com.metamx.common.parsers.JSONParser.java Source code

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Here is the source code for com.metamx.common.parsers.JSONParser.java

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/*
 * Copyright 2011,2012 Metamarkets Group 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.metamx.common.parsers;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

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

public class JSONParser implements Parser<String, Object> {
    public 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 = Charsets.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 new String(s.getBytes(Charsets.UTF_8), Charsets.UTF_8);
            } else {
                return s;
            }
        }
    };

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

    public JSONParser() {
        this(new ObjectMapper(), null, null);
    }

    @Deprecated
    public JSONParser(Iterable<String> fieldNames) {
        this(new ObjectMapper(), fieldNames, null);
    }

    public JSONParser(ObjectMapper objectMapper, Iterable<String> fieldNames) {
        this(objectMapper, fieldNames, null);
    }

    public JSONParser(ObjectMapper objectMapper, Iterable<String> fieldNames, Iterable<String> exclude) {
        this.objectMapper = objectMapper;
        if (fieldNames != null) {
            setFieldNames(fieldNames);
        }
        this.exclude = exclude != null ? Sets.newHashSet(exclude) : Sets.<String>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> parse(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(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(key, nodeValue);
                } else {
                    final Object nodeValue = valueFunction.apply(node);
                    if (nodeValue != null) {
                        map.put(key, nodeValue);
                    }
                }
            }
            return map;
        } catch (Exception e) {
            throw new ParseException(e, "Unable to parse row [%s]", input);
        }
    }
}