com.cloudera.exhibit.server.json.ExhibitSerializer.java Source code

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Here is the source code for com.cloudera.exhibit.server.json.ExhibitSerializer.java

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/*
 * Copyright (c) 2014, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. 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
 *
 * This software 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.cloudera.exhibit.server.json;

import com.cloudera.exhibit.core.Exhibit;
import com.cloudera.exhibit.core.ExhibitDescriptor;
import com.cloudera.exhibit.core.Obs;
import com.cloudera.exhibit.core.ObsDescriptor;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

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

public class ExhibitSerializer extends JsonSerializer<Exhibit> {

    @Override
    public void serialize(Exhibit exhibit, JsonGenerator gen, SerializerProvider provider) throws IOException {
        ExhibitDescriptor desc = exhibit.descriptor();
        // start object
        gen.writeStartObject();

        // Write attrs
        gen.writeObjectFieldStart("attrs");
        serializeObs(exhibit.attributes(), exhibit.attributes().descriptor(), gen);
        gen.writeEndObject();

        // Write frame column names
        gen.writeObjectFieldStart("columns");
        for (Map.Entry<String, ObsDescriptor> fd : desc.frames().entrySet()) {
            gen.writeArrayFieldStart(fd.getKey());
            for (ObsDescriptor.Field f : fd.getValue()) {
                // TODO: type info?
                gen.writeString(f.name);
            }
            gen.writeEndArray();
        }
        gen.writeEndObject();

        // Write frame obs
        gen.writeObjectFieldStart("frames");
        for (Map.Entry<String, ObsDescriptor> fd : desc.frames().entrySet()) {
            gen.writeArrayFieldStart(fd.getKey());
            ObsDescriptor od = fd.getValue();
            for (Obs obs : exhibit.frames().get(fd.getKey())) {
                gen.writeStartArray();
                serializeObsArray(obs, fd.getValue(), gen);
                gen.writeEndArray();
            }
            gen.writeEndArray();
        }
        gen.writeEndObject();

        // finish object
        gen.writeEndObject();
    }

    private void serializeObs(Obs obs, ObsDescriptor desc, JsonGenerator gen) throws IOException {
        for (int i = 0; i < desc.size(); i++) {
            ObsDescriptor.Field f = desc.get(i);
            Object value = obs.get(i);
            if (value == null) {
                gen.writeNullField(f.name);
            } else {
                switch (f.type) {
                case STRING:
                    gen.writeStringField(f.name, value.toString());
                    break;
                case BOOLEAN:
                    gen.writeBooleanField(f.name, (Boolean) value);
                    break;
                case INTEGER:
                    gen.writeNumberField(f.name, ((Number) value).intValue());
                    break;
                case FLOAT:
                    gen.writeNumberField(f.name, ((Number) value).floatValue());
                    break;
                case DOUBLE:
                    gen.writeNumberField(f.name, ((Number) value).doubleValue());
                    break;
                case LONG:
                    gen.writeNumberField(f.name, ((Number) value).longValue());
                    break;
                default:
                    throw new UnsupportedOperationException("Unknown type for field: " + f);
                }
            }
        }
    }

    private void serializeObsArray(Obs obs, ObsDescriptor desc, JsonGenerator gen) throws IOException {
        for (int i = 0; i < desc.size(); i++) {
            ObsDescriptor.Field f = desc.get(i);
            Object value = obs.get(i);
            if (value == null) {
                gen.writeNull();
            } else {
                switch (f.type) {
                case STRING:
                    gen.writeString(value.toString());
                    break;
                case BOOLEAN:
                    gen.writeBoolean((Boolean) value);
                    break;
                case INTEGER:
                    gen.writeNumber(((Number) value).intValue());
                    break;
                case FLOAT:
                    gen.writeNumber(((Number) value).floatValue());
                    break;
                case DOUBLE:
                    gen.writeNumber(((Number) value).doubleValue());
                    break;
                case LONG:
                    gen.writeNumber(((Number) value).longValue());
                    break;
                default:
                    throw new UnsupportedOperationException("Unknown type for field: " + f);
                }
            }
        }
    }
}