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    1   /**
    2    * Copyright (c) 2002-2011 "Neo Technology,"
    3    * Network Engine for Objects in Lund AB [http://neotechnology.com]
    4    *
    5    * This file is part of Neo4j.
    6    *
    7    * Neo4j is free software: you can redistribute it and/or modify
    8    * it under the terms of the GNU General Public License as published by
    9    * the Free Software Foundation, either version 3 of the License, or
    10   * (at your option) any later version.
    11   *
    12   * This program is distributed in the hope that it will be useful,
    13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    15   * GNU General Public License for more details.
    16   *
    17   * You should have received a copy of the GNU General Public License
    18   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    19   */
    20  package org.neo4j.server.rrd;
    21
    22  import org.rrd4j.core.Sample;
    23
    24  import javax.management.MalformedObjectNameException;
    25  import java.io.IOException;
    26  import java.util.Date;
    27
    28  /**
    29   * Manages sampling the state of the database and storing the samples in a round
    30   * robin database instance.
    31   */
    32  public class RrdSampler {
    33      /**
    34       * The current sampling object. This is created when calling #start().
    35       */
    36      private Sample sample;
    37      private Sampleable[] samplables;
    38
    39      /**
    40       * Keep track of whether to run the update task or not.
    41       */
    42      protected RrdSampler(Sample sample, Sampleable... samplables) throws MalformedObjectNameException {
    43          this.sample = sample;
    44          this.samplables = samplables;
    45      }
    46
    47      /*
    48       * This method is called each time we want a snapshot of the current system
    49       * state. Data sources to work with are defined in {@link
    50       * RrdManager#getRrdDB()}
    51       */
    52      public Sample updateSample() {
    53          try {
    54              sample.setTime(new Date().getTime());
    55              for (Sampleable samplable : samplables) {
    56                  sample.setValue(samplable.getName(), samplable.getValue());
    57              }
    58
    59              sample.update();
    60              return sample;
    61          } catch (IOException e) {
    62              throw new RuntimeException("IO Error trying to access round robin database path. See nested exception.", e);
    63          }
    64      }
    65  }