src/main/java/de/ids_mannheim/korap/response/MetaField.java

package de.ids_mannheim.korap.response;

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

import java.util.*;

import org.apache.lucene.index.*;

/**
 * Class representing a meta field.
 */
public class MetaField {

	// Mapper for JSON serialization
    ObjectMapper mapper = new ObjectMapper();

	public String type;
	public String key;
	public List<String> values = new ArrayList<>();

    public MetaField (String key) {
		this.key = key;
	};

    public MetaField (String key, String type) {
        this.key = key;
        this.type = type;
	};

    public MetaField (String key, String type, String value) {
        this.key = key;
        this.type = type;
        this.values.add(value);
    };

    /**
     * Add value to meta field.
     */
    public MetaField addValue (String value) {
        this.values.add(value);
        return this;
    };

    
	/**
	 * Create JsonNode
	 */
	public JsonNode toJsonNode () {
        ObjectNode json = mapper.createObjectNode();
		json.put("@type", "koral:field");
        json.put("key", this.key);

        if (this.type == null)
            return json;
            
        json.put("type", this.type);

		// Value is numerical
		if (this.type.equals("type:integer")) {

			// Value is a list
			if (this.values.size() > 1) {
				ArrayNode list = json.putArray("value");

				Iterator vIter = this.values.iterator();
				while (vIter.hasNext()) {
					list.add((int) Integer.parseInt((String) vIter.next()));
				};
			}

			// Value is a single
			else {
				json.put("value", Integer.parseInt(this.values.get(0)));
			};
		}

        
		// Value is textual or keywords
		else {
            // Value is a list
			if (this.values.size() > 1) {
				ArrayNode list = json.putArray("value");

				Iterator vIter = this.values.iterator();
				while (vIter.hasNext()) {
					list.add((String) vIter.next());
				};
			}

			// Value is a single
			else if (this.values.size() > 0) {
				json.put("value", this.values.get(0));
			};
		};

		return (JsonNode) json;
	};
};