Typify MultiValueMap and fix warnings in AutomaticRouter (eclipse-gef…

…#320)

The MultiValueMap used to be backed by a map with either a list or a
single object as value.

This part has been adapted so that the map always contains a list of
values. While this adds a small overhead when filling the map, it should
in return reduce the overhead when calling the getter for values with
only a single element.

Reduces the total amount of warnings by ~20.

org.eclipse.draw2d/src/org/eclipse/draw2d/AutomaticRouter.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2010 IBM Corporation and others.
+ * Copyright (c) 2000, 2023 IBM Corporation and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -12,7 +12,7 @@
  *******************************************************************************/
 package org.eclipse.draw2d;
 
-import java.util.ArrayList;
+import java.util.List;
 
 import org.eclipse.draw2d.geometry.Point;
 import org.eclipse.draw2d.geometry.PointList;
@@ -31,7 +31,7 @@
 public abstract class AutomaticRouter extends AbstractRouter {
 
 	private ConnectionRouter nextRouter;
-	private MultiValueMap connections = new MultiValueMap();
+	private final MultiValueMap<HashKey, Connection> connections = new MultiValueMap<>();
 
 	private static final class HashKey {
 
@@ -105,11 +105,11 @@ public void invalidate(Connection conn) {
 		if (conn.getSourceAnchor() == null || conn.getTargetAnchor() == null)
 			return;
 		HashKey connectionKey = new HashKey(conn);
-		ArrayList connectionList = connections.get(connectionKey);
+		List<Connection> connectionList = connections.get(connectionKey);
 		int affected = connections.remove(connectionKey, conn);
 		if (affected != -1) {
 			for (int i = affected; i < connectionList.size(); i++)
-				((Connection) connectionList.get(i)).revalidate();
+				connectionList.get(i).revalidate();
 		} else
 			connections.removeValue(conn);
 
@@ -133,11 +133,11 @@ public void remove(Connection conn) {
 		if (conn.getSourceAnchor() == null || conn.getTargetAnchor() == null)
 			return;
 		HashKey connectionKey = new HashKey(conn);
-		ArrayList connectionList = connections.get(connectionKey);
+		List<Connection> connectionList = connections.get(connectionKey);
 		if (connectionList != null) {
 			int index = connections.remove(connectionKey, conn);
 			for (int i = index + 1; i < connectionList.size(); i++)
-				((Connection) connectionList.get(i)).revalidate();
+				connectionList.get(i).revalidate();
 		}
 		if (next() != null)
 			next().remove(conn);
@@ -162,7 +162,7 @@ public void route(Connection conn) {
 		if (conn.getPoints().size() == 2) {
 			PointList points = conn.getPoints();
 			HashKey connectionKey = new HashKey(conn);
-			ArrayList connectionList = connections.get(connectionKey);
+			List<Connection> connectionList = connections.get(connectionKey);
 
 			if (connectionList != null) {
 

org.eclipse.draw2d/src/org/eclipse/draw2d/internal/MultiValueMap.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2010 IBM Corporation and others.
+ * Copyright (c) 2000, 2023 IBM Corporation and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -16,73 +16,48 @@
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 
-public class MultiValueMap {
-	private HashMap map = new HashMap();
+public class MultiValueMap<U, V> {
+	private final Map<U, List<V>> map = new HashMap<>();
 
-	public ArrayList get(Object key) {
-		Object value = map.get(key);
-		if (value == null)
-			return null;
-
-		if (value instanceof ArrayList)
-			return (ArrayList) value;
-		ArrayList v = new ArrayList(1);
-		v.add(value);
-		return v;
+	public List<V> get(Object key) {
+		return map.get(key);
 	}
 
-	public void put(Object key, Object value) {
-		Object existingValues = map.get(key);
-		if (existingValues == null) {
-			map.put(key, value);
-			return;
-		}
-		if (existingValues instanceof ArrayList v) {
-			if (!v.contains(value))
-				v.add(value);
-			return;
-		}
-		if (existingValues != value) {
-			ArrayList v = new ArrayList(2);
-			v.add(existingValues);
-			v.add(value);
-			map.put(key, v);
+	public void put(U key, V value) {
+		List<V> values = map.computeIfAbsent(key, ignored -> new ArrayList<>(1));
+		if (!values.contains(value)) {
+			values.add(value);
 		}
 	}
 
-	public int remove(Object key, Object value) {
-		Object existingValues = map.get(key);
-		if (existingValues != null) {
-			if (existingValues instanceof ArrayList v) {
-				int result = v.indexOf(value);
-				if (result == -1)
-					return -1;
-				v.remove(result);
-				if (v.isEmpty())
-					map.remove(key);
-				return result;
+	public int remove(U key, V value) {
+		List<V> values = map.get(key);
+		if (values != null) {
+			int position = values.indexOf(value);
+			if (position == -1) {
+				return -1;
 			}
-			if (map.remove(key) != null)
-				return 0;
+			values.remove(position);
+			if (values.isEmpty()) {
+				map.remove(key);
+			}
+			return position;
 		}
 		return -1;
 	}
 
-	public Object removeValue(Object value) {
-		Iterator iter = map.values().iterator();
-		Object current;
+	public V removeValue(V value) {
+		Iterator<List<V>> iter = map.values().iterator();
+		List<V> current;
 		while (iter.hasNext()) {
 			current = iter.next();
-			if (value.equals(current)) {
-				iter.remove();
-				return value;
-			} else if (current instanceof List) {
-				if (((List) current).remove(value)) {
-					if (((List) current).isEmpty())
-						iter.remove();
-					return value;
+			if (current.remove(value)) {
+				if (current.isEmpty()) {
+					iter.remove();
 				}
+				return value;
 			}
 		}
 		return null;