statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/statesystem/core/ITmfStateSystem.java

   1 /*******************************************************************************
   2  * Copyright (c) 2012, 2016 Ericsson and others.
   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  *   Alexandre Montplaisir - Initial API
  11  ******************************************************************************/
  12
  13 package org.eclipse.tracecompass.statesystem.core;
  14
  15 import java.util.List;
  16
  17 import org.eclipse.jdt.annotation.NonNull;
  18 import org.eclipse.tracecompass.statesystem.core.exceptions.AttributeNotFoundException;
  19 import org.eclipse.tracecompass.statesystem.core.exceptions.StateSystemDisposedException;
  20 import org.eclipse.tracecompass.statesystem.core.exceptions.TimeRangeException;
  21 import org.eclipse.tracecompass.statesystem.core.interval.ITmfStateInterval;
  22 import org.eclipse.tracecompass.statesystem.core.statevalue.ITmfStateValue;
  23
  24
  25 /**
  26  * This is the read-only interface to the generic state system. It contains all
  27  * the read-only quark-getting methods, as well as the history-querying ones.
  28  *
  29  * @author Alexandre Montplaisir
  30  * @noimplement Only the internal StateSystem class should implement this
  31  *              interface.
  32  */
  33 public interface ITmfStateSystem {
  34
  35     /** Root attribute quark
  36      * @since 2.0*/
  37     int ROOT_ATTRIBUTE = -1;
  38     /** Invalid attribute quark
  39      * @since 2.0*/
  40     int INVALID_ATTRIBUTE = -2;
  41
  42     /**
  43      * Get the ID of this state system.
  44      *
  45      * @return The state system's ID
  46      */
  47     String getSSID();
  48
  49     /**
  50      * Return the start time of this history. It usually matches the start time
  51      * of the original trace.
  52      *
  53      * @return The history's registered start time
  54      */
  55     long getStartTime();
  56
  57     /**
  58      * Return the current end time of the history.
  59      *
  60      * @return The current end time of this state history
  61      */
  62     long getCurrentEndTime();
  63
  64     /**
  65      * Check if the construction of this state system was cancelled or not. If
  66      * false is returned, it can mean that the building was finished
  67      * successfully, or that it is still ongoing. You can check independently
  68      * with {@link #waitUntilBuilt()} if it is finished or not.
  69      *
  70      * @return If the construction was cancelled or not. In true is returned, no
  71      *         queries should be run afterwards.
  72      */
  73     boolean isCancelled();
  74
  75     /**
  76      * While it's possible to query a state history that is being built,
  77      * sometimes we might want to wait until the construction is finished before
  78      * we start doing queries.
  79      *
  80      * This method blocks the calling thread until the history back-end is done
  81      * building. If it's already built (ie, opening a pre-existing file) this
  82      * should return immediately.
  83      *
  84      * You should always check with {@link #isCancelled()} if it is safe to
  85      * query this state system before doing queries.
  86      */
  87     void waitUntilBuilt();
  88
  89     /**
  90      * Wait until the state system construction is finished. Similar to
  91      * {@link #waitUntilBuilt()}, but we also specify a timeout. If the timeout
  92      * elapses before the construction is finished, the method will return.
  93      *
  94      * The return value determines if the return was due to the construction
  95      * finishing (true), or the timeout elapsing (false).
  96      *
  97      * This can be useful, for example, for a component doing queries
  98      * periodically to the system while it is being built.
  99      *
 100      * @param timeout
 101      *            Timeout value in milliseconds
 102      * @return True if the return was due to the construction finishing, false
 103      *         if it was because the timeout elapsed. Same logic as
 104      *         {@link java.util.concurrent.CountDownLatch#await(long, java.util.concurrent.TimeUnit)}
 105      */
 106     boolean waitUntilBuilt(long timeout);
 107
 108     /**
 109      * Notify the state system that the trace is being closed, so it should
 110      * clean up, close its files, etc.
 111      */
 112     void dispose();
 113
 114     // ------------------------------------------------------------------------
 115     // Read-only quark-getting methods
 116     // ------------------------------------------------------------------------
 117
 118     /**
 119      * Return the current total amount of attributes in the system. This is also
 120      * equal to the quark that will be assigned to the next attribute that's
 121      * created.
 122      *
 123      * @return The current number of attributes in the system
 124      */
 125     int getNbAttributes();
 126
 127     /**
 128      * Basic quark-retrieving method. Pass an attribute in parameter as an array
 129      * of strings, the matching quark will be returned.
 130      * <p>
 131      * This version will NOT create any new attributes. If an invalid attribute
 132      * is requested, an exception will be thrown.
 133      * <p>
 134      * If it is expected that the requested attribute might be absent, it is
 135      * recommended to use {@link #optQuarkAbsolute(String...)} instead.
 136      *
 137      * @param attribute
 138      *            Attribute given as its full path in the Attribute Tree
 139      * @return The quark of the requested attribute, if it existed.
 140      * @throws AttributeNotFoundException
 141      *             This exception is thrown if the requested attribute simply
 142      *             did not exist in the system.
 143      */
 144     int getQuarkAbsolute(String... attribute)
 145             throws AttributeNotFoundException;
 146
 147     /**
 148      * Quark-retrieving method for an optional attribute that may or may not be
 149      * present. Pass an attribute in parameter as an array of strings, if it
 150      * exists, the matching quark will be returned.
 151      * <p>
 152      * This version will NOT create any new attributes. If an attribute that
 153      * does not exist is requested, {@link #INVALID_ATTRIBUTE} will be returned.
 154      *
 155      * @param attribute
 156      *            Attribute given as its full path in the Attribute Tree
 157      * @return The quark of the requested attribute, or
 158      *         {@link #INVALID_ATTRIBUTE} if it does not exist.
 159      * @since 2.0
 160      */
 161     int optQuarkAbsolute(String... attribute);
 162
 163     /**
 164      * "Relative path" quark-getting method. Instead of specifying a full path,
 165      * if you know the path is relative to another attribute for which you
 166      * already have the quark, use this for better performance.
 167      * <p>
 168      * This is useful for cases where a lot of modifications or queries will
 169      * originate from the same branch of the attribute tree : the common part of
 170      * the path won't have to be re-hashed for every access.
 171      * <p>
 172      * This version will NOT create any new attributes. If an invalid attribute
 173      * is requested, an exception will be thrown.
 174      * <p>
 175      * If it is expected that the requested sub-attribute might be absent, it is
 176      * recommended to use {@link #optQuarkRelative(int, String...)} instead.
 177      *
 178      * @param startingNodeQuark
 179      *            The quark of the attribute from which 'subPath' originates.
 180      * @param subPath
 181      *            "Rest" of the path to get to the final attribute
 182      * @return The matching quark, if it existed
 183      * @throws IndexOutOfBoundsException
 184      *             If the starting node quark is out of range
 185      * @throws AttributeNotFoundException
 186      *             If the sub-attribute does not exist
 187      */
 188     int getQuarkRelative(int startingNodeQuark, String... subPath)
 189             throws AttributeNotFoundException;
 190
 191     /**
 192      * "Relative path" quark-getting method for an optional attribute that may
 193      * or may not be present. Instead of specifying a full path, if you know the
 194      * path is relative to another attribute for which you already have the
 195      * quark, use this for better performance.
 196      * <p>
 197      * This is useful for cases where a lot of modifications or queries will
 198      * originate from the same branch of the attribute tree : the common part of
 199      * the path won't have to be re-hashed for every access.
 200      * <p>
 201      * This version will NOT create any new attributes. If a sub-attribute that
 202      * does not exist is requested, {@link #INVALID_ATTRIBUTE} will be returned.
 203      *
 204      * @param startingNodeQuark
 205      *            The quark of the attribute from which 'subPath' originates.
 206      * @param subPath
 207      *            "Rest" of the path to get to the final attribute
 208      * @return The quark of the requested sub-attribute, or
 209      *         {@link #INVALID_ATTRIBUTE} if it does not exist.
 210      * @throws IndexOutOfBoundsException
 211      *             If the starting node quark is out of range
 212      * @since 2.0
 213      */
 214     int optQuarkRelative(int startingNodeQuark, String... subPath);
 215
 216     /**
 217      * Return the sub-attributes of the target attribute, as a List of quarks.
 218      *
 219      * @param quark
 220      *            The attribute of which you want to sub-attributes. You can use
 221      *            {@link #ROOT_ATTRIBUTE} here to specify the root node.
 222      * @param recursive
 223      *            True if you want all recursive sub-attributes, false if you
 224      *            only want the first level.
 225      * @return A List of integers, matching the quarks of the sub-attributes.
 226      * @throws AttributeNotFoundException
 227      *             If the quark was not existing or invalid.
 228      */
 229     @NonNull List<@NonNull Integer> getSubAttributes(int quark, boolean recursive)
 230             throws AttributeNotFoundException;
 231
 232     /**
 233      * Return the sub-attributes of the target attribute, as a List of quarks,
 234      * similarly to {@link #getSubAttributes(int, boolean)}, but with an added
 235      * regex pattern to filter on the return attributes.
 236      *
 237      * @param quark
 238      *            The attribute of which you want to sub-attributes. You can use
 239      *            {@link #ROOT_ATTRIBUTE} here to specify the root node.
 240      * @param recursive
 241      *            True if you want all recursive sub-attributes, false if you
 242      *            only want the first level. Note that the returned value will
 243      *            be flattened.
 244      * @param pattern
 245      *            The regular expression to match the attribute base name.
 246      * @return A List of integers, matching the quarks of the sub-attributes
 247      *         that match the regex. An empty list is returned if there is no
 248      *         matching attribute.
 249      * @throws AttributeNotFoundException
 250      *             If the 'quark' was not existing or invalid.
 251      */
 252     @NonNull List<@NonNull Integer> getSubAttributes(int quark, boolean recursive, String pattern)
 253             throws AttributeNotFoundException;
 254
 255     /**
 256      * Batch quark-retrieving method. This method allows you to specify a path
 257      * pattern which includes a wildcard "*" somewhere. It will check all the
 258      * existing attributes in the attribute tree and return those who match the
 259      * pattern.
 260      *
 261      * For example, passing ("Threads", "*", "Exec_mode") will return the list
 262      * of quarks for attributes "Threads/1000/Exec_mode",
 263      * "Threads/1500/Exec_mode", and so on, depending on what exists at this
 264      * time in the attribute tree.
 265      *
 266      * If no wildcard is specified, the behavior is the same as
 267      * getQuarkAbsolute() (except it will return a List with one entry). This
 268      * method will never create new attributes.
 269      *
 270      * Only one wildcard "*" is supported at this time.
 271      *
 272      * @param pattern
 273      *            The array of strings representing the pattern to look for. It
 274      *            should ideally contain one entry that is only a "*".
 275      * @return A List of attribute quarks, representing attributes that matched
 276      *         the pattern. If no attribute matched, the list will be empty (but
 277      *         not null).
 278      */
 279     @NonNull List<@NonNull Integer> getQuarks(String... pattern);
 280
 281     /**
 282      * Return the name assigned to this quark. This returns only the "basename",
 283      * not the complete path to this attribute.
 284      *
 285      * @param attributeQuark
 286      *            The quark for which we want the name
 287      * @return The name of the quark
 288      * @throws IndexOutOfBoundsException
 289      *             If the attribute quark is out of range
 290      */
 291     @NonNull String getAttributeName(int attributeQuark);
 292
 293     /**
 294      * This returns the slash-separated path of an attribute by providing its
 295      * quark
 296      *
 297      * @param attributeQuark
 298      *            The quark of the attribute we want
 299      * @return One single string separated with '/', like a filesystem path
 300      * @throws IndexOutOfBoundsException
 301      *             If the attribute quark is out of range
 302      */
 303     @NonNull String getFullAttributePath(int attributeQuark);
 304
 305     /**
 306      * Return the full attribute path, as an array of strings representing each
 307      * element.
 308      *
 309      * @param attributeQuark
 310      *            The quark of the attribute we want.
 311      * @return The array of path elements
 312      * @throws IndexOutOfBoundsException
 313      *             If the attribute quark is out of range
 314      * @since 1.0
 315      */
 316     String @NonNull [] getFullAttributePathArray(int attributeQuark);
 317
 318     /**
 319      * Returns the parent quark of the attribute.
 320      *
 321      * @param attributeQuark
 322      *            The quark of the attribute
 323      * @return Quark of the parent attribute or {@link #ROOT_ATTRIBUTE} if root
 324      *         quark or no parent.
 325      * @throws IndexOutOfBoundsException
 326      *             If the attribute quark is out of range
 327      */
 328     int getParentAttributeQuark(int attributeQuark);
 329
 330     // ------------------------------------------------------------------------
 331     // Query methods
 332     // ------------------------------------------------------------------------
 333
 334     /**
 335      * Returns the current state value we have (in the Transient State) for the
 336      * given attribute.
 337      *
 338      * This is useful even for a StateHistorySystem, as we are guaranteed it
 339      * will only do a memory access and not go look on disk (and we don't even
 340      * have to provide a timestamp!)
 341      *
 342      * @param attributeQuark
 343      *            For which attribute we want the current state
 344      * @return The State value that's "current" for this attribute
 345      * @throws AttributeNotFoundException
 346      *             If the requested attribute is invalid
 347      */
 348     ITmfStateValue queryOngoingState(int attributeQuark)
 349             throws AttributeNotFoundException;
 350
 351     /**
 352      * Get the start time of the current ongoing state, for the specified
 353      * attribute.
 354      *
 355      * @param attribute
 356      *            Quark of the attribute
 357      * @return The current start time of the ongoing state
 358      * @throws AttributeNotFoundException
 359      *             If the attribute is invalid
 360      */
 361     long getOngoingStartTime(int attribute)
 362             throws AttributeNotFoundException;
 363
 364     /**
 365      * Load the complete state information at time 't' into the returned List.
 366      * You can then get the intervals for single attributes by using
 367      * List.get(n), where 'n' is the quark of the attribute.
 368      *
 369      * On average if you need around 10 or more queries for the same timestamps,
 370      * use this method. If you need less than 10 (for example, running many
 371      * queries for the same attributes but at different timestamps), you might
 372      * be better using the querySingleState() methods instead.
 373      *
 374      * @param t
 375      *            We will recreate the state information to what it was at time
 376      *            t.
 377      * @return The List of intervals, where the offset = the quark
 378      * @throws TimeRangeException
 379      *             If the 't' parameter is outside of the range of the state
 380      *             history.
 381      * @throws StateSystemDisposedException
 382      *             If the query is sent after the state system has been disposed
 383      */
 384     @NonNull List<@NonNull ITmfStateInterval> queryFullState(long t)
 385             throws StateSystemDisposedException;
 386
 387     /**
 388      * Singular query method. This one does not update the whole stateInfo
 389      * vector, like queryFullState() does. It only searches for one specific
 390      * entry in the state history.
 391      *
 392      * It should be used when you only want very few entries, instead of the
 393      * whole state (or many entries, but all at different timestamps). If you do
 394      * request many entries all at the same time, you should use the
 395      * conventional queryFullState() + List.get() method.
 396      *
 397      * @param t
 398      *            The timestamp at which we want the state
 399      * @param attributeQuark
 400      *            Which attribute we want to get the state of
 401      * @return The StateInterval representing the state
 402      * @throws TimeRangeException
 403      *             If 't' is invalid
 404      * @throws AttributeNotFoundException
 405      *             If the requested quark does not exist in the model
 406      * @throws StateSystemDisposedException
 407      *             If the query is sent after the state system has been disposed
 408      */
 409     @NonNull ITmfStateInterval querySingleState(long t, int attributeQuark)
 410             throws AttributeNotFoundException, StateSystemDisposedException;
 411 }