Tools/Source/Common/org/tianocore/common/cache/FileTimeStamp.java

   1 /** @file
   2 This file is to define the FileTimeStamp class for speeding up the dependency check.
   3
   4 Copyright (c) 2006, Intel Corporation
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14 package org.tianocore.common.cache;
  15
  16 import java.io.File;
  17 import java.util.Map;
  18 import java.util.TreeMap;
  19 import java.util.HashMap;
  20
  21 /**
  22    FileTimeStamp class is used to cache the time stamp of accessing file, which
  23    will speed up the dependency check for build
  24  **/
  25 public class FileTimeStamp {
  26     //
  27     // cache the modified timestamp of files accessed, to speed up the depencey check
  28     //
  29     private static Map<String, Long> timeStampCache = new HashMap<String, Long>();
  30
  31     /**
  32        Get the time stamp of given file. It will try the cache first and then
  33        get from file system if no time stamp of the file is cached.
  34
  35        @param file      File name
  36
  37        @return long     The time stamp of the file
  38      **/
  39     synchronized public static long get(String file) {
  40         long timeStamp = 0;
  41
  42         Long value = timeStampCache.get(file);
  43         if (value != null) {
  44             timeStamp = value.longValue();
  45         } else {
  46             timeStamp = new File(file).lastModified();
  47             timeStampCache.put(file, new Long(timeStamp));
  48         }
  49
  50         return timeStamp;
  51     }
  52
  53     /**
  54        Force update the time stamp for the given file
  55
  56        @param file          File name
  57        @param timeStamp     The time stamp of the file
  58      **/
  59     synchronized public static void update(String file, long timeStamp) {
  60         timeStampCache.put(file, new Long(timeStamp));
  61     }
  62
  63     /**
  64        Force update the time stamp for the given file
  65
  66        @param file          File name
  67      **/
  68     synchronized public static void update(String file) {
  69         long timeStamp = new File(file).lastModified();
  70         timeStampCache.put(file, new Long(timeStamp));
  71     }
  72
  73     /**
  74        Check if the time stamp of given file has been cached for not
  75
  76        @param file      The file name
  77
  78        @return boolean
  79      **/
  80     synchronized public static boolean containsKey(String file) {
  81         return timeStampCache.containsKey(file);
  82     }
  83 }