FetchSource


1   /* ============================================================
2    * JRobin : Pure java implementation of RRDTool's functionality
3    * ============================================================
4    *
5    * Project Info:  http://www.jrobin.org
6    * Project Lead:  Sasa Markovic (saxon@jrobin.org)
7    * 
8    * Developers:    Sasa Markovic (saxon@jrobin.org)
9    *                Arne Vandamme (cobralord@jrobin.org)
10   *
11   * (C) Copyright 2003, by Sasa Markovic.
12   *
13   * This library is free software; you can redistribute it and/or modify it under the terms
14   * of the GNU Lesser General Public License as published by the Free Software Foundation;
15   * either version 2.1 of the License, or (at your option) any later version.
16   *
17   * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
18   * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19   * See the GNU Lesser General Public License for more details.
20   *
21   * You should have received a copy of the GNU Lesser General Public License along with this
22   * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
23   * Boston, MA 02111-1307, USA.
24   */
25  package org.jrobin.graph;
26  
27  import java.util.ArrayList  ;
28  import java.io.IOException  ;
29  
30  import org.jrobin.core.*;
31  
32  /**
33   * <p>Class used to group datasources per RRD db, for faster fetching.
34   * A FetchSource represents one RRD database file, and will take care of all datasource
35   * fetching using objects of the <code>core</code> package.  Fetching will be done in such 
36   * a way that all datasources per consolidation function are fetched with the minimum possible
37   * file reads.</p>
38   * 
39   * @author Arne Vandamme (cobralord@jrobin.org)
40   */
41  class FetchSource 
42  {
43      // ================================================================
44      // -- Members
45      // ================================================================
46      protected static final int AVG          = 0;
47      protected static final int MAX          = 1;
48      protected static final int MIN          = 2;
49      protected static final int LAST         = 3;
50      protected static final int MAX_CF       = 4;
51      
52      protected static final String  [] cfNames = new String  [] { "AVERAGE", "MAX", "MIN", "LAST" };
53  
54      private RrdDb rrd;
55      private RrdDef rrdDef;
56  
57      private String   rrdFile;                     // Holds the name of the RRD file
58      private String   backendName;
59  
60      private int numSources                  = 0;
61      private ArrayList  [] datasources         = new ArrayList  [MAX_CF];
62  
63      private FetchSourceList listReference   = null;
64  
65  
66      // ================================================================
67      // -- Constructors
68      // ================================================================
69      /**
70       * Constructs a FetchSource object based on a RRD file name.
71       *
72       * @param rrdFile Name of the RRD file holding all datasources.
73       * @param listRef Reference to the FetchSourceList this FetchSource belongs to.
74       */
75      protected FetchSource( String   rrdFile, FetchSourceList listRef )
76      {
77          this.rrdFile    = rrdFile;
78          listReference   = listRef;
79  
80          // Initialization of datasource lists per CF
81          for (int i = 0; i < datasources.length; i++)
82              datasources[i] = new ArrayList  ( 10 );
83      }
84      
85      /**
86       * Constructs a FetchSource object based on a RRD file name, and
87       * adds a given datasource to the datasources list.
88       *
89       * @param rrdFile Name of the RRD file holding all datasources.
90       * @param consolFunc Consolidation function of the datasource to fetch.
91       * @param dsName Internal name of the datasource in the RRD file.
92       * @param name Variable name of the datasource in the graph definition.
93       * @param listRef Reference to the FetchSourceList this FetchSource belongs to.
94       * @throws RrdException Thrown in case of a JRobin specific error.
95       */
96      protected FetchSource( String   rrdFile, String   consolFunc, String   dsName, String   name, FetchSourceList listRef ) throws RrdException
97      {
98          this( rrdFile, listRef );
99          addSource( consolFunc, dsName, name );
100     }
101 
102     /**
103      * Constructs a FetchSource object based on a RRD file name, and
104      * adds a given datasource to the datasources list.
105      *
106      * @param rrdFile Name of the RRD file holding all datasources.
107      * @param consolFunc Consolidation function of the datasource to fetch.
108      * @param dsName Internal name of the datasource in the RRD file.
109      * @param name Variable name of the datasource in the graph definition.
110      * @param backendName Name of the RrdBackendFactory to use for this RrdDb.
111      * @param listRef Reference to the FetchSourceList this FetchSource belongs to.
112      * @throws RrdException Thrown in case of a JRobin specific error.
113      */
114     protected FetchSource( String   rrdFile, String   consolFunc, String   dsName, String   name, String   backendName, FetchSourceList listRef ) throws RrdException
115     {
116         this( rrdFile, consolFunc, dsName, name, listRef );
117         setBackendFactory( backendName );
118     }
119 
120     // ================================================================
121     // -- Protected methods
122     // ================================================================
123     /**
124      * Adds a given datasource to the datasources list for this FetchSource.
125      *
126      * @param consolFunc Consolidation function of the datasource to fetch.
127      * @param dsName Internal name of the datasource in the RRD file.
128      * @param name Variable name of the datasource in the graph definition.
129      * @throws RrdException Thrown in case of a JRobin specific error.
130      */
131     protected void addSource( String   consolFunc, String   dsName, String   name ) throws RrdException
132     {
133         if ( consolFunc.equalsIgnoreCase("AVERAGE") || consolFunc.equalsIgnoreCase("AVG") )
134             datasources[AVG].add( new String  [] { dsName, name } );
135         else if ( consolFunc.equalsIgnoreCase("MAX") || consolFunc.equalsIgnoreCase("MAXIMUM") )
136             datasources[MAX].add( new String  [] { dsName, name } );
137         else if ( consolFunc.equalsIgnoreCase("MIN") || consolFunc.equalsIgnoreCase("MINIMUM") )
138             datasources[MIN].add( new String  [] { dsName, name } );
139         else if ( consolFunc.equalsIgnoreCase("LAST") )
140             datasources[LAST].add( new String  [] { dsName, name } );
141         else
142             throw new RrdException( "Invalid consolidation function specified." );
143         
144         numSources++;               
145     }
146 
147     /**
148      * Sets the name of the RrdBackendFactory that should be used for this FetchSource.
149      * The factory should be registered with RrdBackendFactory static.
150      *
151      * @param backendName Name of the RrdBackendFactory to use for this RrdDb.
152      */
153     protected void setBackendFactory( String   backendName ) {
154         this.backendName = backendName;
155     }
156 
157     /**
158      * Fetches all datavalues for a given timespan out of the provided RRD file.
159      *
160      * @param startTime Start time of the given timespan.
161      * @param endTime End time of the given timespan.
162      * @param resolution Resolution for the fetch request.
163      * @return A <code>ValueExtractor</code> object holding all fetched data.
164      * @throws IOException Thrown in case of fetching I/O error.
165      * @throws RrdException Thrown in case of a JRobin specific error.
166      */
167     protected ValueExtractor fetch ( long startTime, long endTime, long resolution, int reduceFactor ) throws IOException  , RrdException
168     {
169         if ( rrd == null )
170             openRrd();
171 
172         int dsSize              = 0;
173         String  [] dsNames, vNames;
174 
175         long rrdStep            = rrdDef.getStep();
176         FetchData[] result      = new FetchData[datasources.length];
177         
178         String  [] names          = new String  [numSources];
179         int tblPos      = 0;
180         
181         for (int i = 0; i < datasources.length; i++)
182         {
183             dsSize              = datasources[i].size();
184 
185             if ( dsSize > 0 )
186             {
187                 // Set the list of ds names
188                 dsNames     = new String  [ dsSize ];
189                 vNames      = new String  [ dsSize ];
190                 
191                 for (int j = 0; j < dsSize; j++ ) {
192                     String  [] spair  = (String  []) datasources[i].get(j);
193                     dsNames[j]      = spair[0];
194                     vNames[j]       = spair[1];
195                 }
196                 
197                 // Fetch datasources
198                 FetchRequest request        = rrd.createFetchRequest( cfNames[i], startTime, endTime, resolution );
199                 request.setFilter( dsNames );
200 
201                 FetchData data              = request.fetchData();
202 
203                 for (int j = 0; j < dsSize; j++)
204                     names[ data.getDsIndex(dsNames[j]) + tblPos ] = vNames[j];
205                 tblPos                      += dsSize; 
206                 
207                 result[i]                   = data;
208             }
209         }
210         
211         return new ValueExtractor( names, result, reduceFactor );
212     }
213 
214     /**
215      * Retrieves the RrdDb connected to this FetchSource.
216      * The RrdDb instance is retrieved through the use of the
217      * RrdOpener that is referred internally in the FetchSourceList.
218      * It is okay to call this method multiple times in a row.
219      *
220      * @throws IOException Thrown in case of fetching I/O error.
221      * @throws RrdException Thrown in case of a JRobin specific error.
222      */
223     protected void openRrd() throws RrdException, IOException  
224     {
225         if ( rrd == null )
226         {
227             org.jrobin.core.RrdOpener opener = listReference.getRrdOpener();
228 
229             if ( opener == null )
230                 throw new RrdException( "No RrdOpener specified for RRD management." );
231 
232             // Only open if not open yet
233             if ( rrd == null )
234                 rrd = opener.getRrd( rrdFile, getRrdBackendFactory() );
235 
236             rrdDef  = rrd.getRrdDef();
237         }
238     }
239 
240     /**
241      * Gets the RrdDb instance for this FetchSource.  If the
242      * RrdDb has not been retrieved yet, it is before this
243      * method returns. It is okay to call this method multiple
244      * times in a row.
245      *
246      * @return Reference to the RrdDb instance.
247      * @throws IOException Thrown in case of fetching I/O error.
248      * @throws RrdException Thrown in case of a JRobin specific error.
249      */
250     protected RrdDb getRrd() throws RrdException, IOException  
251     {
252         if ( rrd == null )
253             openRrd();
254 
255         return rrd;
256     }
257 
258     /**
259      * Releases the internal RrdDb reference for this FetchSource.
260      * It is okay to call this method multiple times in a row.
261      *
262      * @throws IOException Thrown in case of fetching I/O error.
263      * @throws RrdException Thrown in case of a JRobin specific error.
264      */
265     protected void release() throws RrdException, IOException  
266     {
267         if ( rrd != null )
268         {
269             org.jrobin.core.RrdOpener opener = listReference.getRrdOpener();
270 
271             if ( opener == null )
272                 throw new RrdException( "No RrdOpener specified for RRD management." );
273 
274             opener.releaseRrd( rrd );
275             rrd = null;
276         }
277     }
278 
279     /**
280      * Returns the timestamp of the last completed sample before or on the given time.
281      * This method is useful to find out the actual last timestamp for graphing, if the
282      * current time is after the last update time.  This sample can contain bad (Unknown)
283      * values, as long as the interval for it has been completed. This is not the
284      * timestamp of the last non-unknown sample!
285      *
286      * @param startTime Timestamp for which the last sample time should be calculated.
287      * @param endTime Timestamp for which the last sample time should be calculated.
288      * @param resolution Last timestamp for this particular fetch resolution.
289      * @return Last sample timestamp in seconds.
290      * @throws IOException Thrown in case of fetching I/O error.
291      * @throws RrdException Thrown in case of a JRobin specific error.
292      */
293     protected long getLastSampleTime( long startTime, long endTime, long resolution ) throws RrdException, IOException  
294     {
295         if ( rrd == null )
296             openRrd();
297 
298         long minSampleTime = Long.MAX_VALUE, sampleTime = 0;
299 
300         for ( int i = 0; i < datasources.length; i++ )
301         {
302             if ( datasources[i].size() > 0 )
303             {
304                 sampleTime = rrd.findStartMatchArchive( cfNames[i], startTime, resolution ).getEndTime();
305 
306                 if ( sampleTime < minSampleTime )
307                     minSampleTime = sampleTime;
308             }
309         }
310 
311         return minSampleTime;
312     }
313 
314     /**
315      * Returns an array of the smallest and the largest step in the set.
316      *
317      * @param startTime
318      * @param endTime
319      * @param resolution
320      * @return
321      * @throws RrdException
322      * @throws IOException
323      */
324     protected long[] getFetchStep( long startTime, long endTime, long resolution ) throws RrdException, IOException  
325     {
326         if ( rrd == null )
327             openRrd();
328 
329         long maxStep = Long.MIN_VALUE, minStep = Long.MAX_VALUE, step = 0;
330 
331         for ( int i = 0; i < datasources.length; i++ )
332         {
333             if ( datasources[i].size() > 0 )
334             {
335                 FetchRequest request    = rrd.createFetchRequest( cfNames[i], startTime, endTime, resolution );
336                 step                    = rrd.findMatchingArchive( request ).getArcStep();
337 
338                 if ( step < minStep )
339                     minStep = step;
340                 if ( step > maxStep )
341                     maxStep = step;
342             }
343         }
344 
345         return new long[] { minStep, maxStep };
346     }
347 
348     protected String   getRrdFile() {
349         return rrdFile;
350     }
351 
352     protected RrdBackendFactory getRrdBackendFactory() throws RrdException
353     {
354         if ( backendName != null )
355             return RrdBackendFactory.getFactory( backendName );
356 
357         return RrdBackendFactory.getDefaultFactory();
358     }
359 
360     public void exportXml(XmlWriter xml) {
361         for ( int i = 0; i < datasources.length; i++ ) {
362             for ( int j = 0; j < datasources[i].size(); j++ ) {
363                 String  [] pair = (String  []) datasources[i].get(j);
364                 xml.startTag("def");
365                 xml.writeTag("name", pair[1]);
366                 xml.writeTag("rrd", rrdFile);
367                 xml.writeTag("source", pair[0]);
368                 xml.writeTag("cf", cfNames[i]);
369                 xml.closeTag(); // def
370             }
371         }
372     }
373 }
374
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