1/*
2 * Copyright (C) 2010 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 dalvik.system.profiler;
18
19import java.io.IOException;
20
21/**
22 * The {@code ThreadSampler} interfaces allows a profiler to choose
23 * between portable and VM specific implementations of thread
24 * sampling.
25 */
26public interface ThreadSampler {
27
28    /**
29     * Used to specify the maximum stack depth to collect.
30     */
31    public void setDepth(int depth);
32
33    /**
34     * Return a stack trace for the current thread limited by the
35     * maximum depth specified by {@link #setDepth setDepth}. May
36     * return null if no sample is availble for the thread, which may
37     * happen in cases such as thread termination. The resulting array
38     * should be copied before the next call to {@code getStackTrace}
39     * if the caller wants to use the results, since the {@code
40     * ThreadSampler} may reuse the array. Note that the elements
41     * themselves are immutable and do not need to be copied.
42     */
43    public StackTraceElement[] getStackTrace(Thread thread);
44}
45