com.facebook.data.types.DatumUtils.java Source code

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Here is the source code for com.facebook.data.types.DatumUtils.java

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/*
 * Copyright (C) 2012 Facebook, Inc.
 *
 * Licensed 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 com.facebook.data.types;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

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

/**
 * utility methods for operating on Datums
 */
public class DatumUtils {

    /**
     * recursively converts the mapDatum into a valid JSONObject
     *
     * @param mapDatum
     * @return JSONObject
     */
    public static JSONObject buildJSON(MapDatum mapDatum) {
        JSONObject jsonObject = new JSONObject();
        Map<Datum, Datum> map = mapDatum.getMap();

        try {
            for (Map.Entry<Datum, Datum> entry : map.entrySet()) {
                String key = entry.getKey().asString();
                DatumType valueDatumType = entry.getValue().getType();

                if (valueDatumType == DatumType.LIST) {
                    jsonObject.put(key, buildJSON((ListDatum) entry.getValue()));
                } else if (valueDatumType == DatumType.MAP) {
                    jsonObject.put(key, buildJSON((MapDatum) entry.getValue()));
                } else {
                    jsonObject.put(key, entry.getValue().asRaw());
                }
            }

            return jsonObject;
        } catch (JSONException e) {
            throw new RuntimeException("error converting json object to string", e);
        }

    }

    /**
     * recursively converts contained Datums into a valid JSONArray.
     *
     * @param listDatum
     * @return JSONArray
     */
    public static JSONArray buildJSON(ListDatum listDatum) {
        JSONArray jsonArray = new JSONArray();
        List<Datum> datumList = listDatum.asList();

        try {
            int i = 0;

            for (Datum datum : datumList) {
                DatumType datumType = datum.getType();

                if (datumType == DatumType.LIST) {
                    jsonArray.put(i, buildJSON((ListDatum) datum));
                } else if (datumType == DatumType.MAP) {
                    jsonArray.put(i, buildJSON((MapDatum) datum));
                } else {
                    jsonArray.put(i, datum.asRaw());
                }

                i++;
            }

            return jsonArray;
        } catch (JSONException e) {
            throw new RuntimeException("some element did not conform to JSON format: " + datumList, e);
        }
    }

    /**
     * {impressionTimestamp, adId}
     * <p/>
     * and creates JSON with
     * <pre>
     *
     *  {
     *    keyNames[0] : rawTuple[0],
     *    keyNames[1] : rawTuple[1],
     *    ...
     *    keyNames[n] : rawTuple[n],
     *  }
     *  </pre>
     *
     * @param rawTuple - impressionTimestamp, adId
     * @return
     */
    public static MapDatum toMapDatum(LongDatum[] rawTuple, StringDatum[] keyNames) {
        assert rawTuple.length == keyNames.length;

        Map<Datum, Datum> datumMap = new HashMap<Datum, Datum>(rawTuple.length);

        for (int i = 0; i < rawTuple.length; i++) {
            datumMap.put(keyNames[i], rawTuple[i]);
        }

        return new MapDatum(datumMap);

    }

    /**
     * @param value    byte, short, int, long to translate big-endian to an array
     * @param numBytes 1 = byte, 2 short, 4 = int, 8 = long.  or try 5 for the heck of it.
     * @return
     */
    public static byte[] toBytes(long value, int numBytes) {
        byte[] bytes = new byte[numBytes];

        for (int i = numBytes - 1; i > 0; i--) {
            bytes[i] = (byte) value;
            value >>>= 8;
        }

        bytes[0] = (byte) value;

        return bytes;
    }
}