| 1 | /******************************************************************************* |
| 2 | * Copyright (c) 2012 Ericsson |
| 3 | * Copyright (c) 2010, 2011 École Polytechnique de Montréal |
| 4 | * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com> |
| 5 | * |
| 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 |
| 10 | * |
| 11 | *******************************************************************************/ |
| 12 | |
| 13 | package org.eclipse.linuxtools.internal.tmf.core.statesystem; |
| 14 | |
| 15 | import java.io.File; |
| 16 | import java.io.FileInputStream; |
| 17 | import java.io.PrintWriter; |
| 18 | import java.util.List; |
| 19 | |
| 20 | import org.eclipse.linuxtools.tmf.core.exceptions.AttributeNotFoundException; |
| 21 | import org.eclipse.linuxtools.tmf.core.exceptions.StateSystemDisposedException; |
| 22 | import org.eclipse.linuxtools.tmf.core.exceptions.TimeRangeException; |
| 23 | import org.eclipse.linuxtools.tmf.core.interval.ITmfStateInterval; |
| 24 | import org.eclipse.linuxtools.tmf.core.statevalue.ITmfStateValue; |
| 25 | |
| 26 | /** |
| 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 |
| 30 | * HistoryBackend. |
| 31 | * |
| 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. |
| 36 | * |
| 37 | * @author alexmont |
| 38 | * |
| 39 | */ |
| 40 | public interface IStateHistoryBackend { |
| 41 | |
| 42 | /** |
| 43 | * Get the start time of this state history. This is usually the same as the |
| 44 | * start time of the originating trace. |
| 45 | * |
| 46 | * @return The start time |
| 47 | */ |
| 48 | public long getStartTime(); |
| 49 | |
| 50 | /** |
| 51 | * Get the current end time of the state history. It will change as the |
| 52 | * history is being built. |
| 53 | * |
| 54 | * @return The end time |
| 55 | */ |
| 56 | public long getEndTime(); |
| 57 | |
| 58 | /** |
| 59 | * Main method to insert state intervals into the history. |
| 60 | * |
| 61 | * @param stateStartTime |
| 62 | * The start time of the interval |
| 63 | * @param stateEndTime |
| 64 | * The end time of the interval |
| 65 | * @param quark |
| 66 | * The quark of the attribute this interval refers to |
| 67 | * @param value |
| 68 | * The StateValue represented by this interval |
| 69 | * @throws TimeRangeException |
| 70 | * If the start or end time are invalid |
| 71 | */ |
| 72 | // FIXME change to IStateInterval? |
| 73 | public void insertPastState(long stateStartTime, long stateEndTime, |
| 74 | int quark, ITmfStateValue value) throws TimeRangeException; |
| 75 | |
| 76 | /** |
| 77 | * Indicate to the provider that we are done building the history (so it can |
| 78 | * close off, stop threads, etc.) |
| 79 | * |
| 80 | * @param endTime |
| 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. |
| 85 | */ |
| 86 | public void finishedBuilding(long endTime) throws TimeRangeException; |
| 87 | |
| 88 | /** |
| 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). |
| 92 | * |
| 93 | * This method defines where to read for the attribute tree when opening an |
| 94 | * already-existing history. Refer to the file format documentation. |
| 95 | * |
| 96 | * @return A FileInputStream object pointing to the correct file/location in |
| 97 | * the file where to read the attribute tree information. |
| 98 | */ |
| 99 | public FileInputStream supplyAttributeTreeReader(); |
| 100 | |
| 101 | // FIXME change to FOS too? |
| 102 | /** |
| 103 | * Supply the File object to which we will write the attribute tree. The |
| 104 | * position in this file is supplied by -TreeWriterFilePosition. |
| 105 | * |
| 106 | * @return The target File |
| 107 | */ |
| 108 | public File supplyAttributeTreeWriterFile(); |
| 109 | |
| 110 | /** |
| 111 | * Supply the position in the file where we should write the attribute tree |
| 112 | * when asked to. |
| 113 | * |
| 114 | * @return The file position (we will seek() to it) |
| 115 | */ |
| 116 | public long supplyAttributeTreeWriterFilePosition(); |
| 117 | |
| 118 | /** |
| 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. |
| 122 | * |
| 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. |
| 126 | */ |
| 127 | public void removeFiles(); |
| 128 | |
| 129 | /** |
| 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. |
| 132 | */ |
| 133 | public void dispose(); |
| 134 | |
| 135 | // ------------------------------------------------------------------------ |
| 136 | // Query methods |
| 137 | // ------------------------------------------------------------------------ |
| 138 | |
| 139 | /** |
| 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 |
| 143 | * be returned! |
| 144 | * |
| 145 | * @param currentStateInfo |
| 146 | * List of StateValues (index == quark) to fill up |
| 147 | * @param t |
| 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. |
| 153 | */ |
| 154 | public void doQuery(List<ITmfStateInterval> currentStateInfo, long t) |
| 155 | throws TimeRangeException, StateSystemDisposedException; |
| 156 | |
| 157 | /** |
| 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 |
| 161 | * doQuery(). |
| 162 | * |
| 163 | * @param t |
| 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. |
| 174 | */ |
| 175 | public ITmfStateInterval doSingularQuery(long t, int attributeQuark) |
| 176 | throws TimeRangeException, AttributeNotFoundException, |
| 177 | StateSystemDisposedException; |
| 178 | |
| 179 | /** |
| 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 |
| 183 | * example). |
| 184 | * |
| 185 | * @param t |
| 186 | * The queried timestamp |
| 187 | * @return True if the timestamp is within range, false if not. |
| 188 | */ |
| 189 | public boolean checkValidTime(long t); |
| 190 | |
| 191 | /** |
| 192 | * Debug method to print the contents of the history backend. |
| 193 | * |
| 194 | * @param writer |
| 195 | * The PrintWriter where to write the output |
| 196 | */ |
| 197 | public void debugPrint(PrintWriter writer); |
| 198 | } |