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 UniqueIdentificationGeneratorFactory()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 */ getInstance(String generatorType)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 registerGenerator(String generatorType, UniqueIdentificationGenerator gen, boolean force)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 clearGeneratorMapForTest()64 public static void clearGeneratorMapForTest() { 65 synchronized (LOCK) { 66 GENERATOR_MAP.clear(); 67 } 68 } 69 } 70