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
17package android.util;
18
19import java.io.FileDescriptor;
20import java.io.PrintWriter;
21import java.util.Calendar;
22import java.util.Iterator;
23import java.util.LinkedList;
24
25/**
26 * @hide
27 */
28public 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}
78