SmileToJson.java

package com.tersesystems.buffer.serde;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.dataformat.smile.SmileFactory;
import com.fasterxml.jackson.dataformat.smile.SmileParser;

import java.io.ByteArrayOutputStream;
import java.util.function.Function;

import static com.fasterxml.jackson.dataformat.smile.SmileGenerator.Feature.CHECK_SHARED_NAMES;
import static com.fasterxml.jackson.dataformat.smile.SmileGenerator.Feature.CHECK_SHARED_STRING_VALUES;

/**
 * This is used for converting SMILE back to JSON in the dump format.
 */
public class SmileToJson implements Function<byte[], byte[]> {
    private static SmileFactory smileFactory = new SmileFactory();
    private static final JsonFactory jsonFactory = new JsonFactory();

    static {
        smileFactory = smileFactory.disable(CHECK_SHARED_NAMES).disable(CHECK_SHARED_STRING_VALUES);
    }

    private SmileToJson() {
    }

    public static SmileToJson instance() {
        return SingletonHolder.instance;
    }

    private final static class SingletonHolder {
        private final static SmileToJson instance = new SmileToJson();
    }

    public byte[] apply(byte[] bytes) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try (
            SmileParser sp = smileFactory.createParser(bytes);
            JsonGenerator jg = jsonFactory.createGenerator(bos)
        ) {
            while (sp.nextToken() != null) {
                jg.copyCurrentEvent(sp);
            }
            return bos.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}