MetricBuilder.java

/*
 * Copyright 2013 Proofpoint Inc.
 *
 *    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.
 */
package org.kairosdb.client.builder;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import org.kairosdb.client.builder.aggregator.CustomAggregator;
import org.kairosdb.client.builder.grouper.CustomGrouper;
import org.kairosdb.client.serializer.CustomAggregatorSerializer;
import org.kairosdb.client.serializer.CustomGrouperSerializer;
import org.kairosdb.client.serializer.DataPointSerializer;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import static com.google.common.base.Preconditions.checkState;

/**
 * Builder used to create the JSON to push metrics to KairosDB.
 */
public class MetricBuilder
{
	private List<Metric> metrics = new ArrayList<Metric>();
	private transient Gson mapper;

	private MetricBuilder()
	{
		GsonBuilder builder = new GsonBuilder();
		builder.registerTypeAdapter(CustomAggregator.class, new CustomAggregatorSerializer());
		builder.registerTypeAdapter(CustomGrouper.class, new CustomGrouperSerializer());
		builder.registerTypeAdapter(DataPoint.class, new DataPointSerializer());
		mapper = builder.create();
	}

	/**
	 * Returns a new metric builder.
	 *
	 * @return metric builder
	 */
	public static MetricBuilder getInstance()
	{
		return new MetricBuilder();
	}

	/**
	 * Adds a metric to the builder.
	 *
	 * @param metricName metric name
	 * @return the new metric
	 */
	public Metric addMetric(String metricName)
	{
		Metric metric = new Metric(metricName);
		metrics.add(metric);
		return metric;
	}

	/**
	 * Adds a metric to the builder with a customer type.
	 *
	 * @param metricName    metric name
	 * @param registeredType type used to deserialize the json on the server
	 * @return the new metric
	 */
	public Metric addMetric(String metricName, String registeredType)
	{
		Metric metric = new Metric(metricName, registeredType);
		metrics.add(metric);
		return metric;
	}

	/**
	 * Returns a list of metrics added to the builder.
	 *
	 * @return list of metrics
	 */
	public List<Metric> getMetrics()
	{
		return metrics;
	}

	/**
	 * Returns the JSON string built by the builder. This is the JSON that can be used by the client add metrics.
	 *
	 * @return JSON
	 * @throws IOException if metrics cannot be converted to JSON
	 */
	public String build() throws IOException
	{
		for (Metric metric : metrics)
		{
			// verify that there is at least one tag for each metric
			checkState(metric.getTags().size() > 0, metric.getName() + " must contain at least one tag.");
		}
		return mapper.toJson(metrics);
	}
}