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 package com.android.tradefed.build; 17 18 import java.io.File; 19 import java.util.Collections; 20 import java.util.HashMap; 21 import java.util.Map; 22 23 /** 24 * A factory for creating {@link FileDownloadCache} 25 */ 26 public class FileDownloadCacheFactory { 27 28 // use the "singleton inner class" pattern 29 // http://en.wikipedia.org/wiki/Singleton_pattern#The_solution_of_Bill_Pugh 30 private static class SingletonHolder { 31 public static final FileDownloadCacheFactory INSTANCE = new FileDownloadCacheFactory(); 32 } 33 34 private Map<String, FileDownloadCache> mCacheObjectMap = Collections.synchronizedMap( 35 new HashMap<String, FileDownloadCache>()); 36 37 /** 38 * Get the singleton instance of FileDownloadCacheFactory 39 */ 40 public static FileDownloadCacheFactory getInstance() { 41 return SingletonHolder.INSTANCE; 42 } 43 44 /** 45 * Retrieve the {@link FileDownloadCache} with the given cache directory, creating if necessary. 46 * <p/> 47 * Note that the cache assumes that this process has exclusive access to the <var>cacheDir</var> 48 * directory. If multiple TF processes will be run on the same machine, they MUST each use 49 * unique cache directories. 50 * 51 * @param cacheDir the local filesystem directory to use as a cache 52 * @return the {@link FileDownloadCache} for given cacheDir 53 */ 54 public synchronized FileDownloadCache getCache(File cacheDir) { 55 FileDownloadCache cache = mCacheObjectMap.get(cacheDir.getAbsolutePath()); 56 if (cache == null) { 57 cache = new FileDownloadCache(cacheDir); 58 mCacheObjectMap.put(cacheDir.getAbsolutePath(), cache); 59 } 60 return cache; 61 } 62 } 63
