FetchSourceList


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.HashMap  ;
28  import java.util.ArrayList  ;
29  import java.io.IOException  ;
30  
31  import org.jrobin.core.RrdException;
32  import org.jrobin.core.RrdDb;
33  import org.jrobin.core.RrdOpener;
34  
35  /**
36   * <p>A FetchSourceList represents a number of RRD datasources,
37   * to be used with RrdGraphDef for Graph generation.</p>
38   *
39   * @author Arne Vandamme (cobralord@jrobin.org)
40   */
41  public class FetchSourceList
42  {
43      // ================================================================
44      // -- Members
45      // ================================================================
46      private HashMap   map;
47      private ArrayList   list;
48  
49      private int defCount;
50  
51      private boolean persistent;
52      private boolean openerLocked;
53      private boolean opened;
54  
55      private RrdOpener rrdOpener;
56  
57  
58      // ================================================================
59      // -- Constructors
60      // ================================================================
61      /**
62       * Creates a new FetchSourceList with the specified default size.
63       * The size of the actual list is not limited to this number, and
64       * the list will expand automatically if necessary.  The default size
65       * should be a ballpark figure for the number of different RrdDb
66       * that will be used (usually a RrdDb corresponds with a single RRD file).
67       *
68       * @param defaultSize Default size of the FetchSourceList.
69       */
70      public FetchSourceList( int defaultSize )
71      {
72          this( defaultSize, false, false );
73      }
74  
75      /**
76       * Creates a new FetchSourceList with the specified default size.
77       * The size of the actual list is not limited to this number, and
78       * the list will expand automatically if necessary.  The default size
79       * should be a ballpark figure for the number of different RrdDb
80       * that will be used (usually a RrdDb corresponds with a single RRD file).
81       *
82       * @param defaultSize Default size of the FetchSourceList.
83       * @param persistent True if the list is persistent, false if not.
84       */
85      public FetchSourceList( int defaultSize, boolean persistent, boolean lockOpener )
86      {
87          map                 = new HashMap  ( defaultSize );
88          list                = new ArrayList  ( defaultSize );
89  
90          opened              = false;
91          this.persistent     = persistent;
92          this.openerLocked   = lockOpener;
93      }
94  
95      /**
96       * Creates a new FetchSourceList with the specified default size.
97       * The size of the actual list is not limited to this number, and
98       * the list will expand automatically if necessary.  The default size
99       * should be a ballpark figure for the number of different RrdDb
100      * that will be used (usually a RrdDb corresponds with a single RRD file).
101      *
102      * @param defaultSize Default size of the FetchSourceList.
103      * @param persistent True if the list is persistent, false if not.
104      * @param rrdOpener Reference to the RrdOpener object that will be used
105      *                  for RrdDb retrieval.
106      */
107     public FetchSourceList( int defaultSize, boolean persistent, boolean lockOpener, RrdOpener rrdOpener )
108     {
109         this( defaultSize, persistent , lockOpener);
110 
111         this.rrdOpener  = rrdOpener;
112     }
113 
114 
115     // ================================================================
116     // -- Public methods
117     // ================================================================
118     /**
119      * Sets the internal RrdOpener object to use for RrdDb retrieval.
120      *
121      * @param rrdOpener Reference to the corresponding RrdOpener instance.
122      */
123     public void setRrdOpener( RrdOpener rrdOpener )
124     {
125         // Only allow RrdOpener change if not persistent
126         if ( !persistent && !openerLocked )
127             this.rrdOpener  = rrdOpener;
128     }
129 
130     public RrdOpener getRrdOpener() {
131         return rrdOpener;
132     }
133 
134     /**
135      * Sets the persistency state of the FetchSourceList.
136      * If the list is set as persistent, RrdDb's can be opened
137      * and retrieved, but not released, and the RrdOpener reference
138      * can not be changed.  This is useful to avoid premature closing
139      * and reopening of datasources for performance reasons.
140      *
141      * Setting a FetchSourceList as persistent requires you to manually
142      * control releasing all datasources (all calls to openAll() will
143      * still succeed).
144      *
145      * @param persistent True if the list should behave as persistent.
146      */
147     public void setPersistent( boolean persistent )
148     {
149         this.persistent = persistent;
150     }
151 
152     /**
153      * This locks the RrdOpener in the FetchSourceList.  Subsequent call so
154      * setRrdOpener() will be ignored until it is unlocked.
155      */
156     public void lockOpener() {
157         openerLocked = true;
158     }
159 
160     /**
161      * Unlocks the RrdOpener object, means calls to setRrdOpener() can change
162      * the internal rrdOpener object.
163      */
164     public void unlockOpener() {
165         openerLocked = false;
166     }
167 
168     /**
169      * Returns the number of FetchSources hold in the list.
170      * @return Number of different FetchSources.
171      */
172     public int size() {
173         return list.size();
174     }
175 
176     /**
177      * Returns the number of Defs represented by the
178      * different FetchSources.
179      * @return Number of Def definitions.
180      */
181     public  int defCount() {
182         return defCount;
183     }
184 
185     /**
186      * Retrieves (opens) all RrdDb instances related to the
187      * different FetchSources.
188      * It is safe to call this method multiple times in a row.
189      *
190      * @throws IOException Thrown in case of fetching I/O error.
191      * @throws RrdException Thrown in case of a JRobin specific error.
192      */
193     public void openAll() throws RrdException, IOException  
194     {
195         if ( opened ) return;
196 
197         for ( int i = 0; i < size(); i++ )
198             get(i).openRrd();
199 
200         opened = true;
201     }
202 
203     /**
204      * Releases all RrdDb instances for the FetchSources.
205      * It is safe to call this method multiple times in a row.
206      * In case of a persistent list, this method does nothing
207      * until persistency is removed.
208      *
209      * @throws IOException Thrown in case of fetching I/O error.
210      * @throws RrdException Thrown in case of a JRobin specific error.
211      */
212     public void releaseAll() throws RrdException, IOException  
213     {
214         if ( persistent ) return;       // Do not allow release if this FSList is persistent
215 
216         for ( int i = 0; i < size(); i++ )
217             get(i).release();
218 
219         opened = false;
220     }
221 
222     /**
223      * Clears up the FetchSourceList for new use.
224      * This removes persistency, releases all RrdDb instances, and
225      * clears the internal list of FetchSources.  After clear()
226      * the list is empty.
227      *
228      * @throws IOException Thrown in case of fetching I/O error.
229      * @throws RrdException Thrown in case of a JRobin specific error.
230      */
231     public void clear() throws RrdException, IOException  
232     {
233         persistent   = false;
234 
235         releaseAll();
236 
237         map.clear();
238         list.clear();
239     }
240 
241     /**
242      * Returns the highest last update time in seconds of the datasources
243      * represented by the list.  If the update time differs for different
244      * datasources, the highest overall timestamp will be returned.
245      * 
246      * @return Last update time in seconds.
247      * @throws IOException Thrown in case of fetching I/O error.
248      * @throws RrdException Thrown in case of a JRobin specific error.
249      */
250     public long getLastUpdateTime() throws RrdException, IOException  
251     {
252         RrdDb rrd;
253 
254         long maxUpdateTime  = 0;
255         long lastUpdateTime = 0;
256 
257         for ( int i = 0; i < size(); i++ )
258         {
259             rrd = get(i).getRrd();
260 
261             lastUpdateTime  = rrd.getLastUpdateTime();
262             if ( lastUpdateTime > maxUpdateTime )
263                 maxUpdateTime   = lastUpdateTime;
264         }
265 
266         return maxUpdateTime;
267     }
268 
269     /**
270      * Adds a datasource for graphing purposes to the list, see
271      * {@link RrdGraphDef#datasource( java.lang.String, java.lang.String,
272      * java.lang.String, java.lang.String, java.lang.String )}.
273 
274      * @param name Internal datasource name, to be used in GraphDefs.
275      * @param file Path to RRD file.
276      * @param dsName Data source name defined in the RRD file.
277      * @param consolFunc Consolidation function that will be used to extract data from the RRD
278      * file ("AVERAGE", "MIN", "MAX" or "LAST").
279      * @param backend Name of the RrdBackendFactory that should be used for this RrdDb.
280      * @throws RrdException Thrown in case of a JRobin specific error.
281      */
282     public void add( String   name, String   file, String   dsName, String   consolFunc, String   backend ) throws RrdException
283     {
284         if ( map.containsKey(file) )
285         {
286             FetchSource rf = (FetchSource) map.get(file);
287             rf.addSource( consolFunc, dsName, name );
288         }
289         else
290         {
291             FetchSource fs = new FetchSource( file, consolFunc, dsName, name, backend, this );
292             map.put( file, fs );
293             list.add( fs );
294         }
295 
296         defCount++;
297     }
298 
299     /**
300      * Adds a datasource for graphing purposes to the list, see 
301      * {@link RrdGraphDef#datasource( java.lang.String, java.lang.String,
302      * java.lang.String, java.lang.String )}.
303      *
304      * @param name Internal datasource name, to be used in GraphDefs.
305      * @param file Path to RRD file.
306      * @param dsName Data source name defined in the RRD file.
307      * @param consolFunc Consolidation function that will be used to extract data from the RRD
308      * file ("AVERAGE", "MIN", "MAX" or "LAST").
309      * @throws RrdException Thrown in case of a JRobin specific error.
310      */
311     public void add( String   name, String   file, String   dsName, String   consolFunc ) throws RrdException
312     {
313         if ( map.containsKey(file) )
314         {
315             FetchSource rf = (FetchSource) map.get(file);
316             rf.addSource( consolFunc, dsName, name );
317         }
318         else
319         {
320             FetchSource fs = new FetchSource( file, consolFunc, dsName, name, this );
321             map.put( file, fs );
322             list.add( fs );
323         }
324 
325         defCount++;
326     }
327 
328     // ================================================================
329     // -- Protected (package) methods
330     // ================================================================
331     /**
332      * Returns the FetchSource for the given index.
333      * 
334      * @param index Index of the FetchSource in the list.
335      * @return FetchSource instance.
336      */
337     protected FetchSource get( int index )
338     {
339         return (FetchSource) list.get(index);
340     }
341 }
342
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