1 /*******************************************************************************
2 * Copyright (c) 2012, 2014 Ericsson
3 * Copyright (c) 2010, 2011 École Polytechnique de Montréal
4 * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com>
6 * All rights reserved. This program and the accompanying materials are
7 * made available under the terms of the Eclipse Public License v1.0 which
8 * accompanies this distribution, and is available at
9 * http://www.eclipse.org/legal/epl-v10.html
11 *******************************************************************************/
13 package org
.eclipse
.tracecompass
.statesystem
.core
.backend
;
16 import java
.io
.FileInputStream
;
17 import java
.io
.PrintWriter
;
18 import java
.util
.List
;
20 import org
.eclipse
.jdt
.annotation
.NonNull
;
21 import org
.eclipse
.jdt
.annotation
.Nullable
;
22 import org
.eclipse
.tracecompass
.statesystem
.core
.exceptions
.StateSystemDisposedException
;
23 import org
.eclipse
.tracecompass
.statesystem
.core
.exceptions
.TimeRangeException
;
24 import org
.eclipse
.tracecompass
.statesystem
.core
.interval
.ITmfStateInterval
;
25 import org
.eclipse
.tracecompass
.statesystem
.core
.statevalue
.ITmfStateValue
;
28 * The main difference between StateSystem and StateHistorySystem is that SHS
29 * allows 'seeking' back in time to reload a Current State at a previous time.
30 * "How to go back in time" is defined by the implementation of the
33 * A StateHistorySystem contains one and only one HistoryBackend. If you want to
34 * use a paradigm with more than one provider (eg. more or less precision
35 * depending on what's asked by the user), implement one wrapper HistoryBackend
36 * which can then contain your 2-3 other backends underneath.
38 * @author Alexandre Montplaisir
40 public interface IStateHistoryBackend
{
43 * Get the ID of the state system that populates this backend.
45 * @return The state system's ID.
48 @NonNull String
getSSID();
51 * Get the start time of this state history. This is usually the same as the
52 * start time of the originating trace.
54 * @return The start time
59 * Get the current end time of the state history. It will change as the
60 * history is being built.
62 * @return The end time
67 * Main method to insert state intervals into the history.
69 * @param stateStartTime
70 * The start time of the interval
72 * The end time of the interval
74 * The quark of the attribute this interval refers to
76 * The StateValue represented by this interval
77 * @throws TimeRangeException
78 * If the start or end time are invalid
80 // FIXME change to IStateInterval?
81 void insertPastState(long stateStartTime
, long stateEndTime
,
82 int quark
, @NonNull ITmfStateValue value
) throws TimeRangeException
;
85 * Indicate to the provider that we are done building the history (so it can
86 * close off, stop threads, etc.)
89 * The end time to assign to this state history. It could be
90 * farther in time than the last state inserted, for example.
91 * @throws TimeRangeException
92 * If the requested time makes no sense.
94 void finishedBuilding(long endTime
) throws TimeRangeException
;
97 * It is the responsibility of the backend to define where to save the
98 * Attribute Tree (since it's only useful to "reopen" an Attribute Tree if
99 * we have the matching History).
101 * This method defines where to read for the attribute tree when opening an
102 * already-existing history. Refer to the file format documentation.
104 * @return A FileInputStream object pointing to the correct file/location in
105 * the file where to read the attribute tree information.
107 FileInputStream
supplyAttributeTreeReader();
109 // FIXME change to FOS too?
111 * Supply the File object to which we will write the attribute tree. The
112 * position in this file is supplied by -TreeWriterFilePosition.
114 * @return The target File
116 File
supplyAttributeTreeWriterFile();
119 * Supply the position in the file where we should write the attribute tree
122 * @return The file position (we will seek() to it)
124 long supplyAttributeTreeWriterFilePosition();
127 * Delete any generated files or anything that might have been created by
128 * the history backend (either temporary or save files). By calling this, we
129 * return to the state as it was before ever building the history.
131 * You might not want to call automatically if, for example, you want an
132 * index file to persist on disk. This could be limited to actions
133 * originating from the user.
138 * Notify the state history back-end that the trace is being closed, so it
139 * should release its file descriptors, close its connections, etc.
143 // ------------------------------------------------------------------------
145 // ------------------------------------------------------------------------
148 * Complete "give me the state at a given time" method 'currentStateInfo' is
149 * an "out" parameter, that is, write to it the needed information and
150 * return. DO NOT 'new' currentStateInfo, it will be lost and nothing will
153 * @param currentStateInfo
154 * List of StateValues (index == quark) to fill up
156 * Target timestamp of the query
157 * @throws TimeRangeException
158 * If the timestamp is outside of the history/trace
159 * @throws StateSystemDisposedException
160 * If the state system is disposed while a request is ongoing.
162 void doQuery(@NonNull List
<@Nullable ITmfStateInterval
> currentStateInfo
, long t
)
163 throws TimeRangeException
, StateSystemDisposedException
;
166 * Some providers might want to specify a different way to obtain just a
167 * single StateValue instead of updating the whole list. If the method to
168 * use is the same, then feel free to just implement this as a wrapper using
172 * The target timestamp of the query.
173 * @param attributeQuark
174 * The single attribute for which you want the state interval
175 * @return The state interval matching this timestamp/attribute pair, or
176 * null if it was not found
177 * @throws TimeRangeException
178 * If the timestamp was invalid
179 * @throws StateSystemDisposedException
180 * If the state system is disposed while a request is ongoing.
182 ITmfStateInterval
doSingularQuery(long t
, int attributeQuark
)
183 throws TimeRangeException
, StateSystemDisposedException
;
186 * Debug method to print the contents of the history backend.
189 * The PrintWriter where to write the output
191 void debugPrint(PrintWriter writer
);