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
.tracecompass
.statesystem
.core
.exceptions
.AttributeNotFoundException
;
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.
47 @NonNull String
getSSID();
50 * Get the start time of this state history. This is usually the same as the
51 * start time of the originating trace.
53 * @return The start time
58 * Get the current end time of the state history. It will change as the
59 * history is being built.
61 * @return The end time
66 * Main method to insert state intervals into the history.
68 * @param stateStartTime
69 * The start time of the interval
71 * The end time of the interval
73 * The quark of the attribute this interval refers to
75 * The StateValue represented by this interval
76 * @throws TimeRangeException
77 * If the start or end time are invalid
79 // FIXME change to IStateInterval?
80 void insertPastState(long stateStartTime
, long stateEndTime
,
81 int quark
, ITmfStateValue value
) throws TimeRangeException
;
84 * Indicate to the provider that we are done building the history (so it can
85 * close off, stop threads, etc.)
88 * The end time to assign to this state history. It could be
89 * farther in time than the last state inserted, for example.
90 * @throws TimeRangeException
91 * If the requested time makes no sense.
93 void finishedBuilding(long endTime
) throws TimeRangeException
;
96 * It is the responsibility of the backend to define where to save the
97 * Attribute Tree (since it's only useful to "reopen" an Attribute Tree if
98 * we have the matching History).
100 * This method defines where to read for the attribute tree when opening an
101 * already-existing history. Refer to the file format documentation.
103 * @return A FileInputStream object pointing to the correct file/location in
104 * the file where to read the attribute tree information.
106 FileInputStream
supplyAttributeTreeReader();
108 // FIXME change to FOS too?
110 * Supply the File object to which we will write the attribute tree. The
111 * position in this file is supplied by -TreeWriterFilePosition.
113 * @return The target File
115 File
supplyAttributeTreeWriterFile();
118 * Supply the position in the file where we should write the attribute tree
121 * @return The file position (we will seek() to it)
123 long supplyAttributeTreeWriterFilePosition();
126 * Delete any generated files or anything that might have been created by
127 * the history backend (either temporary or save files). By calling this, we
128 * return to the state as it was before ever building the history.
130 * You might not want to call automatically if, for example, you want an
131 * index file to persist on disk. This could be limited to actions
132 * originating from the user.
137 * Notify the state history back-end that the trace is being closed, so it
138 * should release its file descriptors, close its connections, etc.
142 // ------------------------------------------------------------------------
144 // ------------------------------------------------------------------------
147 * Complete "give me the state at a given time" method 'currentStateInfo' is
148 * an "out" parameter, that is, write to it the needed information and
149 * return. DO NOT 'new' currentStateInfo, it will be lost and nothing will
152 * @param currentStateInfo
153 * List of StateValues (index == quark) to fill up
155 * Target timestamp of the query
156 * @throws TimeRangeException
157 * If the timestamp is outside of the history/trace
158 * @throws StateSystemDisposedException
159 * If the state system is disposed while a request is ongoing.
161 void doQuery(@NonNull List
<ITmfStateInterval
> currentStateInfo
, long t
)
162 throws TimeRangeException
, StateSystemDisposedException
;
165 * Some providers might want to specify a different way to obtain just a
166 * single StateValue instead of updating the whole list. If the method to
167 * use is the same, then feel free to just implement this as a wrapper using
171 * The target timestamp of the query.
172 * @param attributeQuark
173 * The single attribute for which you want the state interval
174 * @return The state interval matching this timestamp/attribute pair
175 * @throws TimeRangeException
176 * If the timestamp was invalid
177 * @throws AttributeNotFoundException
178 * If the quark 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
, AttributeNotFoundException
,
184 StateSystemDisposedException
;
187 * Debug method to print the contents of the history backend.
190 * The PrintWriter where to write the output
192 void debugPrint(PrintWriter writer
);