class RadosClient extends DB {

  private Rados rados;
  private IoCTX ioctx;

  public static final String CONFIG_FILE_PROPERTY = "rados.configfile";
  public static final String CONFIG_FILE_DEFAULT = "/etc/ceph/ceph.conf";
  public static final String ID_PROPERTY = "rados.id";
  public static final String ID_DEFAULT = "admin";
  public static final String POOL_PROPERTY = "rados.pool";
  public static final String POOL_DEFAULT = "data";

  private boolean isInited = false;

  public void init() throws DBException {
    Properties props = getProperties();

    String configfile = props.getProperty(CONFIG_FILE_PROPERTY);
    if (configfile == null) {
      configfile = CONFIG_FILE_DEFAULT;
    }

    String id = props.getProperty(ID_PROPERTY);
    if (id == null) {
      id = ID_DEFAULT;
    }

    String pool = props.getProperty(POOL_PROPERTY);
    if (pool == null) {
      pool = POOL_DEFAULT;
    }

    // try {
    // } catch (UnsatisfiedLinkError e) {
    //   throw new DBException("RADOS library is not loaded.");
    // }

    rados = new Rados(id);
    try {
      rados.confReadFile(new File(configfile));
      rados.connect();
      ioctx = rados.ioCtxCreate(pool);
    } catch (RadosException e) {
      throw new DBException(e.getMessage() + ": " + e.getReturnValue());
    }

    isInited = true;
  }

  public void cleanup() throws DBException {
    if (isInited) {
      rados.shutDown();
      rados.ioCtxDestroy(ioctx);
      isInited = false;
    }
  }

  @Override
  public Status read(String table, String key, Set<String> fields, Map<String, ByteIterator> result) {<FILL_FUNCTION_BODY>}

  @Override
  public Status insert(String table, String key, Map<String, ByteIterator> values) {
    JSONObject json = new JSONObject();
    for (final Entry<String, ByteIterator> e : values.entrySet()) {
      json.put(e.getKey(), e.getValue().toString());
    }

    try {
      ioctx.write(key, json.toString());
    } catch (RadosException e) {
      return new Status("ERROR-" + e.getReturnValue(), e.getMessage());
    }
    return Status.OK;
  }

  @Override
  public Status delete(String table, String key) {
    try {
      ioctx.remove(key);
    } catch (RadosException e) {
      return new Status("ERROR-" + e.getReturnValue(), e.getMessage());
    }
    return Status.OK;
  }

  @Override
  public Status update(String table, String key, Map<String, ByteIterator> values) {
    Status rtn = delete(table, key);
    if (rtn.equals(Status.OK)) {
      return insert(table, key, values);
    }
    return rtn;
  }

  @Override
  public Status scan(String table, String startkey, int recordcount, Set<String> fields,
      Vector<HashMap<String, ByteIterator>> result) {
    return Status.NOT_IMPLEMENTED;
  }
}

    byte[] buffer;

    try {
      RadosObjectInfo info = ioctx.stat(key);
      buffer = new byte[(int)info.getSize()];

      ReadOp rop = ioctx.readOpCreate();
      ReadResult readResult = rop.queueRead(0, info.getSize());
      // TODO: more size than byte length possible;
      // rop.operate(key, Rados.OPERATION_NOFLAG); // for rados-java 0.3.0
      rop.operate(key, 0);
      // readResult.raiseExceptionOnError("Error ReadOP(%d)", readResult.getRVal()); // for rados-java 0.3.0
      if (readResult.getRVal() < 0) {
        throw new RadosException("Error ReadOP", readResult.getRVal());
      }
      if (info.getSize() != readResult.getBytesRead()) {
        return new Status("ERROR", "Error the object size read");
      }
      readResult.getBuffer().get(buffer);
    } catch (RadosException e) {
      return new Status("ERROR-" + e.getReturnValue(), e.getMessage());
    }

    JSONObject json = new JSONObject(new String(buffer, java.nio.charset.StandardCharsets.UTF_8));
    Set<String> fieldsToReturn = (fields == null ? json.keySet() : fields);

    for (String name : fieldsToReturn) {
      result.put(name, new StringByteIterator(json.getString(name)));
    }

    return result.isEmpty() ? Status.ERROR : Status.OK;
  
<methods>public non-sealed void <init>() ,public void cleanup() throws site.ycsb.DBException,public abstract site.ycsb.Status delete(java.lang.String, java.lang.String) ,public java.util.Properties getProperties() ,public void init() throws site.ycsb.DBException,public abstract site.ycsb.Status insert(java.lang.String, java.lang.String, Map<java.lang.String,site.ycsb.ByteIterator>) ,public abstract site.ycsb.Status read(java.lang.String, java.lang.String, Set<java.lang.String>, Map<java.lang.String,site.ycsb.ByteIterator>) ,public abstract site.ycsb.Status scan(java.lang.String, java.lang.String, int, Set<java.lang.String>, Vector<HashMap<java.lang.String,site.ycsb.ByteIterator>>) ,public void setProperties(java.util.Properties) ,public abstract site.ycsb.Status update(java.lang.String, java.lang.String, Map<java.lang.String,site.ycsb.ByteIterator>) <variables>private java.util.Properties properties