use more general collections

src/main/java/io/github/danthe1st/arebac/data/commongraph/attributed/AttributedGraph.java

@@ -1,6 +1,6 @@
 package io.github.danthe1st.arebac.data.commongraph.attributed;
 
-import java.util.List;
+import java.util.Collection;
 
 /**
  * Interface for attributed graphs.
@@ -12,6 +12,6 @@
 public interface AttributedGraph<N extends AttributedNode, E extends AttributedGraphEdge<N>> {
 	N findNodeById(String id);
 
-	List<E> findOutgoingEdges(N node);
-	List<E> findIncomingEdges(N node);
+	Collection<E> findOutgoingEdges(N node);
+	Collection<E> findIncomingEdges(N node);
 }

src/main/java/io/github/danthe1st/arebac/data/commongraph/memory/CommonInMemoryGraph.java

@@ -1,7 +1,7 @@
 package io.github.danthe1st.arebac.data.commongraph.memory;
 
+import java.util.Collection;
 import java.util.HashSet;
-import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
@@ -17,11 +17,12 @@
  */
 public interface CommonInMemoryGraph<N extends CommonNode, E extends CommonEdge<N>> {
 	Map<String, N> nodes();
+
+	Map<N, ? extends Collection<E>> outgoingEdges();
 
-	Map<N, List<E>> outgoingEdges();
-	Map<N, List<E>> incomingEdges();
-
-	static <N extends CommonNode, E extends CommonEdge<N>> void validate(Map<String, N> nodes, Map<N, List<E>> outgoingEdges, Map<N, List<E>> incomingEdges) {
+	Map<N, ? extends Collection<E>> incomingEdges();
+
+	static <N extends CommonNode, E extends CommonEdge<N>> void validate(Map<String, N> nodes, Map<N, ? extends Collection<E>> outgoingEdges, Map<N, ? extends Collection<E>> incomingEdges) {
 		nodes.forEach((k, v) -> {
 			Objects.requireNonNull(k);
 			Objects.requireNonNull(v);
@@ -31,7 +32,7 @@ static <N extends CommonNode, E extends CommonEdge<N>> void validate(Map<String,
 		});
 		Set<E> allEdges = new HashSet<>();
 		for(N node : outgoingEdges.keySet()){
-			List<E> edges = outgoingEdges.get(node);
+			Collection<E> edges = outgoingEdges.get(node);
 			allEdges.addAll(edges);
 			for(E edge : edges){
 				if(!node.equals(edge.source())){
@@ -41,7 +42,7 @@ static <N extends CommonNode, E extends CommonEdge<N>> void validate(Map<String,
 		}
 		int incomingEdgeCount = 0;
 		for(N node : incomingEdges.keySet()){
-			List<E> edges = incomingEdges.get(node);
+			Collection<E> edges = incomingEdges.get(node);
 			incomingEdgeCount += edges.size();
 			for(E edge : edges){
 				if(!allEdges.contains(edge)){

src/main/java/io/github/danthe1st/arebac/data/graph_pattern/GPGraph.java

@@ -1,7 +1,7 @@
 package io.github.danthe1st.arebac.data.graph_pattern;
 
-import java.util.LinkedHashMap;
-import java.util.List;
+import java.util.Collection;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Function;
@@ -17,14 +17,14 @@
  * @see GraphPattern
  */
 public record GPGraph(Map<String, GPNode> nodes,
-		Map<GPNode, List<GPEdge>> outgoingEdges,
-		Map<GPNode, List<GPEdge>> incomingEdges) implements CommonInMemoryGraph<GPNode, GPEdge> {
+		Map<GPNode, Collection<GPEdge>> outgoingEdges,
+		Map<GPNode, Collection<GPEdge>> incomingEdges) implements CommonInMemoryGraph<GPNode, GPEdge> {
 
-	public GPGraph(List<GPNode> nodes, List<GPEdge> edges) {
+	public GPGraph(Collection<GPNode> nodes, Collection<GPEdge> edges) {
 		this(
 				nodes.stream().collect(Collectors.toMap(GPNode::id, Function.identity())),
-				edges.stream().collect(Collectors.groupingBy(GPEdge::source, LinkedHashMap::new, Collectors.toList())),
-				edges.stream().collect(Collectors.groupingBy(GPEdge::target, LinkedHashMap::new, Collectors.toList()))
+				edges.stream().collect(Collectors.groupingBy(GPEdge::source, Collectors.toCollection(HashSet::new))),
+				edges.stream().collect(Collectors.groupingBy(GPEdge::target, Collectors.toCollection(HashSet::new)))
 		);
 	}
 

src/main/java/io/github/danthe1st/arebac/data/graph_pattern/GraphPattern.java

@@ -1,5 +1,6 @@
 package io.github.danthe1st.arebac.data.graph_pattern;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -68,7 +69,7 @@ private static void checkGraphHasNode(GPGraph graph, GPNode node) {
 	}
 
 	private static void checkGraphHasEdge(GPGraph graph, GPEdge edge) {
-		List<GPEdge> edges = graph.outgoingEdges().get(edge.source());
+		Collection<GPEdge> edges = graph.outgoingEdges().get(edge.source());
 		if(edges == null){
 			throw new IllegalArgumentException("edge missing in graph: " + edge);
 		}

src/main/java/io/github/danthe1st/arebac/data/memory/InMemoryGraph.java

@@ -1,8 +1,10 @@
 package io.github.danthe1st.arebac.data.memory;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -44,12 +46,12 @@ public InMemoryGraphNode findNodeById(String id) {
 	}
 
 	@Override
-	public List<InMemoryGraphEdge> findOutgoingEdges(InMemoryGraphNode node) {
-		return Objects.requireNonNullElse(outgoingEdges().get(node), List.of());
+	public Collection<InMemoryGraphEdge> findOutgoingEdges(InMemoryGraphNode node) {
+		return Objects.requireNonNullElse(outgoingEdges().get(node), Set.of());
 	}
 
 	@Override
-	public List<InMemoryGraphEdge> findIncomingEdges(InMemoryGraphNode node) {
-		return Objects.requireNonNullElse(incomingEdges().get(node), List.of());
+	public Collection<InMemoryGraphEdge> findIncomingEdges(InMemoryGraphNode node) {
+		return Objects.requireNonNullElse(incomingEdges().get(node), Set.of());
 	}
 }

src/main/java/io/github/danthe1st/arebac/gpeval/GPEval.java

@@ -1,6 +1,7 @@
 package io.github.danthe1st.arebac.gpeval;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -279,7 +280,7 @@ private boolean forwardChecking(GPNode currentNode, Map<GPNode, Set<GPNode>> inc
 
 	private List<N> getNeighborsSatisfyingEdgeAndAttributeRequirements(GPNode currentNode, RelevantEdge relevantEdge) {
 		N currentNodeInDB = assignments.get(currentNode);
-		List<E> graphEdges;
+		Collection<E> graphEdges;
 		Function<E, N> neighborFinder;
 		if(relevantEdge.isOutgoing()){
 			graphEdges = graph.findOutgoingEdges(currentNodeInDB);
@@ -322,7 +323,7 @@ private boolean checkHasNecessaryEdges(GPNode node, N graphNode) {
 		);
 	}
 
-	private boolean checkNecessaryEdgesOneDirection(List<E> neighboringEdges, List<GPEdge> patternEdges, Function<E, N> edgeOtherNodeFinder, Function<GPEdge, GPNode> gpOtherNodeFinder) {
+	private boolean checkNecessaryEdgesOneDirection(Collection<E> neighboringEdges, Collection<GPEdge> patternEdges, Function<E, N> edgeOtherNodeFinder, Function<GPEdge, GPNode> gpOtherNodeFinder) {
 		for(GPEdge edge : Objects.requireNonNullElse(patternEdges, List.<GPEdge>of())){
 			boolean isSatisfied = false;
 			GPNode otherNode = gpOtherNodeFinder.apply(edge);
@@ -352,8 +353,8 @@ private boolean checkAttributeRequirements(List<AttributeRequirement> requiremen
 	}
 
 	private List<RelevantEdge> getRelevantEdges(GPNode currentNode) {
-		List<GPEdge> outgoingEdges = Objects.requireNonNullElse(pattern.graph().outgoingEdges().get(currentNode), List.of());
-		List<GPEdge> incomingEdges = Objects.requireNonNullElse(pattern.graph().incomingEdges().get(currentNode), List.of());
+		Collection<GPEdge> outgoingEdges = Objects.requireNonNullElse(pattern.graph().outgoingEdges().get(currentNode), Set.of());
+		Collection<GPEdge> incomingEdges = Objects.requireNonNullElse(pattern.graph().incomingEdges().get(currentNode), Set.of());
 
 		List<RelevantEdge> relevantEdges = new ArrayList<>();
 		for(GPEdge edge : incomingEdges){

src/main/java/io/github/danthe1st/arebac/weaving/Weaving.java

@@ -1,6 +1,7 @@
 package io.github.danthe1st.arebac.weaving;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
@@ -77,7 +78,7 @@ private LinkedHashMap<EdgeInGraphPattern, GPEdge> createEdges() {
 		LinkedHashMap<EdgeInGraphPattern, GPEdge> oldToNewEdges = new LinkedHashMap<>();
 		for(int patternId = 0; patternId < inputPatterns.size(); patternId++){
 			GraphPattern graphPattern = inputPatterns.get(patternId);
-			for(List<GPEdge> edgesOfNode : graphPattern.graph().incomingEdges().values()){
+			for(Collection<GPEdge> edgesOfNode : graphPattern.graph().incomingEdges().values()){
 				for(GPEdge oldEdgeInPattern : edgesOfNode){
 					EdgeInGraphPattern edgeInPattern = new EdgeInGraphPattern(patternId, oldEdgeInPattern);
 					GPEdge newEdge = convertEdge(edgeInPattern);

src/test/java/io/github/danthe1st/arebac/tests/gpeval/FriendOfFriendEvaluateTest.java

@@ -5,6 +5,7 @@
 import static io.github.danthe1st.arebac.data.graph_pattern.constraints.AttributeRequirementOperator.EQUAL;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -104,7 +105,7 @@ void evaluateGoodOutsiderFriends() {
 		Set<List<InMemoryGraphNode>> result = GPEval.evaluate(graph, pattern);
 		assertEquals(Set.of(List.of(connectorFriend)), result);
 	}
-	
+
 	@Test
 	void evaluateConnector() {
 		GraphPattern pattern = createFriendOfFriendPattern(connector.id());
@@ -118,7 +119,7 @@ void evaluateGoodConnectorFriends() {
 		Set<List<InMemoryGraphNode>> result = GPEval.evaluate(graph, pattern);
 		assertEquals(Set.of(), result);
 	}
-	
+
 	@Test
 	void evaluateCompletor() {
 		GraphPattern pattern = createFriendOfFriendPattern(triangleCompletor.id());
@@ -132,7 +133,7 @@ void evaluateGoodCompletorFriends() {
 		Set<List<InMemoryGraphNode>> result = GPEval.evaluate(graph, pattern);
 		assertEquals(Set.of(List.of(connectorFriend)), result);
 	}
-	
+
 	// adaptation from example 17 of https://doi.org/10.1145/3401027
 	private GraphPattern createFriendOfFriendPattern(String requestorId) {
 		GPNode requestor = new GPNode("requestor", USER_NODE_TYPE);
@@ -154,7 +155,7 @@ private GraphPattern createFriendOfFriendPattern(String requestorId) {
 				Map.of("requestor", requestor, FRIEND_EDGE_TYPE, friend, "friendOfFriend", friendOfFriend)
 		);
 	}
-	
+
 	private GraphPattern createGoodFriendOfFriendRequirement(String requestorId) {
 		GraphPattern friendOfFriendPattern = createFriendOfFriendPattern(requestorId);
 		Map<GPEdge, List<AttributeRequirement>> newEdgeRequirements =
@@ -163,7 +164,7 @@ private GraphPattern createGoodFriendOfFriendRequirement(String requestorId) {
 				.outgoingEdges()
 				.values()
 				.stream()
-				.flatMap(List::stream)
+					.flatMap(Collection::stream)
 					.collect(Collectors.toMap(e -> e, e -> List.of(new AttributeRequirement(GOOD_FRIEND_EDGE_ATTRIBUTE, EQUAL, attribute(true)))));
 		return new GraphPattern(friendOfFriendPattern.graph(), friendOfFriendPattern.mutualExclusionConstraints(), friendOfFriendPattern.nodeRequirements(), newEdgeRequirements, friendOfFriendPattern.returnedNodes(), friendOfFriendPattern.actorsToNodes());
 	}