com.turn.shapeshifter.AutoSerializer.java Source code

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Here is the source code for com.turn.shapeshifter.AutoSerializer.java

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/**
 * Copyright 2012, 2013 Turn, 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 com.turn.shapeshifter;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.BooleanNode;
import com.fasterxml.jackson.databind.node.DoubleNode;
import com.fasterxml.jackson.databind.node.IntNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.LongNode;
import com.fasterxml.jackson.databind.node.NullNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.TextNode;
import com.google.protobuf.Descriptors;
import com.google.protobuf.Message;
import com.google.protobuf.Descriptors.EnumValueDescriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;

/**
 * Default implementation of {@link Serializer}.
 *
 * @author jsilland
 */
final class AutoSerializer implements Serializer {

    private final Descriptors.Descriptor descriptor;

    AutoSerializer(Descriptors.Descriptor descriptor) {
        this.descriptor = descriptor;
    }

    /**
     * {@inheritDoc}
     * @throws SerializationException
     */
    @Override
    public JsonNode serialize(Message message, ReadableSchemaRegistry registry) throws SerializationException {
        ObjectNode object = new ObjectNode(JsonNodeFactory.instance);

        for (Descriptors.FieldDescriptor field : descriptor.getFields()) {
            String propertyName = AutoSchema.PROTO_FIELD_CASE_FORMAT.to(AutoSchema.JSON_FIELD_CASE_FORMAT,
                    field.getName());
            if (field.isRepeated()) {
                if (message.getRepeatedFieldCount(field) > 0) {
                    ArrayNode array = serializeRepeatedField(message, field, registry);
                    if (array.size() != 0) {
                        object.put(propertyName, array);
                    }
                }
            } else if (message.hasField(field)) {
                Object value = message.getField(field);
                JsonNode fieldNode = serializeValue(value, field, registry);
                if (!fieldNode.isNull()) {
                    object.put(propertyName, fieldNode);
                }
            }
        }

        if (object.size() == 0) {
            return NullNode.instance;
        }

        return object;
    }

    /**
     * Serializes a repeated field.
     *
     * @param message the message being serialized
     * @param registry a registry of schemas, for enclosed object types
     * @param field the descriptor of the repeated field to serialize
     * @param count the count of repeated items in the field
     * @return the JSON representation of the serialized
     * @throws SerializationException
     */
    private ArrayNode serializeRepeatedField(Message message, FieldDescriptor field,
            ReadableSchemaRegistry registry) throws SerializationException {
        ArrayNode array = new ArrayNode(JsonNodeFactory.instance);
        int count = message.getRepeatedFieldCount(field);
        for (int i = 0; i < count; i++) {
            Object value = message.getRepeatedField(field, i);
            JsonNode valueNode = serializeValue(value, field, registry);
            if (!valueNode.isNull()) {
                array.add(valueNode);
            }
        }
        return array;
    }

    /**
     * Returns the JSON representation of the value of a message's field.
     *
     * @param value the value to represent in JSON
     * @param field the descriptor of the value's field.
     * @param schemas a container for object schemas to use for formatting
     * fields that refer to other messages
     * @throws SerializationException
     */
    private JsonNode serializeValue(Object value, FieldDescriptor field, ReadableSchemaRegistry registry)
            throws SerializationException {
        JsonNode valueNode = NullNode.instance;
        switch (field.getType()) {
        case BOOL:
            valueNode = BooleanNode.valueOf((Boolean) value);
            break;
        case BYTES:
            break;
        case DOUBLE:
            valueNode = new DoubleNode((Double) value);
            break;
        case ENUM:
            EnumValueDescriptor enumValueDescriptor = (EnumValueDescriptor) value;
            String enumValue = enumValueDescriptor.getName();
            String convertedValue = AutoSchema.PROTO_ENUM_CASE_FORMAT.to(AutoSchema.JSON_ENUM_CASE_FORMAT,
                    enumValue);
            valueNode = new TextNode(convertedValue);
            break;
        case FLOAT:
            valueNode = new DoubleNode((Float) value);
            break;
        case GROUP:
            break;
        case FIXED32:
        case INT32:
        case SFIXED32:
        case SINT32:
        case UINT32:
            valueNode = new IntNode((Integer) value);
            break;
        case FIXED64:
        case INT64:
        case SFIXED64:
        case SINT64:
        case UINT64:
            valueNode = new LongNode((Long) value);
            break;
        case MESSAGE:
            Message messageValue = (Message) value;
            try {
                valueNode = registry.get(messageValue.getDescriptorForType()).getSerializer()
                        .serialize(messageValue, registry);
                valueNode = valueNode.size() == 0 ? NullNode.instance : valueNode;
            } catch (SchemaObtentionException soe) {
                throw new SerializationException(soe);
            }
            break;
        case STRING:
            valueNode = new TextNode((String) value);
            break;
        default:
            break;
        }
        return valueNode;
    }
}