com.google.refine.model.medadata.PackageExtension.java Source code

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Here is the source code for com.google.refine.model.medadata.PackageExtension.java

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package com.google.refine.model.medadata;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.exception.ExceptionUtils;
import org.apache.commons.lang3.StringUtils;
import org.everit.json.schema.ValidationException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.frictionlessdata.datapackage.Package;
import io.frictionlessdata.datapackage.exceptions.DataPackageException;

/** 
 * This class contains some methods which is not included in the official "Data Package" repo for now.
 * Some methods can be removed after the official library provide the corresponding function.
 */
public class PackageExtension {
    private final static Logger logger = LoggerFactory.getLogger(PackageExtension.class);

    private static final int JSON_INDENT_FACTOR = 4;

    public static final String JSON_KEY_LAST_UPDATED = "last_updated";
    public static final String JSON_KEY_DESCRIPTION = "description";
    public static final String JSON_KEY_KEYWORKS = "keywords";
    public static final String JSON_KEY_TITLE = "title";
    public static final String JSON_KEY_HOMEPAGE = "homepage";
    public static final String JSON_KEY_IMAGE = "image";
    public static final String JSON_KEY_LICENSE = "license";
    public static final String JSON_KEY_VERSION = "version";

    public static String DATAPACKAGE_TEMPLATE_FILE = "schemas/datapackage-template.json";

    /**
     * Do the package since the final spec for the compression/bundle are not settled yet.
     * https://github.com/frictionlessdata/datapackage-js/issues/93
     * 
     * @param pkg Package 
     * @param dataByteArrayOutputStream  ByteArrayOutputStream
     * @param destOs OutputStream
     * @throws IOException 
     * @throws FileNotFoundException 
     * @see Package#saveZip(String outputFilePath) 
     */
    public static void saveZip(Package pkg, final ByteArrayOutputStream dataByteArrayOutputStream,
            final OutputStream destOs) throws FileNotFoundException, IOException {
        try (ZipOutputStream zos = new ZipOutputStream(destOs)) {
            // json file 
            ZipEntry entry = new ZipEntry(DataPackageMetadata.DEFAULT_FILE_NAME);
            zos.putNextEntry(entry);
            zos.write(pkg.getJson().toString(JSON_INDENT_FACTOR).getBytes());
            zos.closeEntry();
            // default data file to data.csv or given path(can only handle one file because files cannot be restored)
            String path = (String) pkg.getResources().get(0).getPath();
            entry = new ZipEntry(StringUtils.isBlank(path) ? "data.csv" : path);
            zos.putNextEntry(entry);
            zos.write(dataByteArrayOutputStream.toByteArray());
            zos.closeEntry();
        }
    }

    /**
     * To build a Package object from a template file contains empty metadata
     *  
     * @param templateFile
     */
    public static Package buildPackageFromTemplate() {
        try {
            ClassLoader classLoader = PackageExtension.class.getClassLoader();
            File file = new File(classLoader.getResource(DATAPACKAGE_TEMPLATE_FILE).getFile());
            return new Package(FileUtils.readFileToString(file), false);
        } catch (ValidationException e) {
            logger.error("validation failed", ExceptionUtils.getStackTrace(e));
        } catch (DataPackageException e) {
            logger.error("DataPackage Exception", ExceptionUtils.getStackTrace(e));
        } catch (IOException e) {
            logger.error("IOException when build package from template", ExceptionUtils.getStackTrace(e));
        }

        return null;
    }
}