RrdDataSet


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.core;
26  
27  import java.io.IOException  ;
28  import java.io.OutputStream  ;
29  
30  /**
31   * <p>Interface to represent a JRobin dataset.  A dataset is nothing but a table of datasources, indexed
32   * by equidistant timestamps.  A dataset allows access to the internal datasources with aggregatoin methods.</p>
33   *
34   * @author Arne Vandamme (cobralord@jrobin.org)
35   */
36  public interface RrdDataSet
37  {
38      /**
39       * Returns the number of rows in this dataset.
40       *
41       * @return Number of rows (data samples).
42       */
43      public int getRowCount();
44  
45      /**
46       * Returns the number of columns in this dataset.
47       *
48       * @return Number of columns (datasources).
49       */
50      public int getColumnCount();
51  
52      /**
53       * Returns an array of timestamps covering the whole range specified in the
54       * dataset object.
55       *
56       * @return Array of equidistant timestamps.
57       */
58      public long[] getTimestamps();
59  
60      /**
61       * Returns all values for a single datasource, the returned values
62       * correspond to the timestamps returned with the {@link #getTimestamps() getTimestamps()} method.
63       *
64       * @param dsIndex Datasource index.
65       * @return Array of single datasource values.
66       */
67      public double[] getValues( int dsIndex );
68  
69      /**
70       * Returns all values for all datasources, the returned values
71       * correspond to the timestamps returned with the {@link #getTimestamps() getTimestamps()} method.
72       *
73       * @return Two-dimensional aray of all datasource values.
74       */
75      public double[][] getValues();
76  
77      /**
78       * Returns all values for a single datasource, the returned values
79       * correspond to the timestamps returned with the {@link #getTimestamps() getTimestamps()} method.
80       *
81       * @param dsName Datasource name.
82       * @return Array of single datasource values.
83       * @throws RrdException Thrown if no matching datasource name is found.
84       */
85      public double[] getValues( String   dsName ) throws RrdException;
86  
87      /**
88       * Returns the first timestamp in the dataset.
89       *
90       * @return The smallest timestamp.
91       */
92      public long getFirstTimestamp();
93  
94      /**
95       * Returns the last timestamp in the dataset.
96       *
97       * @return The biggest timestamp.
98       */
99      public long getLastTimestamp();
100 
101     /**
102      * Returns array of the names of all datasources in the set.
103      *
104      * @return Array of datasource names.
105      */
106     public String  [] getDsNames();
107 
108     /**
109      * Retrieve the table index number of a datasource by name.
110      * Names are case sensitive.
111      *
112      * @param dsName Name of the datasource for which to find the index.
113      * @return Index number of the datasource in the value table.
114      * @throws RrdException Thrown if the given datasource name cannot be found in the dataset.
115      */
116     public int getDsIndex( String   dsName ) throws RrdException;
117 
118     /**
119      * Returns the step of these datasources.
120      *
121      * @return Step as long.
122      */
123     public long getStep();
124 
125     /**
126      * Returns aggregated value from the dataset for a single datasource.
127      *
128      * @param dsName Datasource name
129      * @param consolFun Consolidation function to be applied to set datasource values datasource.
130      * Valid consolidation functions are MIN, MAX, LAST and AVERAGE
131      * @return MIN, MAX, LAST or AVERAGE value calculated from the dataset for the given datasource name
132      * @throws RrdException Thrown if the given datasource name cannot be found in the dataset.
133      */
134     public double getAggregate( String   dsName, String   consolFun ) throws RrdException;
135 
136     /**
137      * Dumps fetch data to output stream in XML format.
138      *
139      * @param outputStream Output stream to dump dataset to
140      * @throws RrdException Thrown in case of JRobin specific error.
141      * @throws IOException Thrown in case of I/O error
142      */
143     public void exportXml( OutputStream   outputStream ) throws RrdException, IOException  ;
144 
145     /**
146      * Dumps dataset to file in XML format.
147      *
148      * @param filepath Path to destination file
149      * @throws RrdException Thrown in case of JRobin specific error.
150      * @throws IOException Thrown in case of I/O error
151      */
152     public void exportXml( String   filepath ) throws RrdException, IOException  ;
153 
154     /**
155      * Dumps the dataset to XML.
156      *
157      * @return XML string format of the dataset.
158      * @throws RrdException Thrown in case of JRobin specific error.
159      * @throws IOException Thrown in case of an I/O related error.
160      */
161     public String   exportXml() throws RrdException, IOException  ;
162 }
163
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