JSONMeasurementsExporter.java

/**                                                                                                                                                                                
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.                                                                                                                             
 *                                                                                                                                                                                 
 * Licensed under the Apache License, Version 2.0 (the "License"); you                                                                                                             
 * may not use this file except in compliance with the License. You                                                                                                                
 * may obtain a copy of the License at                                                                                                                                             
 *                                                                                                                                                                                 
 * http://www.apache.org/licenses/LICENSE-2.0                                                                                                                                      
 *                                                                                                                                                                                 
 * Unless required by applicable law or agreed to in writing, software                                                                                                             
 * distributed under the License is distributed on an "AS IS" BASIS,                                                                                                               
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or                                                                                                                 
 * implied. See the License for the specific language governing                                                                                                                    
 * permissions and limitations under the License. See accompanying                                                                                                                 
 * LICENSE file.                                                                                                                                                                   
 */
package com.yahoo.ycsb.measurements.exporter;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.impl.DefaultPrettyPrinter;

/**
 * Export measurements into a machine readable JSON file.
 */
public class JSONMeasurementsExporter implements MeasurementsExporter
{

  private JsonFactory factory = new JsonFactory();
  private JsonGenerator g;

  public JSONMeasurementsExporter(OutputStream os) throws IOException
  {

    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
    g = factory.createJsonGenerator(bw);
    g.setPrettyPrinter(new DefaultPrettyPrinter());
  }

  public void write(String metric, String measurement, int i) throws IOException
  {
    g.writeStartObject();
    g.writeStringField("metric", metric);
    g.writeStringField("measurement", measurement);
    g.writeNumberField("value", i);
    g.writeEndObject();
  }

  public void write(String metric, String measurement, double d) throws IOException
  {
    g.writeStartObject();
    g.writeStringField("metric", metric);
    g.writeStringField("measurement", measurement);
    g.writeNumberField("value", d);
    g.writeEndObject();
  }

  public void close() throws IOException
  {
    if (g != null)
    {
      g.close();
    }
  }

}