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

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Here is the source code for com.metamx.common.parsers.CSVParser.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.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.base.Splitter;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.metamx.common.collect.Utils;
import com.metamx.common.logger.Logger;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

public class CSVParser implements Parser<String, Object> {
    private static final Logger log = new Logger(CSVParser.class);

    private final String listDelimiter;
    private final Splitter listSplitter;
    private final Function<String, Object> valueFunction;

    private final au.com.bytecode.opencsv.CSVParser parser = new au.com.bytecode.opencsv.CSVParser();

    private ArrayList<String> fieldNames = null;

    public CSVParser(final Optional<String> listDelimiter) {
        this.listDelimiter = listDelimiter.isPresent() ? listDelimiter.get() : Parsers.DEFAULT_LIST_DELIMITER;
        this.listSplitter = Splitter.on(this.listDelimiter);
        this.valueFunction = new Function<String, Object>() {
            @Override
            public Object apply(String input) {
                if (input.contains(CSVParser.this.listDelimiter)) {
                    return Lists.newArrayList(
                            Iterables.transform(listSplitter.split(input), ParserUtils.nullEmptyStringFunction));
                } else {
                    return ParserUtils.nullEmptyStringFunction.apply(input);
                }
            }
        };
    }

    public CSVParser(final Optional<String> listDelimiter, final Iterable<String> fieldNames) {
        this(listDelimiter);

        setFieldNames(fieldNames);
    }

    public CSVParser(final Optional<String> listDelimiter, final String header) {
        this(listDelimiter);

        setFieldNames(header);
    }

    public String getListDelimiter() {
        return listDelimiter;
    }

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

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

    public void setFieldNames(final String header) {
        try {
            setFieldNames(Arrays.asList(parser.parseLine(header)));
        } catch (Exception e) {
            throw new ParseException(e, "Unable to parse header [%s]", header);
        }
    }

    @Override
    public Map<String, Object> parse(final String input) {
        try {
            String[] values = parser.parseLine(input);

            if (fieldNames == null) {
                setFieldNames(ParserUtils.generateFieldNames(values.length));
            }

            return Utils.zipMapPartial(fieldNames, Iterables.transform(Lists.newArrayList(values), valueFunction));
        } catch (Exception e) {
            throw new ParseException(e, "Unable to parse row [%s]", input);
        }
    }
}