AbstractAsset.java revision 6a34bb2d6a6cbc7a70bdf0c53d238dc28e0b1d58 
1/*
2 * Copyright (C) 2015 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.statementservice.retriever;
18
19/**
20 * A handle representing the identity and address of some digital asset. An asset is an online
21 * entity that typically provides some service or content. Examples of assets are websites, Android
22 * apps, Twitter feeds, and Plus Pages.
23 *
24 * <p> Asset can be represented by a JSON string. For example, the web site https://www.google.com
25 * can be represented by
26 * <pre>
27 * {"namespace": "web", "site": "https://www.google.com"}
28 * </pre>
29 *
30 * <p> The Android app with package name com.google.test that is signed by a certificate with sha256
31 * fingerprint 11:22:33 can be represented by
32 * <pre>
33 * {"namespace": "android_app",
34 *  "package_name": "com.google.test",
35 *  "sha256_cert_fingerprints": ["11:22:33"]}
36 * </pre>
37 *
38 * <p>Given a signed APK, Java 7's commandline keytool can compute the fingerprint using:
39 * {@code keytool -list -printcert -jarfile signed_app.apk}
40 */
41public abstract class AbstractAsset {
42
43    /**
44     * Returns a JSON string representation of this asset. The strings returned by this function are
45     * normalized -- they can be used for equality testing.
46     */
47    public abstract String toJson();
48
49    /**
50     * Returns a key that can be used by {@link AbstractAssetMatcher} to lookup the asset.
51     *
52     * <p> An asset will match an {@code AssetMatcher} only if the value of this method is equal to
53     * {@code AssetMatcher.getMatchedLookupKey()}.
54     */
55    public abstract int lookupKey();
56
57    /**
58     * Creates a new Asset from its JSON string representation.
59     *
60     * @throws AssociationServiceException if the assetJson is not well formatted.
61     */
62    public static AbstractAsset create(String assetJson)
63            throws AssociationServiceException {
64        return AssetFactory.create(assetJson);
65    }
66}
67