org.eclipse.linuxtools.tmf.core/src/org/eclipse/linuxtools/tmf/core/trace/ITmfTrace.java

   1 /*******************************************************************************
   2  * Copyright (c) 2009, 2013 Ericsson, École Polytechnique de Montréal
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Francois Chouinard - Initial API and implementation
  11  *   Francois Chouinard - Updated as per TMF Trace Model 1.0
  12  *   Geneviève Bastien  - Added timestamp transforms and timestamp
  13  *                        creation functions
  14  *******************************************************************************/
  15
  16 package org.eclipse.linuxtools.tmf.core.trace;
  17
  18 import java.util.Collections;
  19 import java.util.Map;
  20
  21 import org.eclipse.core.resources.IProject;
  22 import org.eclipse.core.resources.IResource;
  23 import org.eclipse.core.runtime.IStatus;
  24 import org.eclipse.linuxtools.tmf.core.component.ITmfDataProvider;
  25 import org.eclipse.linuxtools.tmf.core.event.ITmfEvent;
  26 import org.eclipse.linuxtools.tmf.core.exceptions.TmfTraceException;
  27 import org.eclipse.linuxtools.tmf.core.statesystem.ITmfStateSystem;
  28 import org.eclipse.linuxtools.tmf.core.statistics.ITmfStatistics;
  29 import org.eclipse.linuxtools.tmf.core.synchronization.ITmfTimestampTransform;
  30 import org.eclipse.linuxtools.tmf.core.timestamp.ITmfTimestamp;
  31 import org.eclipse.linuxtools.tmf.core.timestamp.TmfTimeRange;
  32 import org.eclipse.linuxtools.tmf.core.trace.indexer.ITmfTraceIndexer;
  33 import org.eclipse.linuxtools.tmf.core.trace.location.ITmfLocation;
  34
  35 /**
  36  * The event stream structure in TMF. In its basic form, a trace has:
  37  * <ul>
  38  * <li> an associated Eclipse resource
  39  * <li> a path to its location on the file system
  40  * <li> the type of the events it contains
  41  * <li> the number of events it contains
  42  * <li> the time range (span) of the events it contains
  43  * </ul>
  44  * Concrete ITmfTrace classes have to provide a parameter-less constructor and
  45  * an initialization method (<i>initTrace</i>) if they are to be opened from the
  46  * Project View. Also, a validation method (<i>validate</i>) has to be provided
  47  * to ensure that the trace is of the correct type.
  48  * <p>
  49  * A trace can be accessed simultaneously from multiple threads by various
  50  * application components. To avoid obvious multi-threading issues, the trace
  51  * uses an ITmfContext as a synchronization aid for its read operations.
  52  * <p>
  53  * A proper ITmfContext can be obtained by performing a seek operation on the
  54  * trace. Seek operations can be performed for a particular event (by rank or
  55  * timestamp) or for a plain trace location.
  56  * <p>
  57  * <b>Example 1</b>: Process a whole trace
  58  * <pre>
  59  * ITmfContext context = trace.seekEvent(0);
  60  * ITmfEvent event = trace.getNext(context);
  61  * while (event != null) {
  62  *     processEvent(event);
  63  *     event = trace.getNext(context);
  64  * }
  65  * </pre>
  66  * <b>Example 2</b>: Process 50 events starting from the 1000th event
  67  * <pre>
  68  * int nbEventsRead = 0;
  69  * ITmfContext context = trace.seekEvent(1000);
  70  * ITmfEvent event = trace.getNext(context);
  71  * while (event != null && nbEventsRead < 50) {
  72  *     nbEventsRead++;
  73  *     processEvent(event);
  74  *     event = trace.getNext(context);
  75  * }
  76  * </pre>
  77  * <b>Example 3</b>: Process the events between 2 timestamps (inclusive)
  78  * <pre>
  79  * ITmfTimestamp startTime = ...;
  80  * ITmfTimestamp endTime = ...;
  81  * ITmfContext context = trace.seekEvent(startTime);
  82  * ITmfEvent event = trace.getNext(context);
  83  * while (event != null && event.getTimestamp().compareTo(endTime) <= 0) {
  84  *     processEvent(event);
  85  *     event = trace.getNext(context);
  86  * }
  87  * </pre>
  88  *
  89  * A trace is also an event provider so it can process event requests
  90  * asynchronously (and coalesce compatible, concurrent requests).
  91  * <p>
  92  *
  93  * <b>Example 4</b>: Process a whole trace (see ITmfEventRequest for
  94  * variants)
  95  * <pre>
  96  * ITmfRequest request = new TmfEventRequest&lt;MyEventType&gt;(MyEventType.class) {
  97  *     &#064;Override
  98  *     public void handleData(MyEventType event) {
  99  *         super.handleData(event);
 100  *         processEvent(event);
 101  *     }
 102  *
 103  *     &#064;Override
 104  *     public void handleCompleted() {
 105  *         finish();
 106  *         super.handleCompleted();
 107  *     }
 108  * };
 109  *
 110  * fTrace.handleRequest(request);
 111  * if (youWant) {
 112  *     request.waitForCompletion();
 113  * }
 114  * </pre>
 115  *
 116  * @version 1.0
 117  * @author Francois Chouinard
 118  *
 119  * @see ITmfContext
 120  * @see ITmfEvent
 121  * @see ITmfTraceIndexer
 122  * @see ITmfEventParser
 123  */
 124 public interface ITmfTrace extends ITmfDataProvider {
 125
 126     // ------------------------------------------------------------------------
 127     // Constants
 128     // ------------------------------------------------------------------------
 129
 130     /**
 131      * The default trace cache size
 132      */
 133     public static final int DEFAULT_TRACE_CACHE_SIZE = 1000;
 134
 135     // ------------------------------------------------------------------------
 136     // Initializers
 137     // ------------------------------------------------------------------------
 138
 139     /**
 140      * Initialize a newly instantiated "empty" trace object. This is used to
 141      * properly parameterize an ITmfTrace instantiated with its parameterless
 142      * constructor.
 143      * <p>
 144      * Typically, the parameterless constructor will provide the block size and
 145      * its associated parser and indexer.
 146      *
 147      * @param resource
 148      *            the trace resource
 149      * @param path
 150      *            the trace path
 151      * @param type
 152      *            the trace event type
 153      * @throws TmfTraceException
 154      *             If we couldn't open the trace
 155      */
 156     void initTrace(IResource resource, String path, Class<? extends ITmfEvent> type) throws TmfTraceException;
 157
 158     /**
 159      * Validate that the trace is of the correct type.
 160      *
 161      * @param project
 162      *            the eclipse project
 163      * @param path
 164      *            the trace path
 165      * @return an IStatus object with validation result. Use severity OK to
 166      *         indicate success.
 167      * @since 2.0
 168      */
 169     IStatus validate(IProject project, String path);
 170
 171     // ------------------------------------------------------------------------
 172     // Basic getters
 173     // ------------------------------------------------------------------------
 174
 175     /**
 176      * @return the trace event type
 177      */
 178     Class<? extends ITmfEvent> getEventType();
 179
 180     /**
 181      * @return the associated trace resource
 182      */
 183     IResource getResource();
 184
 185     /**
 186      * @return the trace path
 187      */
 188     String getPath();
 189
 190     /**
 191      * @return the trace cache size
 192      */
 193     int getCacheSize();
 194
 195     /**
 196      * @return The statistics provider for this trace
 197      * @since 2.0
 198      */
 199     ITmfStatistics getStatistics();
 200
 201     /**
 202      * Return the map of state systems associated with this trace.
 203      *
 204      * This view should be read-only (implementations should use
 205      * {@link Collections#unmodifiableMap}).
 206      *
 207      * @return The map of state systems
 208      * @since 2.0
 209      */
 210     Map<String, ITmfStateSystem> getStateSystems();
 211
 212     /**
 213      * If a state system is not build by the trace itself, it's possible to
 214      * register it if it comes from another source. It will then be accessible
 215      * with {@link #getStateSystems} normally.
 216      *
 217      * @param id
 218      *            The unique ID to assign to this state system. In case of
 219      *            conflicting ID's, the new one will overwrite the previous one
 220      *            (default Map behavior).
 221      * @param ss
 222      *            The already-built state system
 223      * @since 2.0
 224      */
 225     void registerStateSystem(String id, ITmfStateSystem ss);
 226
 227     /**
 228      * Index the trace. Depending on the trace type, this could be done at the
 229      * constructor or initTrace phase too, so this could be implemented as a
 230      * no-op.
 231      *
 232      * @param waitForCompletion
 233      *            Should we block the caller until indexing is finished, or not.
 234      * @since 2.0
 235      */
 236     void indexTrace(boolean waitForCompletion);
 237
 238     // ------------------------------------------------------------------------
 239     // Trace characteristics getters
 240     // ------------------------------------------------------------------------
 241
 242     /**
 243      * @return the number of events in the trace
 244      */
 245     long getNbEvents();
 246
 247     /**
 248      * @return the trace time range
 249      * @since 2.0
 250      */
 251     TmfTimeRange getTimeRange();
 252
 253     /**
 254      * @return the timestamp of the first trace event
 255      * @since 2.0
 256      */
 257     ITmfTimestamp getStartTime();
 258
 259     /**
 260      * @return the timestamp of the last trace event
 261      * @since 2.0
 262      */
 263     ITmfTimestamp getEndTime();
 264
 265     /**
 266      * @return the streaming interval in ms (0 if not a streaming trace)
 267      */
 268     long getStreamingInterval();
 269
 270     // ------------------------------------------------------------------------
 271     // Trace positioning getters
 272     // ------------------------------------------------------------------------
 273
 274     /**
 275      * @return the current trace location
 276      * @since 3.0
 277      */
 278     ITmfLocation getCurrentLocation();
 279
 280     /**
 281      * Returns the ratio (proportion) corresponding to the specified location.
 282      *
 283      * @param location
 284      *            a trace specific location
 285      * @return a floating-point number between 0.0 (beginning) and 1.0 (end)
 286      * @since 3.0
 287      */
 288     double getLocationRatio(ITmfLocation location);
 289
 290     // ------------------------------------------------------------------------
 291     // SeekEvent operations (returning a trace context)
 292     // ------------------------------------------------------------------------
 293
 294     /**
 295      * Position the trace at the specified (trace specific) location.
 296      * <p>
 297      * A null location is interpreted as seeking for the first event of the
 298      * trace.
 299      * <p>
 300      * If not null, the location requested must be valid otherwise the returned
 301      * context is undefined (up to the implementation to recover if possible).
 302      * <p>
 303      *
 304      * @param location
 305      *            the trace specific location
 306      * @return a context which can later be used to read the corresponding event
 307      * @since 3.0
 308      */
 309     ITmfContext seekEvent(ITmfLocation location);
 310
 311     /**
 312      * Position the trace at the 'rank'th event in the trace.
 313      * <p>
 314      * A rank <= 0 is interpreted as seeking for the first event of the trace.
 315      * <p>
 316      * If the requested rank is beyond the last trace event, the context
 317      * returned will yield a null event if used in a subsequent read.
 318      *
 319      * @param rank
 320      *            the event rank
 321      * @return a context which can later be used to read the corresponding event
 322      */
 323     ITmfContext seekEvent(long rank);
 324
 325     /**
 326      * Position the trace at the first event with the specified timestamp. If
 327      * there is no event with the requested timestamp, a context pointing to the
 328      * next chronological event is returned.
 329      * <p>
 330      * A null timestamp is interpreted as seeking for the first event of the
 331      * trace.
 332      * <p>
 333      * If the requested timestamp is beyond the last trace event, the context
 334      * returned will yield a null event if used in a subsequent read.
 335      *
 336      * @param timestamp
 337      *            the timestamp of desired event
 338      * @return a context which can later be used to read the corresponding event
 339      * @since 2.0
 340      */
 341     ITmfContext seekEvent(ITmfTimestamp timestamp);
 342
 343     /**
 344      * Position the trace at the event located at the specified ratio in the
 345      * trace file.
 346      * <p>
 347      * The notion of ratio (0.0 <= r <= 1.0) is trace specific and left
 348      * voluntarily vague. Typically, it would refer to the event proportional
 349      * rank (arguably more intuitive) or timestamp in the trace file.
 350      *
 351      * @param ratio
 352      *            the proportional 'rank' in the trace
 353      * @return a context which can later be used to read the corresponding event
 354      */
 355     ITmfContext seekEvent(double ratio);
 356
 357     /**
 358      * Returns the initial range offset
 359      *
 360      * @return the initial range offset
 361      * @since 2.0
 362      */
 363     ITmfTimestamp getInitialRangeOffset();
 364
 365     /**
 366      * Returns the ID of the host this trace is from. The host ID is not
 367      * necessarily the hostname, but should be a unique identifier for the
 368      * machine on which the trace was taken. It can be used to determine if two
 369      * traces were taken on the exact same machine (timestamp are already
 370      * synchronized, resources with same id are the same if taken at the same
 371      * time, etc).
 372      *
 373      * @return The host id of this trace
 374      * @since 3.0
 375      */
 376     String getHostId();
 377
 378     // ------------------------------------------------------------------------
 379     // Timestamp transformation functions
 380     // ------------------------------------------------------------------------
 381
 382     /**
 383      * Returns the timestamp transformation for this trace
 384      *
 385      * @return the timestamp transform
 386      * @since 3.0
 387      */
 388     ITmfTimestampTransform getTimestampTransform();
 389
 390     /**
 391      * Sets the trace's timestamp transform
 392      *
 393      * @param tt
 394      *            The timestamp transform for all timestamps of this trace
 395      * @since 3.0
 396      */
 397     void setTimestampTransform(final ITmfTimestampTransform tt);
 398
 399     /**
 400      * Creates a timestamp for this trace, using the transformation formula
 401      *
 402      * @param ts
 403      *            The time in long with which to create the timestamp
 404      * @return The new timestamp
 405      * @since 3.0
 406      */
 407     ITmfTimestamp createTimestamp(long ts);
 408
 409 }