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

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