ContentionBenchmark.java

package com.fasterxml.jackson.benchmark;

import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Threads;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.module.afterburner.AfterburnerModule;
import com.instana.DoubleUtil;

public class ContentionBenchmark {

  static final MyPojo pojo;
  static final ObjectWriter objectWriter;

  static {
    pojo = new MyPojo(Arrays.asList(new SubTypeA("1", "1"), new SubTypeB("2", "2"), new SubTypeA("3", "3")));
    objectWriter = configureObjectMapper(new ObjectMapper()).writerFor(MyPojo.class);
  }

  public static ObjectMapper configureObjectMapper(ObjectMapper mapper) {
    // These are the properties we use. I doubt they have any effect, but included for completeness
    mapper.configure(DeserializationFeature.USE_LONG_FOR_INTS, true);
    mapper.enable(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE);
    mapper.enable(MapperFeature.ACCEPT_CASE_INSENSITIVE_ENUMS);
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    mapper.getFactory().enable(JsonParser.Feature.ALLOW_MISSING_VALUES);
    mapper.getFactory().disable(JsonFactory.Feature.INTERN_FIELD_NAMES);
    mapper.getFactory().disable(JsonFactory.Feature.CANONICALIZE_FIELD_NAMES);
    SimpleModule module = new SimpleModule();
    module.addAbstractTypeMapping(Map.class, HashMap.class);
    module.addSerializer(Double.class, new DoubleSerializer());
    mapper.registerModule(module);
    mapper.registerModule(new AfterburnerModule());
    return mapper;
  }

  public static class DoubleSerializer extends JsonSerializer<Double> {
    @Override
    public void serialize(Double value, JsonGenerator jgen, SerializerProvider provider)
        throws IOException, JsonProcessingException {
      jgen.writeNumber(DoubleUtil.toString(value.doubleValue(), 4));
    }
  }

  @Benchmark
  @Threads(4)
  public byte[] benchContention() throws JsonProcessingException {
    return objectWriter.writeValueAsBytes(pojo);
  }
}

MyPojo.java

package com.fasterxml.jackson.benchmark;

import java.util.List;

public class MyPojo {

  final List<PolyType> list;

  public MyPojo(List<PolyType> list) {
    this.list = list;
  }

  public List<PolyType> getList() {
    return list;
  }
}

PolyType.java

package com.fasterxml.jackson.benchmark;

public abstract class PolyType {

  public String name;

  public PolyType(String name) {
    this.name = name;
  }

  public String getName() {
    return name;
  }
}

SubTypeA.java

package com.fasterxml.jackson.benchmark;

public class SubTypeA extends PolyType {
  private String attrib;

  public SubTypeA(String name, String attrib) {
    super(name);
    this.attrib = attrib;
  }

  public String getAttrib() {
    return attrib;
  }
}

SubTypeB.java

package com.fasterxml.jackson.benchmark;

public class SubTypeB extends PolyType {
  private String attrib;

  public SubTypeB(String name, String attrib) {
    super(name);
    this.attrib = attrib;
  }

  public String getAttrib() {
    return attrib;
  }
}