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

Introduction

Here is the source code for org.apache.druid.java.util.common.parsers.ParserUtils.java

Source

/*
 * 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.google.common.base.Function;
import com.google.common.base.Splitter;
import com.google.common.collect.Sets;
import org.apache.druid.common.config.NullHandling;
import org.apache.druid.java.util.common.StringUtils;
import org.joda.time.DateTimeZone;

import javax.annotation.Nullable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

public class ParserUtils {
    private static final String DEFAULT_COLUMN_NAME_PREFIX = "column_";

    private static final Map<String, DateTimeZone> TIMEZONE_LOOKUP = new HashMap<>();

    static {
        for (String tz : TimeZone.getAvailableIDs()) {
            try {
                TIMEZONE_LOOKUP.put(tz, DateTimeZone.forTimeZone(TimeZone.getTimeZone(tz)));
            } catch (IllegalArgumentException e) {
                // Ignore certain date time zone ids like SystemV/AST4. More here https://confluence.atlassian.com/confkb/the-datetime-zone-id-is-not-recognised-167183146.html
            }
        }
    }

    public static Function<String, Object> getMultiValueFunction(final String listDelimiter,
            final Splitter listSplitter) {
        return (input) -> {
            if (input != null && input.contains(listDelimiter)) {
                return StreamSupport.stream(listSplitter.split(input).spliterator(), false)
                        .map(NullHandling::emptyToNullIfNeeded).collect(Collectors.toList());
            } else {
                return NullHandling.emptyToNullIfNeeded(input);
            }
        };
    }

    public static ArrayList<String> generateFieldNames(int length) {
        final ArrayList<String> names = new ArrayList<>(length);
        for (int i = 0; i < length; ++i) {
            names.add(getDefaultColumnName(i));
        }
        return names;
    }

    public static Set<String> findDuplicates(Iterable<String> fieldNames) {
        Set<String> duplicates = Sets.newHashSet();
        Set<String> uniqueNames = Sets.newHashSet();

        for (String fieldName : fieldNames) {
            String next = StringUtils.toLowerCase(fieldName);
            if (uniqueNames.contains(next)) {
                duplicates.add(next);
            }
            uniqueNames.add(next);
        }

        return duplicates;
    }

    public static void validateFields(Iterable<String> fieldNames) {
        Set<String> duplicates = findDuplicates(fieldNames);
        if (!duplicates.isEmpty()) {
            throw new ParseException("Duplicate column entries found : %s", duplicates.toString());
        }
    }

    public static String stripQuotes(String input) {
        input = input.trim();
        if (input.charAt(0) == '\"' && input.charAt(input.length() - 1) == '\"') {
            input = input.substring(1, input.length() - 1).trim();
        }
        return input;
    }

    @Nullable
    public static DateTimeZone getDateTimeZone(String timeZone) {
        return TIMEZONE_LOOKUP.get(timeZone);
    }

    /**
     * Return a function to generate default column names.
     * Note that the postfix for default column names starts from 1.
     *
     * @return column name generating function
     */
    public static String getDefaultColumnName(int ordinal) {
        return DEFAULT_COLUMN_NAME_PREFIX + (ordinal + 1);
    }
}