sdk/sources/android-23/android/util/LocalLog.java

   1 /*
   2  * Copyright (C) 2006 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
  17 package android.util;
  18
  19 import java.io.FileDescriptor;
  20 import java.io.PrintWriter;
  21 import java.util.Calendar;
  22 import java.util.Iterator;
  23 import java.util.LinkedList;
  24
  25 /**
  26  * @hide
  27  */
  28 public final class LocalLog {
  29
  30     private LinkedList<String> mLog;
  31     private int mMaxLines;
  32     private long mNow;
  33
  34     public LocalLog(int maxLines) {
  35         mLog = new LinkedList<String>();
  36         mMaxLines = maxLines;
  37     }
  38
  39     public synchronized void log(String msg) {
  40         if (mMaxLines > 0) {
  41             mNow = System.currentTimeMillis();
  42             StringBuilder sb = new StringBuilder();
  43             Calendar c = Calendar.getInstance();
  44             c.setTimeInMillis(mNow);
  45             sb.append(String.format("%tm-%td %tH:%tM:%tS.%tL", c, c, c, c, c, c));
  46             mLog.add(sb.toString() + " - " + msg);
  47             while (mLog.size() > mMaxLines) mLog.remove();
  48         }
  49     }
  50
  51     public synchronized void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
  52         Iterator<String> itr = mLog.listIterator(0);
  53         while (itr.hasNext()) {
  54             pw.println(itr.next());
  55         }
  56     }
  57
  58     public synchronized void reverseDump(FileDescriptor fd, PrintWriter pw, String[] args) {
  59         for (int i = mLog.size() - 1; i >= 0; i--) {
  60             pw.println(mLog.get(i));
  61         }
  62     }
  63
  64     public static class ReadOnlyLocalLog {
  65         private final LocalLog mLog;
  66         ReadOnlyLocalLog(LocalLog log) {
  67             mLog = log;
  68         }
  69         public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
  70             mLog.dump(fd, pw, args);
  71         }
  72     }
  73
  74     public ReadOnlyLocalLog readOnlyLocalLog() {
  75         return new ReadOnlyLocalLog(this);
  76     }
  77 }