| 1 | // Copyright 2013 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | package org.chromium.chrome.browser.identity; |
| 6 | |
| 7 | import com.google.common.annotations.VisibleForTesting; |
| 8 | |
| 9 | import java.util.HashMap; |
| 10 | import java.util.Map; |
| 11 | |
| 12 | /** |
| 13 | * Factory for setting and retrieving instances of {@link UniqueIdentificationGenerator}s. |
| 14 | * <p/> |
| 15 | * A generator must always be set for a generator type before it is asked for. A generator type |
| 16 | * is any string you want to use for your generator. It is typically defined as a public static |
| 17 | * field in the generator itself. |
| 18 | */ |
| 19 | public final class UniqueIdentificationGeneratorFactory { |
| 20 | private static final Object LOCK = new Object(); |
| 21 | private static final Map<String, UniqueIdentificationGenerator> GENERATOR_MAP = |
| 22 | new HashMap<String, UniqueIdentificationGenerator>(); |
| 23 | |
| 24 | private UniqueIdentificationGeneratorFactory() { |
| 25 | } |
| 26 | |
| 27 | /** |
| 28 | * Returns a UniqueIdentificationGenerator if it exists, else throws IllegalArgumentException. |
| 29 | * |
| 30 | * @param generatorType the generator type you want |
| 31 | * @return a unique ID generator |
| 32 | */ |
| 33 | public static UniqueIdentificationGenerator getInstance(String generatorType) { |
| 34 | synchronized (LOCK) { |
| 35 | if (!GENERATOR_MAP.containsKey(generatorType)) { |
| 36 | throw new IllegalArgumentException("Unknown generator type " + generatorType); |
| 37 | } |
| 38 | return GENERATOR_MAP.get(generatorType); |
| 39 | } |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * During startup of the application, and before any calls to |
| 44 | * {@link #getInstance(String)} you must add all supported generators |
| 45 | * to this factory. |
| 46 | * |
| 47 | * @param generatorType the type of generator this is. Must be a unique string. |
| 48 | * @param gen the generator. |
| 49 | * @param force if set to true, will override any existing generator for this type. Else |
| 50 | * discards calls where a generator exists. |
| 51 | */ |
| 52 | @VisibleForTesting |
| 53 | public static void registerGenerator(String generatorType, UniqueIdentificationGenerator gen, |
| 54 | boolean force) { |
| 55 | synchronized (LOCK) { |
| 56 | if (GENERATOR_MAP.containsKey(generatorType) && !force) { |
| 57 | return; |
| 58 | } |
| 59 | GENERATOR_MAP.put(generatorType, gen); |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | @VisibleForTesting |
| 64 | public static void clearGeneratorMapForTest() { |
| 65 | synchronized (LOCK) { |
| 66 | GENERATOR_MAP.clear(); |
| 67 | } |
| 68 | } |
| 69 | } |