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

   1 /*******************************************************************************
   2  * Copyright (c) 2009, 2011, 2012 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.io.FileNotFoundException;
  17
  18 import org.eclipse.core.resources.IProject;
  19 import org.eclipse.core.resources.IResource;
  20 import org.eclipse.linuxtools.tmf.core.component.ITmfDataProvider;
  21 import org.eclipse.linuxtools.tmf.core.event.ITmfEvent;
  22 import org.eclipse.linuxtools.tmf.core.event.ITmfTimestamp;
  23 import org.eclipse.linuxtools.tmf.core.event.TmfTimeRange;
  24
  25 /**
  26  * <b><u>ITmfTrace</u></b>
  27  * <p>
  28  * The event stream structure in TMF. In its basic form, a trace has:
  29  * <ul>
  30  * <li> the associated Eclipse resource
  31  * <li> the path to its location on the file system
  32  * <li> the type of the events it contains
  33  * <li> the number of events it contains
  34  * <li> the time range (span) of the events it contains
  35  * </ul>
  36  * Concrete ITmfTrace classes have to provide a parameter-less constructor and
  37  * an initialization method (initTace())if they are to be opened from the
  38  * Project View. Also, a validation (validate()) method has to be provided to
  39  * ensure that the trace is of the correct type.
  40  * <p>
  41  * A trace can be accessed simultaneously from multiple threads by various
  42  * application components. To avoid obvious multi-threading issues, the trace
  43  * uses an ITmfContext as a synchronization aid for its read operations.
  44  * <p>
  45  * A proper ITmfContext can be obtained by performing a seek operation on the
  46  * trace. Seek operations can be performed for a particular event (by rank or
  47  * timestamp) or for a plain trace location.
  48  * <p>
  49  * <b>Example 1</b>: Process a whole trace
  50  * <pre>
  51  * ITmfContext context = trace.seekLocationt(null);
  52  * ITmfEvent event = trace.getNextEvent(context);
  53  * while (event != null) {
  54  *     processEvent(event);
  55  *     event = trace.getNextEvent(context);
  56  * }
  57  * </pre>
  58  * <b>Example 2</b>: Process 50 events starting from the 1000th event
  59  * <pre>
  60  * int nbEventsRead = 0;
  61  * ITmfContext context = trace.seekEvent(1000);
  62  * ITmfEvent event = trace.getNextEvent(context);
  63  * while (event != null && nbEventsRead < 50) {
  64  *     nbEventsRead++;
  65  *     processEvent(event);
  66  *     event = trace.getNextEvent(context);
  67  * }
  68  * </pre>
  69  * <b>Example 3</b>: Process the events between 2 timestamps (inclusive)
  70  * <pre>
  71  * ITmfTimestamp startTime = ...;
  72  * ITmfTimestamp endTime = ...;
  73  * ITmfContext context = trace.seekEvent(startTime);
  74  * ITmfEvent event = trace.getNextEvent(context);
  75  * while (event != null && event.getTimestamp().compareTo(endTime) <= 0) {
  76  *     processEvent(event);
  77  *     event = trace.getNextEvent(context);
  78  * }
  79  * </pre>
  80  * A trace is also an event provider so it can process event requests
  81  * asynchronously (and coalesce compatible requests).
  82  * <p>
  83  * </pre>
  84  * <b>Example 4</b>: Process a whole trace
  85  * <pre>
  86  * ITmfRequest request = new TmfEventRequest&lt;MyEventType&gt;(MyEventType.class) {
  87  *     &#64;Override
  88  *     public void handleData(MyEventType event) {
  89  *         super.handleData(event);
  90  *         processEvent(event);
  91  *     }
  92  *     &#64;Override
  93  *     public void handleCompleted() {
  94  *         finish();
  95  *         super.handleCompleted();
  96  *     }
  97  * };
  98  * fTrace.handleRequest(request);
  99  * if (youWant) {
 100  *     request.waitForCompletion();
 101  * }
 102  * </pre>
 103  * @see ITmfEvent
 104  * @see ITmfEventProvider
 105  * @see ITmfRequest
 106  */
 107 public interface ITmfTrace<T extends ITmfEvent> extends ITmfDataProvider<T> {
 108
 109     // ------------------------------------------------------------------------
 110     // Initializers
 111     // ------------------------------------------------------------------------
 112
 113     /**
 114      * Initialize a newly instantiated "empty" trace object. This is used to
 115      * properly parameterize an ITmfTrace instantiated with its parameterless
 116      * constructor.
 117      * <p>
 118      * Typically, the parameterless constructor will provide the block size
 119      * and its associated parser and indexer.
 120      *
 121      * @param resource the trace resource
 122      * @param path the trace path
 123      * @param type the trace event type
 124      * @throws FileNotFoundException
 125      */
 126     public void initTrace(IResource resource, String path, Class<T> type) throws FileNotFoundException;
 127
 128     /**
 129      * Validate that the trace is of the correct type.
 130      *
 131      * @param project the eclipse project
 132      * @param path the trace path
 133      *
 134      * @return true if trace is valid
 135      */
 136     public boolean validate(IProject project, String path);
 137
 138     // ------------------------------------------------------------------------
 139     // Basic getters
 140     // ------------------------------------------------------------------------
 141
 142     /**
 143      * @return the trace event type
 144      */
 145     public Class<T> getType();
 146
 147     /**
 148      * @return the associated trace resource
 149      */
 150     public IResource getResource();
 151
 152     /**
 153      * @return the trace path
 154      */
 155     public String getPath();
 156
 157     /**
 158      * @return the trace cache size
 159      */
 160     public int getCacheSize();
 161
 162     // ------------------------------------------------------------------------
 163     // Trace characteristics getters
 164     // ------------------------------------------------------------------------
 165
 166     /**
 167      * @return the number of events in the trace
 168      */
 169     public long getNbEvents();
 170
 171     /**
 172      * @return the trace time range
 173      */
 174     public TmfTimeRange getTimeRange();
 175
 176     /**
 177      * @return the timestamp of the first trace event
 178      */
 179     public ITmfTimestamp getStartTime();
 180
 181     /**
 182      * @return the timestamp of the last trace event
 183      */
 184     public ITmfTimestamp getEndTime();
 185
 186     // ------------------------------------------------------------------------
 187     // Trace positioning getters
 188     // ------------------------------------------------------------------------
 189
 190     /**
 191      * @return the current trace location
 192      */
 193     public ITmfLocation<?> getCurrentLocation();
 194
 195     /**
 196      * Returns the ratio (proportion) corresponding to the specified location.
 197      *
 198      * @param location a trace specific location
 199      * @return a floating-point number between 0.0 (beginning) and 1.0 (end)
 200      */
 201     public double getLocationRatio(ITmfLocation<?> location);
 202
 203     // ------------------------------------------------------------------------
 204     // Seek operations (returning a reading context)
 205     // ------------------------------------------------------------------------
 206
 207     /**
 208      * Position the trace at the specified location. The null location
 209      * is used to indicate that the first trace event is requested.
 210      * <p>
 211      * <ul>
 212      * <li> a <b>null</b> location returns the context of the first event
 213      * <li> an invalid location, including beyond the last event, returns a null context
 214      * </ul>
 215      * <p>
 216      * @param location the trace specific location (null for 1st event)
 217      * @return a context which can later be used to read the corresponding event
 218      */
 219     public ITmfContext seekLocation(ITmfLocation<?> location);
 220
 221     /**
 222      * Position the trace at the event located at the specified ratio in the
 223      * trace file.
 224      * <p>
 225      * The notion of ratio (0.0 <= r <= 1.0) is trace specific and left
 226      * voluntarily vague. Typically, it would refer to the event proportional
 227      * rank (arguably more intuitive) or timestamp in the trace file.
 228      *
 229      * @param ratio the proportional 'rank' in the trace
 230      * @return a context which can later be used to read the corresponding event
 231      */
 232     public ITmfContext seekLocation(double ratio);
 233
 234     /**
 235      * Position the trace at the first event with the specified timestamp. If
 236      * there is no event with the requested timestamp, a context pointing to
 237      * the next chronological event is returned.
 238      * <p>
 239      * A null timestamp is interpreted as seeking for the first event of the
 240      * trace.
 241      * <p>
 242      * If the requested timestamp is beyond the last trace event, the context
 243      * returned will yield a null event if used in a subsequent read.
 244      *
 245      * @param timestamp the timestamp of desired event
 246      * @return a context which can later be used to read the corresponding event
 247      */
 248     public ITmfContext seekEvent(ITmfTimestamp timestamp);
 249
 250     /**
 251      * Position the trace at the 'rank'th event in the trace.
 252      * <p>
 253      * If the requested rank is beyond the last trace event, the context
 254      * returned will yield a null event if used in a subsequent read.
 255      *
 256      * @param rank the event rank
 257      * @return a context which can later be used to read the corresponding event
 258      */
 259     public ITmfContext seekEvent(long rank);
 260
 261     // ------------------------------------------------------------------------
 262     // Read operations (returning an actual event)
 263     // ------------------------------------------------------------------------
 264
 265     /**
 266      * Return the event pointed by the supplied context (or null if no event
 267      * left) and updates the context to point the next event.
 268      *
 269      * @param context the read context (will be updated)
 270      * @return the event pointed to by the context
 271      */
 272     public ITmfEvent getNextEvent(ITmfContext context);
 273
 274     /**
 275      * Return the event pointed by the supplied context (or null if no event
 276      * left) and *does not* update the context.
 277      *
 278      * @param context the read context
 279      * @return the next event in the stream
 280      */
 281     public ITmfEvent parseEvent(ITmfContext context);
 282
 283     // ------------------------------------------------------------------------
 284     // ------------------------------------------------------------------------
 285
 286     /**
 287      * @return the streaming interval in ms (0 if not a streaming trace)
 288      */
 289     public long getStreamingInterval();
 290
 291 }