MetricGroupSerialization.java

/*
 * Copyright (c) 2015 Spotify AB.
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.spotify.heroic.metric;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.google.common.collect.ImmutableList;

import java.io.IOException;

public class MetricGroupSerialization {
    public static class Deserializer extends JsonDeserializer<MetricGroup> {
        @Override
        public MetricGroup deserialize(JsonParser p, DeserializationContext c)
            throws IOException, JsonProcessingException {

            if (p.getCurrentToken() != JsonToken.START_ARRAY) {
                throw c.mappingException("Expected start of array");
            }

            final Long timestamp;

            {
                if (p.nextToken() != JsonToken.VALUE_NUMBER_INT) {
                    throw c.mappingException("Expected number (timestamp)");
                }

                timestamp = p.readValueAs(Long.class);
            }

            if (p.nextToken() != JsonToken.START_ARRAY) {
                throw c.mappingException("Expected start of array");
            }

            final ImmutableList.Builder<MetricCollection> groups = ImmutableList.builder();

            while (p.nextToken() == JsonToken.START_OBJECT) {
                groups.add(p.readValueAs(MetricCollection.class));
            }

            if (p.getCurrentToken() != JsonToken.END_ARRAY) {
                throw c.mappingException("Expected end of array");
            }

            if (p.getCurrentToken() != JsonToken.END_ARRAY) {
                throw c.mappingException("Expected end of array");
            }

            return new MetricGroup(timestamp, groups.build());
        }
    }

    public static class Serializer extends JsonSerializer<MetricGroup> {
        @Override
        public void serialize(MetricGroup d, JsonGenerator g, SerializerProvider provider)
            throws IOException, JsonProcessingException {
            g.writeStartArray();
            g.writeNumber(d.getTimestamp());

            g.writeStartArray();

            for (final MetricCollection group : d.getGroups()) {
                g.writeObject(group);
            }

            g.writeEndArray();
            g.writeEndArray();
        }
    }
}