JacksonUtils.java

package gov.nasa.jpl.mbee.mdk.json;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.NullNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import gov.nasa.jpl.mbee.mdk.util.MDUtils;
import gov.nasa.jpl.mbee.mdk.options.MDKOptionsGroup;
import org.apache.commons.lang.math.NumberUtils;

import java.io.IOException;
import java.util.LinkedList;
import java.util.function.Function;

/**
 * Created by igomes on 9/26/16.
 */
public class JacksonUtils {
    private static ObjectMapper OBJECT_MAPPER_INSTANCE;
    private static JsonFactory JSON_FACTORY_INSTANCE;

    public static ObjectMapper getObjectMapper() {
        if (OBJECT_MAPPER_INSTANCE == null) {
            OBJECT_MAPPER_INSTANCE = new ObjectMapper();
            if (MDUtils.isDeveloperMode()) {
                OBJECT_MAPPER_INSTANCE.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS, true);
                if (MDKOptionsGroup.getMDKOptions().isLogJson()) {
                    OBJECT_MAPPER_INSTANCE.enable(SerializationFeature.INDENT_OUTPUT);
                }
            }
        }
        return OBJECT_MAPPER_INSTANCE;
    }

    public static JsonFactory getJsonFactory() {
        if (JSON_FACTORY_INSTANCE == null) {
            JSON_FACTORY_INSTANCE = new JsonFactory();
            JSON_FACTORY_INSTANCE.setCodec(JacksonUtils.getObjectMapper());
        }
        return JSON_FACTORY_INSTANCE;
    }

    public static JsonNode getAtPath(JsonNode json, String path) {
        if (path.startsWith("/")) {
            path = path.substring(1);
        }
        for (String key : path.split("/")) {
            key = key.replace("~0", "~").replace("~1", "/");
            if (json.isArray()) {
                if (!NumberUtils.isDigits(key)) {
                    return NullNode.getInstance();
                }
                int index = Integer.parseInt(key);
                if (index >= json.size()) {
                    return NullNode.getInstance();
                }
                json = json.get(index);
            }
            else {
                if (!json.has(key)) {
                    return NullNode.getInstance();
                }
                json = json.get(key);
            }
        }
        return json;
    }

    public static <R> R getAtPath(JsonNode json, String path, Function<JsonNode, R> function) {
        return function.apply(getAtPath(json, path));
    }

    @Deprecated
    public static void put(ObjectNode objectNode, String fieldName, Object object) {
        if (object == null) {
            objectNode.putNull(fieldName);
        }
        else if (object instanceof JsonNode) {
            objectNode.set(fieldName, (JsonNode) object);
        }
        else if (object instanceof String) {
            objectNode.put(fieldName, (String) object);
        }
        else if (object instanceof Boolean) {
            objectNode.put(fieldName, (Boolean) object);
        }
        else if (object instanceof Integer) {
            objectNode.put(fieldName, (Integer) object);
        }
        else if (object instanceof Double) {
            objectNode.put(fieldName, (Double) object);
        }
        else if (object instanceof Long) {
            objectNode.put(fieldName, (Long) object);
        }
        else if (object instanceof Short) {
            objectNode.put(fieldName, (Short) object);
        }
        else if (object instanceof Float) {
            objectNode.put(fieldName, (Float) object);
        }
        else if (object instanceof byte[]) {
            objectNode.put(fieldName, (byte[]) object);
        }
    }

    public static ObjectNode parseJsonObject(JsonParser jsonParser) throws IOException {
        JsonToken current = (jsonParser.getCurrentToken() == null ? jsonParser.nextToken() : jsonParser.getCurrentToken());
        if (current != JsonToken.START_OBJECT) {
            throw new IOException("Unable to build object from JSON parser.");
        }
        ObjectNode objectNode = getObjectMapper().readTree(jsonParser);
        return objectNode;
    }

    public static ArrayNode parseJsonArray(JsonParser jsonParser, ArrayNode arrayNode) throws IOException {
        JsonToken current = (jsonParser.getCurrentToken() == null ? jsonParser.nextToken() : jsonParser.getCurrentToken());
        if (current != JsonToken.START_ARRAY) {
            throw new IOException("Unable to build array from JSON parser.");
        }
        current = jsonParser.nextToken();
        if (arrayNode == null) {
            arrayNode = getObjectMapper().createArrayNode();
        }
        while (current != JsonToken.END_ARRAY) {
            if (jsonParser.getCurrentToken() == JsonToken.START_OBJECT) {
                arrayNode.add(parseJsonObject(jsonParser));
            }
            else if (jsonParser.getCurrentToken() == JsonToken.START_ARRAY) {
                arrayNode.add(parseJsonArray(jsonParser, null));
                if (jsonParser.getCurrentToken() != JsonToken.END_ARRAY) {
                    throw new IOException("Missed Array End.");
                }
            }
            else {
                arrayNode.add(jsonParser.getText());
            }
            current = jsonParser.nextToken();
        }
        return arrayNode;
    }

    public static LinkedList<ObjectNode> parseJsonResponseToObjectList(JsonParser jsonParser, ObjectNode messages) throws IOException {
        JsonToken current = (jsonParser.getCurrentToken() == null ? jsonParser.nextToken() : jsonParser.getCurrentToken());
        if (current != JsonToken.START_OBJECT) {
            throw new IOException("Unable to build object from JSON parser.");
        }
        LinkedList<ObjectNode> results = new LinkedList<>();
        while (current != JsonToken.END_OBJECT) {
            if (jsonParser.getCurrentName() == null) {
                current = jsonParser.nextToken();
                continue;
            }
            String keyName = jsonParser.getCurrentName();
            switch (keyName) {
                case "orgs":
                case "projects":
                case "refs":
                case "elements": {
                    jsonParser.nextToken();
                    current = jsonParser.nextToken();
                    while (current != JsonToken.END_ARRAY) {
                        if (current == JsonToken.START_OBJECT) {
                            results.add(parseJsonObject(jsonParser));
                        }
                        else {
                            // consume and ignore
                            current = jsonParser.nextToken();
                        }
                        current = jsonParser.getCurrentToken();
                    }
                    break;
                }
                default: {
                    current = jsonParser.nextToken();
                    if (messages != null) {
                        if (current == JsonToken.START_ARRAY) {
                            ArrayNode arraynode = messages.putArray(keyName);
                            JacksonUtils.parseJsonArray(jsonParser, arraynode);
                        }
                        else {
                            messages.put(keyName, jsonParser.getText());
                        }
                    }
                }
            }
            current = jsonParser.nextToken();
        }
        return results;
    }

}