Example usage for com.fasterxml.jackson.core JsonGenerator writeStartObject

List of usage examples for com.fasterxml.jackson.core JsonGenerator writeStartObject

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Introduction

In this page you can find the example usage for com.fasterxml.jackson.core JsonGenerator writeStartObject.

Prototype

public abstract void writeStartObject() throws IOException, JsonGenerationException;

Source Link

Document

Method for writing starting marker of a JSON Object value (character '{'; plus possible white space decoration if pretty-printing is enabled).

Usage

From source file:io.pdef.json.JsonJacksonFormat.java

private <T extends Message> void writeMessage(@Nonnull final T object, final JsonGenerator generator)
        throws IOException {
    // Mind polymorphic messages.
    @SuppressWarnings("unchecked")
    MessageDescriptor<T> polymorphic = (MessageDescriptor<T>) object.descriptor();

    generator.writeStartObject();
    for (FieldDescriptor<? super T, ?> field : polymorphic.getFields()) {
        writeMessageField(field, object, generator);
    }//w  w w.  j ava  2  s.  c om
    generator.writeEndObject();
}

From source file:net.solarnetwork.web.support.JSONView.java

@Override
protected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request,
        HttpServletResponse response) throws Exception {

    PropertyEditorRegistrar registrar = this.propertyEditorRegistrar;
    Enumeration<String> attrEnum = request.getAttributeNames();
    while (attrEnum.hasMoreElements()) {
        String key = attrEnum.nextElement();
        Object val = request.getAttribute(key);
        if (val instanceof PropertyEditorRegistrar) {
            registrar = (PropertyEditorRegistrar) val;
            break;
        }//w  w w . ja v  a  2 s .  co  m
    }

    response.setCharacterEncoding(UTF8_CHAR_ENCODING);
    response.setContentType(getContentType());
    Writer writer = response.getWriter();
    if (this.includeParentheses) {
        writer.write('(');
    }
    JsonGenerator json = new JsonFactory().createGenerator(writer);
    json.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false);
    if (indentAmount > 0) {
        json.useDefaultPrettyPrinter();
    }
    json.writeStartObject();
    for (String key : model.keySet()) {
        Object val = model.get(key);
        writeJsonValue(json, key, val, registrar);
    }
    json.writeEndObject();
    json.close();
    if (this.includeParentheses) {
        writer.write(')');
    }
}

From source file:org.n52.tamis.core.json.serialize.processes.execute.ExecuteOutputSerializer.java

@Override
public void serialize(ExecuteOutput output_simple, JsonGenerator jsonGenerator, SerializerProvider serProvider)
        throws IOException, JsonProcessingException {

    logger.info("Start serialization of output \"{}\"", output_simple);

    /*/*ww  w. ja  v  a  2 s . c o  m*/
     * write the input as WPS "Data" element
     * 
     * expected structure looks like:
     * 
     *    {
          "_mimeType": "text/xml",
          "_id": "complexOutput",
          "_transmission": "reference"
      }
     */

    jsonGenerator.writeStartObject();

    jsonGenerator.writeStringField("_mimeType", output_simple.getType());

    jsonGenerator.writeStringField("_id", output_simple.getId());

    jsonGenerator.writeStringField("_transmission", output_simple.getTransmission());

    jsonGenerator.writeEndObject();

    logger.info("serialization of output ended.");
}

From source file:com.neoteric.starter.metrics.report.elastic.ElasticsearchReporter.java

private void checkForIndexTemplate() {
    try {// w  w  w .  j  a  va 2 s  . c om
        HttpURLConnection connection = openConnection("/_template/metrics_template", "HEAD");
        connection.disconnect();
        boolean isTemplateMissing = connection.getResponseCode() == HttpURLConnection.HTTP_NOT_FOUND;

        // nothing there, lets create it
        if (isTemplateMissing) {
            LOGGER.debug("No metrics template found in elasticsearch. Adding...");
            HttpURLConnection putTemplateConnection = openConnection("/_template/metrics_template", "PUT");
            JsonGenerator json = new JsonFactory().createGenerator(putTemplateConnection.getOutputStream());
            json.writeStartObject();
            json.writeStringField("template", index + "*");
            json.writeObjectFieldStart("mappings");

            json.writeObjectFieldStart("_default_");
            json.writeObjectFieldStart("_all");
            json.writeBooleanField("enabled", false);
            json.writeEndObject();
            json.writeObjectFieldStart("properties");
            json.writeObjectFieldStart("name");
            json.writeObjectField("type", "string");
            json.writeObjectField("index", "not_analyzed");
            json.writeEndObject();
            json.writeEndObject();
            json.writeEndObject();

            json.writeEndObject();
            json.writeEndObject();
            json.flush();

            putTemplateConnection.disconnect();
            if (putTemplateConnection.getResponseCode() != HttpStatus.OK.value()) {
                LOGGER.error(
                        "Error adding metrics template to elasticsearch: {}/{}"
                                + putTemplateConnection.getResponseCode(),
                        putTemplateConnection.getResponseMessage());
            }
        }
        checkedForIndexTemplate = true;
    } catch (IOException e) {
        LOGGER.error("Error when checking/adding metrics template to elasticsearch", e);
    }
}

From source file:org.springframework.cloud.netflix.hystrix.amqp.HystrixStreamTask.java

@Scheduled(fixedRateString = "${hystrix.stream.amqp.gatherRate:500}")
public void gatherMetrics() {
    try {/*from w  ww.ja v a 2s.  c  o  m*/
        // command metrics
        Collection<HystrixCommandMetrics> instances = HystrixCommandMetrics.getInstances();
        if (!instances.isEmpty()) {
            log.trace("gathering metrics size: " + instances.size());
        }

        ServiceInstance localService = this.discoveryClient.getLocalServiceInstance();

        for (HystrixCommandMetrics commandMetrics : instances) {
            HystrixCommandKey key = commandMetrics.getCommandKey();
            HystrixCircuitBreaker circuitBreaker = HystrixCircuitBreaker.Factory.getInstance(key);

            StringWriter jsonString = new StringWriter();
            JsonGenerator json = this.jsonFactory.createGenerator(jsonString);

            json.writeStartObject();

            addServiceData(json, localService);
            json.writeObjectFieldStart("data");
            json.writeStringField("type", "HystrixCommand");
            String name = key.name();

            if (this.properties.isPrefixMetricName()) {
                name = localService.getServiceId() + "." + name;
            }

            json.writeStringField("name", name);
            json.writeStringField("group", commandMetrics.getCommandGroup().name());
            json.writeNumberField("currentTime", System.currentTimeMillis());

            // circuit breaker
            if (circuitBreaker == null) {
                // circuit breaker is disabled and thus never open
                json.writeBooleanField("isCircuitBreakerOpen", false);
            } else {
                json.writeBooleanField("isCircuitBreakerOpen", circuitBreaker.isOpen());
            }
            HystrixCommandMetrics.HealthCounts healthCounts = commandMetrics.getHealthCounts();
            json.writeNumberField("errorPercentage", healthCounts.getErrorPercentage());
            json.writeNumberField("errorCount", healthCounts.getErrorCount());
            json.writeNumberField("requestCount", healthCounts.getTotalRequests());

            // rolling counters
            json.writeNumberField("rollingCountCollapsedRequests",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.COLLAPSED));
            json.writeNumberField("rollingCountExceptionsThrown",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.EXCEPTION_THROWN));
            json.writeNumberField("rollingCountFailure",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.FAILURE));
            json.writeNumberField("rollingCountFallbackFailure",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.FALLBACK_FAILURE));
            json.writeNumberField("rollingCountFallbackRejection",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.FALLBACK_REJECTION));
            json.writeNumberField("rollingCountFallbackSuccess",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.FALLBACK_SUCCESS));
            json.writeNumberField("rollingCountResponsesFromCache",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.RESPONSE_FROM_CACHE));
            json.writeNumberField("rollingCountSemaphoreRejected",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.SEMAPHORE_REJECTED));
            json.writeNumberField("rollingCountShortCircuited",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.SHORT_CIRCUITED));
            json.writeNumberField("rollingCountSuccess",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.SUCCESS));
            json.writeNumberField("rollingCountThreadPoolRejected",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.THREAD_POOL_REJECTED));
            json.writeNumberField("rollingCountTimeout",
                    commandMetrics.getRollingCount(HystrixRollingNumberEvent.TIMEOUT));

            json.writeNumberField("currentConcurrentExecutionCount",
                    commandMetrics.getCurrentConcurrentExecutionCount());

            // latency percentiles
            json.writeNumberField("latencyExecute_mean", commandMetrics.getExecutionTimeMean());
            json.writeObjectFieldStart("latencyExecute");
            json.writeNumberField("0", commandMetrics.getExecutionTimePercentile(0));
            json.writeNumberField("25", commandMetrics.getExecutionTimePercentile(25));
            json.writeNumberField("50", commandMetrics.getExecutionTimePercentile(50));
            json.writeNumberField("75", commandMetrics.getExecutionTimePercentile(75));
            json.writeNumberField("90", commandMetrics.getExecutionTimePercentile(90));
            json.writeNumberField("95", commandMetrics.getExecutionTimePercentile(95));
            json.writeNumberField("99", commandMetrics.getExecutionTimePercentile(99));
            json.writeNumberField("99.5", commandMetrics.getExecutionTimePercentile(99.5));
            json.writeNumberField("100", commandMetrics.getExecutionTimePercentile(100));
            json.writeEndObject();
            //
            json.writeNumberField("latencyTotal_mean", commandMetrics.getTotalTimeMean());
            json.writeObjectFieldStart("latencyTotal");
            json.writeNumberField("0", commandMetrics.getTotalTimePercentile(0));
            json.writeNumberField("25", commandMetrics.getTotalTimePercentile(25));
            json.writeNumberField("50", commandMetrics.getTotalTimePercentile(50));
            json.writeNumberField("75", commandMetrics.getTotalTimePercentile(75));
            json.writeNumberField("90", commandMetrics.getTotalTimePercentile(90));
            json.writeNumberField("95", commandMetrics.getTotalTimePercentile(95));
            json.writeNumberField("99", commandMetrics.getTotalTimePercentile(99));
            json.writeNumberField("99.5", commandMetrics.getTotalTimePercentile(99.5));
            json.writeNumberField("100", commandMetrics.getTotalTimePercentile(100));
            json.writeEndObject();

            // property values for reporting what is actually seen by the command
            // rather than what was set somewhere
            HystrixCommandProperties commandProperties = commandMetrics.getProperties();

            json.writeNumberField("propertyValue_circuitBreakerRequestVolumeThreshold",
                    commandProperties.circuitBreakerRequestVolumeThreshold().get());
            json.writeNumberField("propertyValue_circuitBreakerSleepWindowInMilliseconds",
                    commandProperties.circuitBreakerSleepWindowInMilliseconds().get());
            json.writeNumberField("propertyValue_circuitBreakerErrorThresholdPercentage",
                    commandProperties.circuitBreakerErrorThresholdPercentage().get());
            json.writeBooleanField("propertyValue_circuitBreakerForceOpen",
                    commandProperties.circuitBreakerForceOpen().get());
            json.writeBooleanField("propertyValue_circuitBreakerForceClosed",
                    commandProperties.circuitBreakerForceClosed().get());
            json.writeBooleanField("propertyValue_circuitBreakerEnabled",
                    commandProperties.circuitBreakerEnabled().get());

            json.writeStringField("propertyValue_executionIsolationStrategy",
                    commandProperties.executionIsolationStrategy().get().name());
            json.writeNumberField("propertyValue_executionIsolationThreadTimeoutInMilliseconds",
                    commandProperties.executionIsolationThreadTimeoutInMilliseconds().get());
            json.writeBooleanField("propertyValue_executionIsolationThreadInterruptOnTimeout",
                    commandProperties.executionIsolationThreadInterruptOnTimeout().get());
            json.writeStringField("propertyValue_executionIsolationThreadPoolKeyOverride",
                    commandProperties.executionIsolationThreadPoolKeyOverride().get());
            json.writeNumberField("propertyValue_executionIsolationSemaphoreMaxConcurrentRequests",
                    commandProperties.executionIsolationSemaphoreMaxConcurrentRequests().get());
            json.writeNumberField("propertyValue_fallbackIsolationSemaphoreMaxConcurrentRequests",
                    commandProperties.fallbackIsolationSemaphoreMaxConcurrentRequests().get());

            // TODO
            /*
             * The following are commented out as these rarely change and are verbose
             * for streaming for something people don't change. We could perhaps allow
             * a property or request argument to include these.
             */

            // json.put("propertyValue_metricsRollingPercentileEnabled",
            // commandProperties.metricsRollingPercentileEnabled().get());
            // json.put("propertyValue_metricsRollingPercentileBucketSize",
            // commandProperties.metricsRollingPercentileBucketSize().get());
            // json.put("propertyValue_metricsRollingPercentileWindow",
            // commandProperties.metricsRollingPercentileWindowInMilliseconds().get());
            // json.put("propertyValue_metricsRollingPercentileWindowBuckets",
            // commandProperties.metricsRollingPercentileWindowBuckets().get());
            // json.put("propertyValue_metricsRollingStatisticalWindowBuckets",
            // commandProperties.metricsRollingStatisticalWindowBuckets().get());
            json.writeNumberField("propertyValue_metricsRollingStatisticalWindowInMilliseconds",
                    commandProperties.metricsRollingStatisticalWindowInMilliseconds().get());

            json.writeBooleanField("propertyValue_requestCacheEnabled",
                    commandProperties.requestCacheEnabled().get());
            json.writeBooleanField("propertyValue_requestLogEnabled",
                    commandProperties.requestLogEnabled().get());

            json.writeNumberField("reportingHosts", 1); // this will get summed across
            // all instances in a cluster

            json.writeEndObject(); // end data attribute
            json.writeEndObject();
            json.close();

            // output
            this.jsonMetrics.add(jsonString.getBuffer().toString());
        }

        // thread pool metrics
        for (HystrixThreadPoolMetrics threadPoolMetrics : HystrixThreadPoolMetrics.getInstances()) {
            HystrixThreadPoolKey key = threadPoolMetrics.getThreadPoolKey();

            StringWriter jsonString = new StringWriter();
            JsonGenerator json = this.jsonFactory.createGenerator(jsonString);
            json.writeStartObject();

            addServiceData(json, localService);
            json.writeObjectFieldStart("data");

            json.writeStringField("type", "HystrixThreadPool");
            json.writeStringField("name", key.name());
            json.writeNumberField("currentTime", System.currentTimeMillis());

            json.writeNumberField("currentActiveCount", threadPoolMetrics.getCurrentActiveCount().intValue());
            json.writeNumberField("currentCompletedTaskCount",
                    threadPoolMetrics.getCurrentCompletedTaskCount().longValue());
            json.writeNumberField("currentCorePoolSize", threadPoolMetrics.getCurrentCorePoolSize().intValue());
            json.writeNumberField("currentLargestPoolSize",
                    threadPoolMetrics.getCurrentLargestPoolSize().intValue());
            json.writeNumberField("currentMaximumPoolSize",
                    threadPoolMetrics.getCurrentMaximumPoolSize().intValue());
            json.writeNumberField("currentPoolSize", threadPoolMetrics.getCurrentPoolSize().intValue());
            json.writeNumberField("currentQueueSize", threadPoolMetrics.getCurrentQueueSize().intValue());
            json.writeNumberField("currentTaskCount", threadPoolMetrics.getCurrentTaskCount().longValue());
            json.writeNumberField("rollingCountThreadsExecuted",
                    threadPoolMetrics.getRollingCountThreadsExecuted());
            json.writeNumberField("rollingMaxActiveThreads", threadPoolMetrics.getRollingMaxActiveThreads());

            json.writeNumberField("propertyValue_queueSizeRejectionThreshold",
                    threadPoolMetrics.getProperties().queueSizeRejectionThreshold().get());
            json.writeNumberField("propertyValue_metricsRollingStatisticalWindowInMilliseconds",
                    threadPoolMetrics.getProperties().metricsRollingStatisticalWindowInMilliseconds().get());

            json.writeNumberField("reportingHosts", 1); // this will get summed across
            // all instances in a cluster

            json.writeEndObject(); // end of data object
            json.writeEndObject();
            json.close();
            // output to stream
            this.jsonMetrics.add(jsonString.getBuffer().toString());
        }
    } catch (Exception ex) {
        log.error("Error adding metrics to queue", ex);
    }
}

From source file:com.greplin.gec.GecLog4jAppender.java

/**
 * Writes a formatted exception to the given writer.
 *
 * @param message   the log message//from  ww  w.  j a  v a2 s .c  o  m
 * @param throwable the exception
 * @param level     the error level
 * @param out       the destination
 * @throws IOException if there are IO errors in the destination
 */
void writeFormattedException(final String message, final Throwable throwable, final Level level,
        final Writer out) throws IOException {
    JsonGenerator generator = new JsonFactory().createJsonGenerator(out);

    Throwable rootThrowable = throwable;
    while (this.passthroughExceptions.contains(rootThrowable.getClass()) && rootThrowable.getCause() != null) {
        rootThrowable = rootThrowable.getCause();
    }

    generator.writeStartObject();
    generator.writeStringField("project", this.project);
    generator.writeStringField("environment", this.environment);
    generator.writeStringField("serverName", this.serverName);
    generator.writeStringField("backtrace", ExceptionUtils.getStackTrace(throwable));
    generator.writeStringField("message", rootThrowable.getMessage());
    generator.writeStringField("logMessage", message);
    generator.writeStringField("type", rootThrowable.getClass().getName());
    if (level != Level.ERROR) {
        generator.writeStringField("errorLevel", level.toString());
    }
    writeContext(generator);
    generator.writeEndObject();
    generator.close();
}

From source file:com.strategicgains.hyperexpress.serialization.siren.jackson.SirenResourceSerializer.java

private void writeEntities(Resource resource, JsonGenerator jgen) throws JsonGenerationException, IOException {
    Map<String, List<Resource>> entities = resource.getResources();

    if (entities == null || entities.isEmpty())
        return;/*from   ww  w . j a  v  a 2  s .com*/

    jgen.writeArrayFieldStart(ENTITIES);

    for (Entry<String, List<Resource>> entry : entities.entrySet()) {
        for (Resource r : entry.getValue()) {
            jgen.writeStartObject();
            jgen.writeArrayFieldStart("rel");
            jgen.writeString(entry.getKey());
            jgen.writeEndArray();
            renderJson((SirenResource) r, jgen);
            jgen.writeEndObject();
        }
    }

    jgen.writeEndArray();
}

From source file:org.springframework.cloud.netflix.metrics.atlas.AtlasMetricObserver.java

private int writeMetrics(JsonGenerator gen, List<Metric> metrics) throws IOException {
    int totalMetricsInBatch = 0;
    gen.writeArrayFieldStart("metrics");

    for (Metric m : metrics) {
        if (!validTags(m.getConfig().getTags()))
            continue;

        if (!Number.class.isAssignableFrom(m.getValue().getClass()))
            continue;

        gen.writeStartObject();// www .ja va2  s. co m

        gen.writeObjectFieldStart("tags");
        gen.writeStringField("name", m.getConfig().getName());
        for (Tag tag : m.getConfig().getTags())
            gen.writeStringField(tag.getKey(), tag.getValue());
        gen.writeEndObject();

        gen.writeNumberField("start", m.getTimestamp());
        gen.writeNumberField("value", m.getNumberValue().doubleValue());

        gen.writeEndObject();

        totalMetricsInBatch++;
    }

    gen.writeEndArray();
    return totalMetricsInBatch;
}

From source file:org.emfjson.jackson.streaming.StreamWriter.java

public void generate(final JsonGenerator generator, final EObject object) throws IOException {
    prepare(generator, object.eResource());

    final EClass eClass = object.eClass();
    final List<EAttribute> attributes = cache.getAttributes(eClass);
    final List<EReference> references = cache.getReferences(eClass);

    generator.writeStartObject();

    if (options.serializeTypes) {
        generator.writeStringField(EJS_TYPE_KEYWORD, cache.getHref(null, eClass));
    }/*from w w  w .j a  va2 s. c o m*/

    if (object.eResource() instanceof UuidResource) {
        String id = ((UuidResource) object.eResource()).getID(object);
        if (id != null) {
            generator.writeStringField(EJS_UUID_ANNOTATION, id);
        }
    } else {
        if (options.useId) {
            String id = object.eResource().getURIFragment(object);
            if (id != null) {
                generator.writeStringField(EJS_UUID_ANNOTATION, id);
            }
        }
    }

    for (final EAttribute attribute : attributes) {
        if (isCandidate(object, attribute)) {
            final String key = cache.getKey(attribute);
            final Object value = object.eGet(attribute);

            if (isFeatureMap(attribute)) {
                serializeFeatureMap(generator, attribute, object);
            } else {
                values.serialize(generator, key, attribute, value);
            }
        }
    }

    for (final EReference reference : references) {
        if (isCandidate(object, reference)) {
            final Object value = object.eGet(reference);
            final String key = cache.getKey(reference);

            if (isMapEntry(reference.getEReferenceType())) {
                serializeMapEntry(generator, key, reference, value);
            } else if (!reference.isContainment()) {
                referenceWriter.serialize(generator, key, reference, value);
            } else {
                serializeContainment(generator, key, reference, object, value);
            }
        }
    }

    generator.writeEndObject();
}

From source file:com.googlecode.jmxtrans.model.output.StackdriverWriter.java

/**
 * Take query results, make a JSON String
 * //from  w  w w .  j  a va 2 s .  co  m
 * @param results List of Result objects
 * @return a String containing a JSON message, or null if there are no values to report
 * 
 * @throws IOException if there is some problem generating the JSON, should be uncommon
 */
private String getGatewayMessage(final List<Result> results) throws IOException {
    int valueCount = 0;
    Writer writer = new StringWriter();
    JsonGenerator g = jsonFactory.createGenerator(writer);
    g.writeStartObject();
    g.writeNumberField("timestamp", System.currentTimeMillis() / 1000);
    g.writeNumberField("proto_version", STACKDRIVER_PROTOCOL_VERSION);
    g.writeArrayFieldStart("data");

    List<String> typeNames = this.getTypeNames();

    for (Result metric : results) {
        Map<String, Object> values = metric.getValues();
        if (values != null) {
            for (Entry<String, Object> entry : values.entrySet()) {
                if (isNumeric(entry.getValue())) {
                    // we have a numeric value, write a value into the message

                    StringBuilder nameBuilder = new StringBuilder();

                    // put the prefix if set
                    if (this.prefix != null) {
                        nameBuilder.append(prefix);
                        nameBuilder.append(".");
                    }

                    // put the class name or its alias if available
                    if (!metric.getKeyAlias().isEmpty()) {
                        nameBuilder.append(metric.getKeyAlias());

                    } else {
                        nameBuilder.append(metric.getClassName());
                    }

                    // Wildcard "typeNames" substitution
                    String typeName = com.googlecode.jmxtrans.model.naming.StringUtils
                            .cleanupStr(TypeNameValuesStringBuilder.getDefaultBuilder().build(typeNames,
                                    metric.getTypeName()));
                    if (typeName != null && typeName.length() > 0) {
                        nameBuilder.append(".");
                        nameBuilder.append(typeName);
                    }

                    // add the attribute name
                    nameBuilder.append(".");
                    nameBuilder.append(metric.getAttributeName());

                    // put the value name if it differs from the attribute name
                    if (!entry.getKey().equals(metric.getAttributeName())) {
                        nameBuilder.append(".");
                        nameBuilder.append(entry.getKey());
                    }

                    // check for Float/Double NaN since these will cause the message validation to fail 
                    if (entry.getValue() instanceof Float && ((Float) entry.getValue()).isNaN()) {
                        logger.info("Metric value for " + nameBuilder.toString() + " is NaN, skipping");
                        continue;
                    }

                    if (entry.getValue() instanceof Double && ((Double) entry.getValue()).isNaN()) {
                        logger.info("Metric value for " + nameBuilder.toString() + " is NaN, skipping");
                        continue;
                    }

                    valueCount++;
                    g.writeStartObject();

                    g.writeStringField("name", nameBuilder.toString());

                    g.writeNumberField("value", Double.valueOf(entry.getValue().toString()));

                    // if the metric is attached to an instance, include that in the message
                    if (instanceId != null && !instanceId.isEmpty()) {
                        g.writeStringField("instance", instanceId);
                    }
                    g.writeNumberField("collected_at", metric.getEpoch() / 1000);
                    g.writeEndObject();
                }
            }
        }
    }

    g.writeEndArray();
    g.writeEndObject();
    g.flush();
    g.close();

    // return the message if there are any values to report
    if (valueCount > 0) {
        return writer.toString();
    } else {
        return null;
    }
}