ch.eitchnet.csvrestendpoint.components.CsvDataHandler.java Source code

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Here is the source code for ch.eitchnet.csvrestendpoint.components.CsvDataHandler.java

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/*
 * Copyright 2015 Robert von Burg <eitch@eitchnet.ch>
 * 
 * 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 ch.eitchnet.csvrestendpoint.components;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;

import ch.eitchnet.csvrestendpoint.marshaller.CsvDataMarshaller;
import li.strolch.agent.api.ComponentContainer;
import li.strolch.agent.api.StrolchComponent;
import li.strolch.runtime.configuration.RuntimeConfiguration;

/**
 * @author Robert von Burg <eitch@eitchnet.ch>
 */
public class CsvDataHandler extends StrolchComponent {

    /**
     * @param container
     * @param componentName
     */
    public CsvDataHandler(ComponentContainer container, String componentName) {
        super(container, componentName);
    }

    public List<String> getCsvNames() {

        File csvDataDir = getCsvDataDir();
        if (!csvDataDir.isDirectory()) {
            logger.error("CSV Data Dir is not a directory at " + csvDataDir.getAbsolutePath());
            return Collections.emptyList();
        }

        try (DirectoryStream<Path> directoryStream = Files.newDirectoryStream(csvDataDir.toPath())) {

            List<String> names = new ArrayList<>();

            for (Iterator<Path> iter = directoryStream.iterator(); iter.hasNext();) {
                Path path = iter.next();
                String name = path.toFile().getName();
                if (name.endsWith(".csv"))
                    names.add(name.substring(0, name.length() - 4));
            }

            return names;

        } catch (Exception e) {
            throw new RuntimeException("Failed to read CSV names due to " + e.getMessage());
        }
    }

    public <T> T getCsvData(String name, CsvDataMarshaller<T> marshaller) {

        File csvDataDir = getCsvDataDir();
        if (!csvDataDir.isDirectory()) {
            logger.error("CSV Data Dir is not a directory at " + csvDataDir.getAbsolutePath());
            return null;
        }

        String csvFileName = name + ".csv";
        File csvFile = new File(csvDataDir, csvFileName);
        if (!csvFile.isFile()) {
            logger.error("CSV File is not a file at " + csvFile.getAbsolutePath());
            return null;
        }

        try (Reader reader = new InputStreamReader(new FileInputStream(csvFile), marshaller.getCharset())) {

            CSVFormat csvFormat = marshaller.getCsvFormat();
            CSVParser csvParser = csvFormat.parse(reader);
            return marshaller.marshall(csvParser);

        } catch (IOException e) {
            logger.error(e.getMessage(), e);
            return null;
        }
    }

    private File getCsvDataDir() {
        RuntimeConfiguration runtimeConfiguration = getConfiguration().getRuntimeConfiguration();
        String context = CsvDataHandler.class.getSimpleName();
        return runtimeConfiguration.getDataDir(context, "csv", false);
    }
}