org.apache.druid.java.util.common.parsers.JSONToLowerParser.java Source code

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/*
 * 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 org.apache.druid.java.util.common.parsers;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Function;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import org.apache.druid.java.util.common.StringUtils;

import java.nio.charset.CharsetEncoder;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * TODO:
 * There is a lot of code copy and pasted from JSONParser. JSONParser needs to be rewritten
 * to actually take a map transformer instead of what it is doing now. For the purposes of moving forward in 0.7.0,
 * I am going to have a different parser to lower case data from JSON. This code needs to be removed the next time
 * we touch java-util.
 */
@Deprecated
public class JSONToLowerParser implements Parser<String, Object> {
    private static final Function<JsonNode, Object> valueFunction = new Function<JsonNode, Object>() {
        @Override
        public Object apply(JsonNode node) {
            if (node == null || node.isMissingNode() || node.isNull()) {
                return null;
            }
            if (node.isIntegralNumber()) {
                if (node.canConvertToLong()) {
                    return node.asLong();
                } else {
                    return node.asDouble();
                }
            }
            if (node.isFloatingPointNumber()) {
                return node.asDouble();
            }
            final String s = node.asText();
            final CharsetEncoder enc = StandardCharsets.UTF_8.newEncoder();
            if (s != null && !enc.canEncode(s)) {
                // Some whacky characters are in this string (e.g. \uD900). These are problematic because they are decodeable
                // by new String(...) but will not encode into the same character. This dance here will replace these
                // characters with something more sane.
                return StringUtils.fromUtf8(StringUtils.toUtf8(s));
            } else {
                return s;
            }
        }
    };

    private final ObjectMapper objectMapper;
    private final Set<String> exclude;

    private ArrayList<String> fieldNames;

    public JSONToLowerParser(ObjectMapper objectMapper, Iterable<String> fieldNames, Iterable<String> exclude) {
        this.objectMapper = objectMapper;
        if (fieldNames != null) {
            setFieldNames(fieldNames);
        }
        this.exclude = exclude != null ? Sets.newHashSet(Iterables.transform(exclude, StringUtils::toLowerCase))
                : Sets.newHashSet();
    }

    @Override
    public List<String> getFieldNames() {
        return fieldNames;
    }

    @Override
    public void setFieldNames(Iterable<String> fieldNames) {
        ParserUtils.validateFields(fieldNames);
        this.fieldNames = Lists.newArrayList(fieldNames);
    }

    @Override
    public Map<String, Object> parseToMap(String input) {
        try {
            Map<String, Object> map = new LinkedHashMap<>();
            JsonNode root = objectMapper.readTree(input);

            Iterator<String> keysIter = (fieldNames == null ? root.fieldNames() : fieldNames.iterator());

            while (keysIter.hasNext()) {
                String key = keysIter.next();

                if (exclude.contains(StringUtils.toLowerCase(key))) {
                    continue;
                }

                JsonNode node = root.path(key);

                if (node.isArray()) {
                    final List<Object> nodeValue = Lists.newArrayListWithExpectedSize(node.size());
                    for (final JsonNode subnode : node) {
                        final Object subnodeValue = valueFunction.apply(subnode);
                        if (subnodeValue != null) {
                            nodeValue.add(subnodeValue);
                        }
                    }
                    map.put(StringUtils.toLowerCase(key), nodeValue); // difference from JSONParser parse()
                } else {
                    final Object nodeValue = valueFunction.apply(node);
                    if (nodeValue != null) {
                        map.put(StringUtils.toLowerCase(key), nodeValue); // difference from JSONParser parse()
                    }
                }
            }
            return map;
        } catch (Exception e) {
            throw new ParseException(e, "Unable to parse row [%s]", input);
        }
    }
}