org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/HistogramDataModel.java

   1 /*******************************************************************************
   2  * Copyright (c) 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  *   Bernd Hufmann - Implementation of new interfaces/listeners and support for
  12  *                   time stamp in any order
  13  *   Francois Chouinard - Moved from LTTng to TMF
  14  *******************************************************************************/
  15
  16 package org.eclipse.linuxtools.tmf.ui.views.histogram;
  17
  18 import java.util.Arrays;
  19
  20 import org.eclipse.core.runtime.ListenerList;
  21
  22 /**
  23  * <b><u>HistogramDataModel</u></b>
  24  * <p>
  25  * Histogram-independent data model with the following characteristics:
  26  * <ul>
  27  * <li>The <i>basetime</i> is the timestamp of the first event
  28  * <li>There is a fixed number (<i>n</i>) of buckets of uniform duration
  29  * (<i>d</i>)
  30  * <li>The <i>timespan</i> of the model is thus: <i>n</i> * <i>d</i> time units
  31  * <li>Bucket <i>i</i> holds the number of events that occurred in time range:
  32  * [<i>basetime</i> + <i>i</i> * <i>d</i>, <i>basetime</i> + (<i>i</i> + 1) *
  33  * <i>d</i>)
  34  * </ul>
  35  * Initially, the bucket durations is set to 1ns. As the events are read, they
  36  * are tallied (using <i>countEvent()</i>) in the appropriate bucket (relative
  37  * to the <i>basetime</i>).
  38  * <p>
  39  * Eventually, an event will have a timestamp that exceeds the <i>timespan</i>
  40  * high end (determined by <i>n</i>, the number of buckets, and <i>d</i>, the
  41  * bucket duration). At this point, the histogram needs to be compacted. This is
  42  * done by simply merging adjacent buckets by pair, in effect doubling the
  43  * <i>timespan</i> (<i>timespan'</i> = <i>n</i> * <i>d'</i>, where <i>d'</i> =
  44  * 2<i>d</i>). This compaction happens as needed as the trace is read.
  45  * <p>
  46  * The model allows for timestamps in not increasing order. The timestamps can
  47  * be fed to the model in any order. If an event has a timestamp less than the
  48  * <i>basetime</i>, the buckets will be moved to the right to account for the
  49  * new smaller timestamp. The new <i>basetime</i> is a multiple of the bucket
  50  * duration smaller then the previous <i>basetime</i>. Note that the <i>basetime</i>
  51  * might not be anymore a timestamp of an event. If necessary, the buckets will
  52  * be compacted before moving to the right. This might be necessary to not
  53  * loose any event counts at the end of the buckets array.
  54  * <p>
  55  * The mapping from the model to the UI is performed by the <i>scaleTo()</i>
  56  * method. By keeping the number of buckets <i>n</i> relatively large with
  57  * respect to to the number of pixels in the actual histogram, we should achieve
  58  * a nice result when visualizing the histogram.
  59  * <p>
  60  * TODO: Add filter support for more refined event counting (e.g. by trace,
  61  * event type, etc.)
  62  * <p>
  63  * TODO: Cut-off eccentric values? TODO: Support for going back in time?
  64  */
  65 public class HistogramDataModel implements IHistogramDataModel {
  66
  67     // ------------------------------------------------------------------------
  68     // Constants
  69     // ------------------------------------------------------------------------
  70
  71     // The default number of buckets
  72     public static final int DEFAULT_NUMBER_OF_BUCKETS = 16 * 1000;
  73
  74     public static final int REFRESH_FREQUENCY = DEFAULT_NUMBER_OF_BUCKETS;
  75
  76     // ------------------------------------------------------------------------
  77     // Attributes
  78     // ------------------------------------------------------------------------
  79
  80     // Bucket management
  81     private final int fNbBuckets;
  82     private final long[] fBuckets;
  83     private long fBucketDuration;
  84     private long fNbEvents;
  85     private int fLastBucket;
  86
  87     // Timestamps
  88     private long fFirstBucketTime; // could be negative when analyzing events with descending order!!!
  89     private long fFirstEventTime;
  90     private long fLastEventTime;
  91     private long fCurrentEventTime;
  92     private long fTimeLimit;
  93
  94     // Private listener lists
  95     private final ListenerList fModelListeners;
  96
  97     // ------------------------------------------------------------------------
  98     // Constructors
  99     // ------------------------------------------------------------------------
 100
 101     public HistogramDataModel() {
 102         this(DEFAULT_NUMBER_OF_BUCKETS);
 103     }
 104
 105     public HistogramDataModel(int nbBuckets) {
 106         fNbBuckets = nbBuckets;
 107         fBuckets = new long[nbBuckets];
 108         fModelListeners = new ListenerList();
 109         clear();
 110     }
 111
 112     public HistogramDataModel(HistogramDataModel other) {
 113         fNbBuckets = other.fNbBuckets;
 114         fBuckets = Arrays.copyOf(other.fBuckets, fNbBuckets);
 115         fBucketDuration = other.fBucketDuration;
 116         fNbEvents = other.fNbEvents;
 117         fLastBucket = other.fLastBucket;
 118         fFirstBucketTime = other.fFirstBucketTime;
 119         fFirstEventTime = other.fFirstEventTime;
 120         fLastEventTime = other.fLastEventTime;
 121         fCurrentEventTime = other.fCurrentEventTime;
 122         fTimeLimit = other.fTimeLimit;
 123         fModelListeners = new ListenerList();
 124         Object[] listeners = other.fModelListeners.getListeners();
 125         for (Object listener : listeners) {
 126             fModelListeners.add(listener);
 127         }
 128     }
 129
 130     // ------------------------------------------------------------------------
 131     // Accessors
 132     // ------------------------------------------------------------------------
 133
 134     public long getNbEvents() {
 135         return fNbEvents;
 136     }
 137
 138     public int getNbBuckets() {
 139         return fNbBuckets;
 140     }
 141
 142     public long getBucketDuration() {
 143         return fBucketDuration;
 144     }
 145
 146     public long getFirstBucketTime() {
 147         return fFirstBucketTime;
 148     }
 149
 150     public long getStartTime() {
 151         return fFirstEventTime;
 152     }
 153
 154     public long getEndTime() {
 155         return fLastEventTime;
 156     }
 157
 158     public long getCurrentEventTime() {
 159         return fCurrentEventTime;
 160     }
 161
 162     public long getTimeLimit() {
 163         return fTimeLimit;
 164     }
 165
 166     // ------------------------------------------------------------------------
 167     // Listener handling
 168     // ------------------------------------------------------------------------
 169
 170     public void addHistogramListener(IHistogramModelListener listener) {
 171         fModelListeners.add(listener);
 172     }
 173
 174     public void removeHistogramListener(IHistogramModelListener listener) {
 175         fModelListeners.remove(listener);
 176     }
 177
 178     private void fireModelUpdateNotification() {
 179         fireModelUpdateNotification(0);
 180     }
 181
 182     private void fireModelUpdateNotification(long count) {
 183         if (count % REFRESH_FREQUENCY == 0) {
 184             Object[] listeners = fModelListeners.getListeners();
 185             for (int i = 0; i < listeners.length; i++) {
 186                 IHistogramModelListener listener = (IHistogramModelListener) listeners[i];
 187                 listener.modelUpdated();
 188             }
 189         }
 190     }
 191
 192     // ------------------------------------------------------------------------
 193     // Operations
 194     // ------------------------------------------------------------------------
 195
 196     @Override
 197     public void complete() {
 198         fireModelUpdateNotification();
 199     }
 200
 201     /**
 202      * Clear the histogram model.
 203      */
 204     @Override
 205     public void clear() {
 206         Arrays.fill(fBuckets, 0);
 207         fNbEvents = 0;
 208         fFirstBucketTime = 0;
 209         fLastEventTime = 0;
 210         fCurrentEventTime = 0;
 211         fLastBucket = 0;
 212         fBucketDuration = 1; // 1ns
 213         updateEndTime();
 214         fireModelUpdateNotification();
 215     }
 216
 217     /**
 218      * Sets the current event time
 219      *
 220      * @param timestamp
 221      */
 222     public void setCurrentEvent(long timestamp) {
 223         fCurrentEventTime = timestamp;
 224     }
 225
 226     /**
 227      * Sets the current event time
 228      *
 229      * @param timestamp
 230      */
 231     public void setCurrentEventNotifyListeners(long timestamp) {
 232         fCurrentEventTime = timestamp;
 233         fireModelUpdateNotification();
 234     }
 235
 236     /**
 237      * Add event to the correct bucket, compacting the if needed.
 238      *
 239      * @param timestamp the timestamp of the event to count
 240      */
 241     @Override
 242     public void countEvent(long eventCount, long timestamp) {
 243
 244         // Validate
 245         if (timestamp < 0) {
 246             return;
 247         }
 248
 249         // Set the start/end time if not already done
 250         if (fLastBucket == 0 && fBuckets[0] == 0 && timestamp > 0) {
 251             fFirstBucketTime = timestamp;
 252             fFirstEventTime = timestamp;
 253             updateEndTime();
 254         }
 255
 256         if (timestamp < fFirstEventTime) {
 257             fFirstEventTime = timestamp;
 258         }
 259
 260         if (fLastEventTime < timestamp) {
 261             fLastEventTime = timestamp;
 262         }
 263
 264         if (timestamp >= fFirstBucketTime) {
 265
 266             // Compact as needed
 267             while (timestamp >= fTimeLimit) {
 268                 mergeBuckets();
 269             }
 270
 271         } else {
 272
 273             // get offset for adjustment
 274             int offset = getOffset(timestamp);
 275
 276             // Compact as needed
 277             while(fLastBucket + offset >= fNbBuckets) {
 278                 mergeBuckets();
 279                 offset = getOffset(timestamp);
 280             }
 281
 282             moveBuckets(offset);
 283
 284             fLastBucket = fLastBucket + offset;
 285
 286             fFirstBucketTime = fFirstBucketTime - offset*fBucketDuration;
 287             updateEndTime();
 288         }
 289
 290         // Increment the right bucket
 291         int index = (int) ((timestamp - fFirstBucketTime) / fBucketDuration);
 292         fBuckets[index]++;
 293         fNbEvents++;
 294         if (fLastBucket < index)
 295             fLastBucket = index;
 296
 297         fireModelUpdateNotification(eventCount);
 298     }
 299
 300     /**
 301      * Scale the model data to the width, height and bar width requested.
 302      *
 303      * @param width
 304      * @param height
 305      * @param bar width
 306      * @return the result array of size [width] and where the highest value
 307      *         doesn't exceed [height]
 308      */
 309     @Override
 310     public HistogramScaledData scaleTo(int width, int height, int barWidth) {
 311         // Basic validation
 312         if (width <= 0 ||  height <= 0 || barWidth <= 0)
 313             throw new AssertionError("Invalid histogram dimensions (" + width + "x" + height + ", barWidth=" + barWidth + ")"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
 314
 315         // The result structure
 316         HistogramScaledData result = new HistogramScaledData(width, height, barWidth);
 317
 318         // Scale horizontally
 319         result.fMaxValue = 0;
 320
 321         int nbBars = width / barWidth;
 322         int bucketsPerBar = fLastBucket / nbBars + 1;
 323         result.fBucketDuration = bucketsPerBar * fBucketDuration;
 324         for (int i = 0; i < nbBars; i++) {
 325             int count = 0;
 326             for (int j = i * bucketsPerBar; j < (i + 1) * bucketsPerBar; j++) {
 327                 if (fNbBuckets <= j)
 328                     break;
 329                 count += fBuckets[j];
 330             }
 331             result.fData[i] = count;
 332             result.fLastBucket = i;
 333             if (result.fMaxValue < count)
 334                 result.fMaxValue = count;
 335         }
 336
 337         // Scale vertically
 338         if (result.fMaxValue > 0) {
 339             result.fScalingFactor = (double) height / result.fMaxValue;
 340         }
 341
 342         // Set the current event index in the scaled histogram
 343         if (fCurrentEventTime >= fFirstBucketTime && fCurrentEventTime <= fLastEventTime)
 344             result.fCurrentBucket = (int) ((fCurrentEventTime - fFirstBucketTime) / fBucketDuration) / bucketsPerBar;
 345         else
 346             result.fCurrentBucket = HistogramScaledData.OUT_OF_RANGE_BUCKET;
 347
 348         result.fFirstBucketTime = fFirstBucketTime;
 349         result.fFirstEventTime = fFirstEventTime;
 350         return result;
 351     }
 352
 353     // ------------------------------------------------------------------------
 354     // Helper functions
 355     // ------------------------------------------------------------------------
 356
 357     private void updateEndTime() {
 358         fTimeLimit = fFirstBucketTime + fNbBuckets * fBucketDuration;
 359     }
 360
 361     private void mergeBuckets() {
 362         for (int i = 0; i < fNbBuckets / 2; i++) {
 363             fBuckets[i] = fBuckets[2 * i] + fBuckets[2 * i + 1];
 364         }
 365         Arrays.fill(fBuckets, fNbBuckets / 2, fNbBuckets, 0);
 366         fBucketDuration *= 2;
 367         updateEndTime();
 368         fLastBucket = fNbBuckets / 2 - 1;
 369     }
 370
 371     private void moveBuckets(int offset) {
 372         for(int i = fNbBuckets - 1; i >= offset; i--) {
 373             fBuckets[i] = fBuckets[i-offset];
 374         }
 375
 376         for (int i = 0; i < offset; i++) {
 377             fBuckets[i] = 0;
 378         }
 379     }
 380
 381     private int getOffset(long timestamp) {
 382         int offset = (int) ((fFirstBucketTime - timestamp) / fBucketDuration);
 383         if ((fFirstBucketTime - timestamp) % fBucketDuration != 0) {
 384             offset++;
 385         }
 386         return offset;
 387     }
 388
 389 }