final int nodeId, final int adjNodeId, final ResultSet rs) throws SQLException {
+		final int linkId = rs.getInt("ID");
+
 		int start, end;
 		if (isIncoming) {
 			start = adjNodeId;
@@ -626,7 +639,14 @@ public class Database {
 			end = adjNodeId;
 		}
 
-		return new Link(rs.getInt("ID"), start, end, (rs.getByte("EDGE_MODE") == NW_MODE_CONTINUOUS) ? rs.getDouble("LENGTH") : rs.getShort("ROUTE_ID"));
+		final Link link;
+		if (rs.getByte("EDGE_MODE") == NW_MODE_CONTINUOUS) {
+			link = new Link(linkId, start, end, rs.getDouble("LENGTH"));
+		} else {
+			link = new Link(linkId, start, end, rs.getShort("ROUTE_ID"));
+		}
+
+		return link;
 	}
 
 	/**
@@ -755,7 +775,7 @@ public class Database {
 	 */
 	private static void addNode(final int nodeId, final short nrAdjLinks, final Map<Integer, Node> nodes) {
 		if (nodes == null) {
-			return;
+			return; // Just for safety
 		}
 
 		final Node node = nodes.get(nodeId);

src/main/java/it/unibz/inf/isochrone/network/AbstractOutput.java

 package it.unibz.inf.isochrone.network;
 
 import java.util.Collection;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
 
 public abstract class AbstractOutput implements IOutput {
+	private final Consumer<Link> linkConsumer = new Consumer<Link>() {
+		@Override
+		public void accept(final Link link) {
+			addLink(link);
+		}
+	};
+	private final Consumer<Node> nodeConsumer = new Consumer<Node>() {
+		@Override
+		public void accept(final Node node) {
+			addNode(node);
+		}
+	};
 
 	/**
 	 * This is called after all links and nodes are stored in this output.
@@ -22,10 +36,18 @@ public abstract class AbstractOutput implements IOutput {
 		}
 	}
 
+	public void addLinks(final Stream<Link> linkStream) {
+		linkStream.forEach(linkConsumer);
+	}
+
 	public void addNodes(final Collection<Node> nodes) {
 		for (final Node node : nodes) {
 			addNode(node);
 		}
 	}
 
+	public void addNodes(final Stream<Node> nodeStream) {
+		nodeStream.forEach(nodeConsumer);
+	}
+
 }

src/main/java/it/unibz/inf/isochrone/network/MemoryOutput.java

 package it.unibz.inf.isochrone.network;
 
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.HashSet;
+import java.util.LinkedHashSet;
 
 /**
  * A sample output class, which simply stores all nodes and returns if needed.
@@ -15,8 +14,8 @@ public class MemoryOutput extends AbstractOutput {
 	// Constructor
 
 	public MemoryOutput() {
-		links = new ArrayList<>();
-		nodes = new HashSet<>();
+		links = new LinkedHashSet<>();
+		nodes = new LinkedHashSet<>();
 	}
 
 	// Getter