me.tfeng.toolbox.avro.AvroHelper.java Source code

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/**
 * Copyright 2016 Thomas Feng
 *
 * 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 me.tfeng.toolbox.avro;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;

import org.apache.avro.Protocol;
import org.apache.avro.Schema;
import org.apache.avro.Schema.Field;
import org.apache.avro.Schema.Type;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.IndexedRecord;
import org.apache.avro.io.BinaryDecoder;
import org.apache.avro.io.BinaryEncoder;
import org.apache.avro.io.DecoderFactory;
import org.apache.avro.io.EncoderFactory;
import org.apache.avro.io.JsonDecoder;
import org.apache.avro.io.JsonEncoder;
import org.apache.avro.specific.SpecificData;
import org.apache.avro.specific.SpecificDatumReader;
import org.apache.avro.specific.SpecificDatumWriter;
import org.apache.commons.lang3.ArrayUtils;
import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerator;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;

import me.tfeng.toolbox.common.Constants;

/**
 * @author Thomas Feng (huining.feng@gmail.com)
 */
public class AvroHelper {

    private static final ObjectMapper MAPPER = new ObjectMapper();

    public static JsonNode convertFromSimpleRecord(Schema schema, JsonNode json) throws IOException {
        return convertFromSimpleRecord(schema, json, new JsonNodeFactory(false));
    }

    public static String convertFromSimpleRecord(Schema schema, String json) throws IOException {
        if (json.isEmpty()) {
            return json;
        }
        JsonNode node = MAPPER.readTree(json);
        node = convertFromSimpleRecord(schema, node);
        return node.toString();
    }

    public static JsonNode convertToSimpleRecord(Schema schema, JsonNode json) throws IOException {
        return convertToSimpleRecord(schema, json, new JsonNodeFactory(false));
    }

    public static String convertToSimpleRecord(Schema schema, String json) throws IOException {
        if (json.isEmpty()) {
            return json;
        }
        JsonNode node = MAPPER.readTree(json);
        node = convertToSimpleRecord(schema, node);
        return node.toString();
    }

    public static Object createGenericRequestFromRecord(Schema requestSchema, JsonNode record) throws IOException {
        JsonDecoder jsonDecoder = DecoderFactory.get().jsonDecoder(requestSchema, record.toString());
        return new GenericDatumReader<>(requestSchema, requestSchema).read(null, jsonDecoder);
    }

    public static <T> T createSpecificRequestFromRecord(Class<T> requestClass, JsonNode record) throws IOException {
        JsonDecoder jsonDecoder = DecoderFactory.get().jsonDecoder(getSchema(requestClass), record.toString());
        return new SpecificDatumReader<>(requestClass).read(null, jsonDecoder);
    }

    public static <T> T decodeRecord(Class<T> recordClass, byte[] data) throws IOException {
        DecoderFactory decoderFactory = DecoderFactory.get();
        BinaryDecoder binaryDecoder = decoderFactory.binaryDecoder(data, null);
        SpecificDatumReader<T> datumReader = new SpecificDatumReader<>(getSchema(recordClass));
        return datumReader.read(null, binaryDecoder);
    }

    public static byte[] encodeRecord(IndexedRecord record) throws IOException {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        try {
            EncoderFactory encoderFactory = EncoderFactory.get();
            BinaryEncoder binaryEncoder = encoderFactory.binaryEncoder(stream, null);
            SpecificDatumWriter<IndexedRecord> datumWriter = new SpecificDatumWriter<>(record.getSchema());
            datumWriter.write(record, binaryEncoder);
            binaryEncoder.flush();
        } finally {
            stream.close();
        }
        return stream.toByteArray();
    }

    public static Protocol getProtocol(Class<?> interfaceClass) {
        return new SpecificData(interfaceClass.getClassLoader()).getProtocol(interfaceClass);
    }

    public static Schema getSchema(Class<?> schemaClass) {
        return new SpecificData(schemaClass.getClassLoader()).getSchema(schemaClass);
    }

    public static Schema getSimpleUnionType(Schema union) throws IOException {
        if (union.getType() != Type.UNION) {
            throw new IOException("Schema is not a union type: " + union);
        }
        List<Schema> types = union.getTypes();
        if (types.size() == 2) {
            if (types.get(0).getType() == Type.NULL && types.get(1).getType() != Type.NULL) {
                return types.get(1);
            } else if (types.get(1).getType() == Type.NULL && types.get(0).getType() != Type.NULL) {
                return types.get(0);
            }
        }
        return null;
    }

    public static JsonNode parseSimpleJson(Schema schema, byte[] data) throws IOException {
        if (ArrayUtils.isEmpty(data)) {
            // The method takes no argument; use empty data.
            data = "{}".getBytes(Constants.UTF8);
        }
        JsonNode node = MAPPER.readTree(data);
        return convertFromSimpleRecord(schema, node);
    }

    public static String toJson(IndexedRecord record) throws IOException {
        Schema schema = record.getSchema();
        return toJson(schema, record);
    }

    public static String toJson(Schema schema, Object object) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        JsonGenerator generator = new JsonFactory().createJsonGenerator(outputStream, JsonEncoding.UTF8);
        generator.useDefaultPrettyPrinter();
        SpecificDatumWriter<Object> writer = new SpecificDatumWriter<>(schema);
        JsonEncoder encoder = EncoderFactory.get().jsonEncoder(schema, generator);
        writer.write(object, encoder);
        encoder.flush();
        return outputStream.toString();
    }

    public static <T> T toRecord(Class<T> recordClass, String json) throws IOException {
        Schema schema = getSchema(recordClass);
        json = convertFromSimpleRecord(schema, json);
        SpecificDatumReader<T> reader = new SpecificDatumReader<>(recordClass);
        return reader.read(null, DecoderFactory.get().jsonDecoder(schema, json));
    }

    public static <T> T toRecord(Schema schema, String json) throws IOException {
        json = convertFromSimpleRecord(schema, json);
        SpecificDatumReader<T> reader = new SpecificDatumReader<>(schema);
        return reader.read(null, DecoderFactory.get().jsonDecoder(schema, json));
    }

    public static String toSimpleJson(IndexedRecord record) throws IOException {
        Schema schema = record.getSchema();
        return toSimpleJson(schema, record);
    }

    public static String toSimpleJson(Schema schema, Object object) throws IOException {
        return convertToSimpleRecord(schema, toJson(schema, object));
    }

    private static JsonNode convertFromSimpleRecord(Schema schema, JsonNode json, JsonNodeFactory factory)
            throws IOException {
        if (json.isObject() && schema.getType() == Type.RECORD) {
            ObjectNode node = (ObjectNode) json;
            ObjectNode newNode = factory.objectNode();
            for (Field field : schema.getFields()) {
                String fieldName = field.name();
                if (node.has(fieldName)) {
                    newNode.set(fieldName, convertFromSimpleRecord(field.schema(), node.get(fieldName), factory));
                } else if (field.defaultValue() != null) {
                    newNode.set(fieldName, MAPPER.readTree(field.defaultValue().toString()));
                } else {
                    newNode.set(fieldName, factory.nullNode());
                }
            }
            return newNode;
        } else if (json.isObject() && schema.getType() == Type.MAP) {
            ObjectNode node = (ObjectNode) json;
            ObjectNode newNode = factory.objectNode();
            Schema valueType = schema.getValueType();
            Iterator<Entry<String, JsonNode>> entries = node.fields();
            while (entries.hasNext()) {
                Entry<String, JsonNode> entry = entries.next();
                newNode.set(entry.getKey(), convertFromSimpleRecord(valueType, entry.getValue(), factory));
            }
            return newNode;
        } else if (schema.getType() == Type.UNION) {
            Schema type = getSimpleUnionType(schema);
            if (type == null) {
                if (json.isNull()) {
                    return json;
                } else {
                    ObjectNode node = (ObjectNode) json;
                    Entry<String, JsonNode> entry = node.fields().next();
                    for (Schema unionType : schema.getTypes()) {
                        if (unionType.getFullName().equals(entry.getKey())) {
                            ObjectNode newNode = factory.objectNode();
                            newNode.set(entry.getKey(),
                                    convertFromSimpleRecord(unionType, entry.getValue(), factory));
                            return newNode;
                        }
                    }
                    throw new IOException("Unable to get schema for type " + entry.getKey() + " in union");
                }
            } else if (json.isNull()) {
                return json;
            } else {
                ObjectNode newNode = factory.objectNode();
                newNode.set(type.getFullName(), convertFromSimpleRecord(type, json, factory));
                return newNode;
            }
        } else if (json.isArray() && schema.getType() == Type.ARRAY) {
            ArrayNode node = (ArrayNode) json;
            ArrayNode newNode = factory.arrayNode();
            Iterator<JsonNode> iterator = node.elements();
            while (iterator.hasNext()) {
                newNode.add(convertFromSimpleRecord(schema.getElementType(), iterator.next(), factory));
            }
            return newNode;
        } else {
            return json;
        }
    }

    private static JsonNode convertToSimpleRecord(Schema schema, JsonNode json, JsonNodeFactory factory)
            throws IOException {
        if (json.isObject() && schema.getType() == Type.RECORD) {
            ObjectNode node = (ObjectNode) json;
            ObjectNode newNode = factory.objectNode();
            for (Field field : schema.getFields()) {
                String fieldName = field.name();
                if (node.has(fieldName)) {
                    JsonNode value = convertToSimpleRecord(field.schema(), node.get(fieldName), factory);
                    if (!value.isNull()) {
                        newNode.set(fieldName, value);
                    }
                }
            }
            return newNode;
        } else if (json.isObject() && schema.getType() == Type.MAP) {
            ObjectNode node = (ObjectNode) json;
            ObjectNode newNode = factory.objectNode();
            Schema valueType = schema.getValueType();
            Iterator<Entry<String, JsonNode>> entries = node.fields();
            while (entries.hasNext()) {
                Entry<String, JsonNode> entry = entries.next();
                JsonNode value = convertToSimpleRecord(valueType, entry.getValue(), factory);
                if (value.isNull()) {
                    newNode.set(entry.getKey(), value);
                }
            }
            return newNode;
        } else if (schema.getType() == Type.UNION) {
            Schema type = getSimpleUnionType(schema);
            if (type == null) {
                if (json.isNull()) {
                    return json;
                } else {
                    ObjectNode node = (ObjectNode) json;
                    Entry<String, JsonNode> entry = node.fields().next();
                    for (Schema unionType : schema.getTypes()) {
                        if (unionType.getFullName().equals(entry.getKey())) {
                            ObjectNode newNode = factory.objectNode();
                            newNode.set(entry.getKey(),
                                    convertToSimpleRecord(unionType, entry.getValue(), factory));
                            return newNode;
                        }
                    }
                    throw new IOException("Unable to get schema for type " + entry.getKey() + " in union");
                }
            } else if (json.isNull()) {
                return json;
            } else {
                return convertToSimpleRecord(type, json.get(type.getFullName()), factory);
            }
        } else if (json.isArray() && schema.getType() == Type.ARRAY) {
            ArrayNode node = (ArrayNode) json;
            ArrayNode newNode = factory.arrayNode();
            Iterator<JsonNode> iterator = node.elements();
            while (iterator.hasNext()) {
                newNode.add(convertToSimpleRecord(schema.getElementType(), iterator.next(), factory));
            }
            return newNode;
        } else {
            return json;
        }
    }
}