1 /*
2  * Copyright (C) 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.server.connectivity;
18 
19 import android.annotation.NonNull;
20 import android.annotation.Nullable;
21 import android.net.NetworkRequest;
22 
23 import java.util.Collection;
24 
25 /**
26  * A class that knows how to find the best network matching a request out of a list of networks.
27  */
28 public class NetworkRanker {
NetworkRanker()29     public NetworkRanker() { }
30 
31     /**
32      * Find the best network satisfying this request among the list of passed networks.
33      */
34     // Almost equivalent to Collections.max(nais), but allows returning null if no network
35     // satisfies the request.
36     @Nullable
getBestNetwork(@onNull final NetworkRequest request, @NonNull final Collection<NetworkAgentInfo> nais)37     public NetworkAgentInfo getBestNetwork(@NonNull final NetworkRequest request,
38             @NonNull final Collection<NetworkAgentInfo> nais) {
39         NetworkAgentInfo bestNetwork = null;
40         int bestScore = Integer.MIN_VALUE;
41         for (final NetworkAgentInfo nai : nais) {
42             if (!nai.satisfies(request)) continue;
43             if (nai.getCurrentScore() > bestScore) {
44                 bestNetwork = nai;
45                 bestScore = nai.getCurrentScore();
46             }
47         }
48         return bestNetwork;
49     }
50 }
51