1 /*******************************************************************************
2 * Copyright (c) 2012, 2013 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
.linuxtools
.statesystem
.core
.backend
;
16 import java
.io
.FileInputStream
;
17 import java
.io
.PrintWriter
;
18 import java
.util
.List
;
20 import org
.eclipse
.linuxtools
.statesystem
.core
.exceptions
.AttributeNotFoundException
;
21 import org
.eclipse
.linuxtools
.statesystem
.core
.exceptions
.StateSystemDisposedException
;
22 import org
.eclipse
.linuxtools
.statesystem
.core
.exceptions
.TimeRangeException
;
23 import org
.eclipse
.linuxtools
.statesystem
.core
.interval
.ITmfStateInterval
;
24 import org
.eclipse
.linuxtools
.statesystem
.core
.statevalue
.ITmfStateValue
;
27 * The main difference between StateSystem and StateHistorySystem is that SHS
28 * allows 'seeking' back in time to reload a Current State at a previous time.
29 * "How to go back in time" is defined by the implementation of the
32 * A StateHistorySystem contains one and only one HistoryBackend. If you want to
33 * use a paradigm with more than one provider (eg. more or less precision
34 * depending on what's asked by the user), implement one wrapper HistoryBackend
35 * which can then contain your 2-3 other backends underneath.
37 * @author Alexandre Montplaisir
40 public interface IStateHistoryBackend
{
43 * Get the start time of this state history. This is usually the same as the
44 * start time of the originating trace.
46 * @return The start time
51 * Get the current end time of the state history. It will change as the
52 * history is being built.
54 * @return The end time
59 * Main method to insert state intervals into the history.
61 * @param stateStartTime
62 * The start time of the interval
64 * The end time of the interval
66 * The quark of the attribute this interval refers to
68 * The StateValue represented by this interval
69 * @throws TimeRangeException
70 * If the start or end time are invalid
72 // FIXME change to IStateInterval?
73 void insertPastState(long stateStartTime
, long stateEndTime
,
74 int quark
, ITmfStateValue value
) throws TimeRangeException
;
77 * Indicate to the provider that we are done building the history (so it can
78 * close off, stop threads, etc.)
81 * The end time to assign to this state history. It could be
82 * farther in time than the last state inserted, for example.
83 * @throws TimeRangeException
84 * If the requested time makes no sense.
86 void finishedBuilding(long endTime
) throws TimeRangeException
;
89 * It is the responsibility of the backend to define where to save the
90 * Attribute Tree (since it's only useful to "reopen" an Attribute Tree if
91 * we have the matching History).
93 * This method defines where to read for the attribute tree when opening an
94 * already-existing history. Refer to the file format documentation.
96 * @return A FileInputStream object pointing to the correct file/location in
97 * the file where to read the attribute tree information.
99 FileInputStream
supplyAttributeTreeReader();
101 // FIXME change to FOS too?
103 * Supply the File object to which we will write the attribute tree. The
104 * position in this file is supplied by -TreeWriterFilePosition.
106 * @return The target File
108 File
supplyAttributeTreeWriterFile();
111 * Supply the position in the file where we should write the attribute tree
114 * @return The file position (we will seek() to it)
116 long supplyAttributeTreeWriterFilePosition();
119 * Delete any generated files or anything that might have been created by
120 * the history backend (either temporary or save files). By calling this, we
121 * return to the state as it was before ever building the history.
123 * You might not want to call automatically if, for example, you want an
124 * index file to persist on disk. This could be limited to actions
125 * originating from the user.
130 * Notify the state history back-end that the trace is being closed, so it
131 * should release its file descriptors, close its connections, etc.
135 // ------------------------------------------------------------------------
137 // ------------------------------------------------------------------------
140 * Complete "give me the state at a given time" method 'currentStateInfo' is
141 * an "out" parameter, that is, write to it the needed information and
142 * return. DO NOT 'new' currentStateInfo, it will be lost and nothing will
145 * @param currentStateInfo
146 * List of StateValues (index == quark) to fill up
148 * Target timestamp of the query
149 * @throws TimeRangeException
150 * If the timestamp is outside of the history/trace
151 * @throws StateSystemDisposedException
152 * If the state system is disposed while a request is ongoing.
154 void doQuery(List
<ITmfStateInterval
> currentStateInfo
, long t
)
155 throws TimeRangeException
, StateSystemDisposedException
;
158 * Some providers might want to specify a different way to obtain just a
159 * single StateValue instead of updating the whole list. If the method to
160 * use is the same, then feel free to just implement this as a wrapper using
164 * The target timestamp of the query.
165 * @param attributeQuark
166 * The single attribute for which you want the state interval
167 * @return The state interval matching this timestamp/attribute pair
168 * @throws TimeRangeException
169 * If the timestamp was invalid
170 * @throws AttributeNotFoundException
171 * If the quark was invalid
172 * @throws StateSystemDisposedException
173 * If the state system is disposed while a request is ongoing.
175 ITmfStateInterval
doSingularQuery(long t
, int attributeQuark
)
176 throws TimeRangeException
, AttributeNotFoundException
,
177 StateSystemDisposedException
;
180 * Simple check to make sure the requested timestamps are within the borders
181 * of this state history. This is used internally, but could also be used by
182 * the request sender (to check before sending in a lot of requests for
186 * The queried timestamp
187 * @return True if the timestamp is within range, false if not.
189 boolean checkValidTime(long t
);
192 * Debug method to print the contents of the history backend.
195 * The PrintWriter where to write the output
197 void debugPrint(PrintWriter writer
);