NetworkIdentitySet.java revision 55a442e58262e253df965d652bd8219c8d1e72d3 
1/*
2 * Copyright (C) 2011 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
17package com.android.server.net;
18
19import android.net.NetworkIdentity;
20
21import java.io.DataInputStream;
22import java.io.DataOutputStream;
23import java.io.IOException;
24import java.util.HashSet;
25
26/**
27 * Identity of a {@code iface}, defined by the set of {@link NetworkIdentity}
28 * active on that interface.
29 *
30 * @hide
31 */
32public class NetworkIdentitySet extends HashSet<NetworkIdentity> implements
33        Comparable<NetworkIdentitySet> {
34    private static final int VERSION_INIT = 1;
35    private static final int VERSION_ADD_ROAMING = 2;
36    private static final int VERSION_ADD_NETWORK_ID = 3;
37
38    public NetworkIdentitySet() {
39    }
40
41    public NetworkIdentitySet(DataInputStream in) throws IOException {
42        final int version = in.readInt();
43        final int size = in.readInt();
44        for (int i = 0; i < size; i++) {
45            if (version <= VERSION_INIT) {
46                final int ignored = in.readInt();
47            }
48            final int type = in.readInt();
49            final int subType = in.readInt();
50            final String subscriberId = readOptionalString(in);
51            final String networkId;
52            if (version >= VERSION_ADD_NETWORK_ID) {
53                networkId = readOptionalString(in);
54            } else {
55                networkId = null;
56            }
57            final boolean roaming;
58            if (version >= VERSION_ADD_ROAMING) {
59                roaming = in.readBoolean();
60            } else {
61                roaming = false;
62            }
63
64            add(new NetworkIdentity(type, subType, subscriberId, networkId, false));
65        }
66    }
67
68    public void writeToStream(DataOutputStream out) throws IOException {
69        out.writeInt(VERSION_ADD_NETWORK_ID);
70        out.writeInt(size());
71        for (NetworkIdentity ident : this) {
72            out.writeInt(ident.getType());
73            out.writeInt(ident.getSubType());
74            writeOptionalString(out, ident.getSubscriberId());
75            writeOptionalString(out, ident.getNetworkId());
76            out.writeBoolean(ident.getRoaming());
77        }
78    }
79
80    private static void writeOptionalString(DataOutputStream out, String value) throws IOException {
81        if (value != null) {
82            out.writeByte(1);
83            out.writeUTF(value);
84        } else {
85            out.writeByte(0);
86        }
87    }
88
89    private static String readOptionalString(DataInputStream in) throws IOException {
90        if (in.readByte() != 0) {
91            return in.readUTF();
92        } else {
93            return null;
94        }
95    }
96
97    @Override
98    public int compareTo(NetworkIdentitySet another) {
99        if (isEmpty()) return -1;
100        if (another.isEmpty()) return 1;
101
102        final NetworkIdentity ident = iterator().next();
103        final NetworkIdentity anotherIdent = another.iterator().next();
104        return ident.compareTo(anotherIdent);
105    }
106}
107