Create ProtobufSchema object from .descriptor file

DynamicSchemaUtil.java

package com.example.jackson.protobuf;

import com.fasterxml.jackson.dataformat.protobuf.schema.FieldType;
import com.fasterxml.jackson.dataformat.protobuf.schema.ProtobufEnum;
import com.fasterxml.jackson.dataformat.protobuf.schema.ProtobufField;
import com.fasterxml.jackson.dataformat.protobuf.schema.ProtobufMessage;
import com.fasterxml.jackson.dataformat.protobuf.schema.ProtobufSchema;
import com.github.os72.protobuf.dynamic.DynamicSchema;
import com.google.protobuf.Descriptors;
import com.squareup.protoparser.DataType;
import com.squareup.protoparser.FieldElement;
import com.squareup.protoparser.OptionElement;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static com.squareup.protoparser.FieldElement.Label.OPTIONAL;
import static com.squareup.protoparser.FieldElement.Label.REPEATED;
import static com.squareup.protoparser.FieldElement.Label.REQUIRED;

public class DynamicSchemaUtil
{
    private final static Map<Descriptors.FieldDescriptor.Type, FieldType> typeMap;
    private final static Map<Descriptors.FieldDescriptor.Type, DataType> typeMap2;

    static {
        typeMap = new HashMap();
        typeMap.put(Descriptors.FieldDescriptor.Type.DOUBLE, FieldType.DOUBLE);
        typeMap.put(Descriptors.FieldDescriptor.Type.FLOAT, FieldType.FLOAT);
        typeMap.put(Descriptors.FieldDescriptor.Type.INT32, FieldType.VINT32_Z);
        typeMap.put(Descriptors.FieldDescriptor.Type.INT64, FieldType.VINT64_Z);
        typeMap.put(Descriptors.FieldDescriptor.Type.UINT32, FieldType.VINT32_STD);
        typeMap.put(Descriptors.FieldDescriptor.Type.UINT64, FieldType.VINT64_STD);
        typeMap.put(Descriptors.FieldDescriptor.Type.FIXED32, FieldType.FIXINT32);
        typeMap.put(Descriptors.FieldDescriptor.Type.FIXED64, FieldType.FIXINT64);
        typeMap.put(Descriptors.FieldDescriptor.Type.BOOL, FieldType.BOOLEAN);
        typeMap.put(Descriptors.FieldDescriptor.Type.STRING, FieldType.STRING);
        typeMap.put(Descriptors.FieldDescriptor.Type.BYTES, FieldType.BYTES);
        typeMap.put(Descriptors.FieldDescriptor.Type.ENUM, FieldType.ENUM);
        typeMap.put(Descriptors.FieldDescriptor.Type.MESSAGE, FieldType.MESSAGE);

        typeMap2 = new HashMap();
        typeMap2.put(Descriptors.FieldDescriptor.Type.BOOL, DataType.ScalarType.BOOL);
        typeMap2.put(Descriptors.FieldDescriptor.Type.BYTES, DataType.ScalarType.BYTES);
        typeMap2.put(Descriptors.FieldDescriptor.Type.DOUBLE, DataType.ScalarType.DOUBLE);
        typeMap2.put(Descriptors.FieldDescriptor.Type.FLOAT, DataType.ScalarType.FLOAT);
        typeMap2.put(Descriptors.FieldDescriptor.Type.FIXED32, DataType.ScalarType.FIXED32);
        typeMap2.put(Descriptors.FieldDescriptor.Type.FIXED64, DataType.ScalarType.FIXED64);
        typeMap2.put(Descriptors.FieldDescriptor.Type.INT32, DataType.ScalarType.INT32);
        typeMap2.put(Descriptors.FieldDescriptor.Type.INT64, DataType.ScalarType.INT64);
        typeMap2.put(Descriptors.FieldDescriptor.Type.SFIXED32, DataType.ScalarType.SFIXED32);
        typeMap2.put(Descriptors.FieldDescriptor.Type.SFIXED64, DataType.ScalarType.SFIXED64);
        typeMap2.put(Descriptors.FieldDescriptor.Type.SINT32, DataType.ScalarType.SINT32);
        typeMap2.put(Descriptors.FieldDescriptor.Type.SINT64, DataType.ScalarType.SINT64);
        typeMap2.put(Descriptors.FieldDescriptor.Type.STRING, DataType.ScalarType.STRING);
        typeMap2.put(Descriptors.FieldDescriptor.Type.UINT32, DataType.ScalarType.UINT32);
        typeMap2.put(Descriptors.FieldDescriptor.Type.UINT64, DataType.ScalarType.UINT64);
    }

    public static FieldElement.Label getLabel(Descriptors.FieldDescriptor d)
    {
        FieldElement.Label label = REQUIRED;
        if (d.isOptional()) {
            label = OPTIONAL;
        } else if (d.isRequired()) {
            label = REQUIRED;
        } else if (d.isRepeated()) {
            label = REPEATED;
        }
        return label;
    }

    public static ProtobufEnum buildProtobufEnum(Descriptors.FieldDescriptor d)
    {
        Descriptors.EnumDescriptor enumField = d.getEnumType();
        Map<String, Integer> enumFields = new HashMap();
        List<Descriptors.EnumValueDescriptor> values = enumField.getValues();
        boolean standardIndexing = true;
        ProtobufEnum et = new ProtobufEnum(d.getName(), enumFields, standardIndexing);
        return et;
    }

    public static ProtobufMessage buildProtobufMessage(Descriptors.Descriptor messageDescriptor)
    {
        List<Descriptors.FieldDescriptor> fieldDescriptors = messageDescriptor.getFields();
        ProtobufField[] fields = new ProtobufField[fieldDescriptors.size()];
        for (Descriptors.FieldDescriptor d : fieldDescriptors) {
            ProtobufField f;
            FieldElement.Label label = getLabel(d);
            Integer tag = d.getNumber();
            // type
            if (d.getType() == Descriptors.FieldDescriptor.Type.ENUM) {
                // enum
                // field
                FieldElement.Builder builder = FieldElement.builder();
                FieldElement nativeField = builder.label(getLabel(d))
                                                  .type(DataType.NamedType.create(d.getJsonName()))
                                                  .name(d.getName())
                                                  .tag(tag)
                                                  .build();
                // value
                ProtobufEnum et = buildProtobufEnum(d);
                f = new ProtobufField(nativeField, et);
          } else if (d.getType() == Descriptors.FieldDescriptor.Type.MESSAGE) {
                // Message
                FieldElement.Builder builder = FieldElement.builder();
                FieldElement nativeField = builder.label(getLabel(d))
                                                  .type(DataType.NamedType.create(d.getJsonName()))
                                                  .name(d.getName())
                                                  .tag(tag)
                                                  .build();
                // value
                ProtobufMessage nestedMsg = buildProtobufMessage(d.getMessageType());
                f = new ProtobufField(nativeField, nestedMsg);
            } else if (d.getType() == Descriptors.FieldDescriptor.Type.GROUP) {
                System.out.println("not supported");
                continue;
            } else {
                // scalar
                // field
                FieldElement.Builder builder = FieldElement.builder();
                FieldElement nativeField = builder.label(label)
                                                  .type(typeMap2.get(d.getType()))
                                                  .name(d.getName())
                                                  .tag(tag)
                                                  .addOption(OptionElement.create("packed", OptionElement.Kind.BOOLEAN, d.isPacked()))
                                                  .build();
                // value
                FieldType t = typeMap.get(d.getType());
                f = new ProtobufField(nativeField, t);
            }
            fields[d.getIndex()] = f;
        }
        return new ProtobufMessage(messageDescriptor.getName(), fields);
    }

    public static ProtobufSchema toProtobufSchema(DynamicSchema dynamicSchema, String rootType)
    {
        Descriptors.Descriptor messageDescriptor = dynamicSchema.getMessageDescriptor(rootType);
        ProtobufMessage msg = buildProtobufMessage(messageDescriptor);
        return new ProtobufSchema(msg);
    }

    public static ProtobufSchema toProtobufSchema(DynamicSchema dynamicSchema)
    {
        String firstType = (String) dynamicSchema.getMessageTypes().toArray()[0];
        return toProtobufSchema(dynamicSchema, firstType);
    }
}