/
Downloader.java
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/
Downloader.java
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package com.exasol.bucketfs.client;
import static com.exasol.bucketfs.url.BucketFsLocation.asDirectory;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;
import com.exasol.bucketfs.BucketAccessException;
import com.exasol.bucketfs.ReadOnlyBucket;
import com.exasol.bucketfs.client.UseCaseDetector.RecurseOption;
import com.exasol.bucketfs.client.UseCaseDetector.UseCase;
import com.exasol.bucketfs.url.BucketFsLocation;
import com.exasol.bucketfs.url.BucketFsUrl;
import com.exasol.errorreporting.ExaError;
public class Downloader {
private static final Logger LOGGER = Logger.getLogger(Downloader.class.getName());
private final BucketFsClient parent;
private final ReadOnlyBucket bucket;
private final BucketFsUrl source;
private final Path destination;
public Downloader(final BucketFsClient parent, final ReadOnlyBucket bucket, final BucketFsUrl source,
final Path destination) {
this.parent = parent;
this.bucket = bucket;
this.source = source;
this.destination = destination;
}
public void download() throws BucketAccessException, IOException {
final BucketFsLocation location = BucketFsLocation.from(this.bucket, this.source.getPathInBucket());
final RecurseOption recurseOption = RecurseOption.from(this.parent::recursiveOption, this.parent::isRecursive);
final UseCase usecase = new UseCaseDetector(this.source, this.destination, recurseOption).detect(location);
final Path dest = destinationWithFilename(location);
if (usecase == UseCase.DIRECTORY) {
final String prefix = asDirectory(this.source.getPathInBucket());
for (final String spec : getFilesForDownload()) {
final Path file = dest.resolve(spec);
Files.createDirectories(file.getParent());
LOGGER.finer(() -> "Downloading " + this.source + spec + " to " + file);
this.bucket.downloadFile(prefix + spec, file);
}
} else {
this.bucket.downloadFile(this.source.getPathInBucket(), dest);
}
}
/**
* Potentially append filename from path in bucket to destination path.
*
* @param location
* @return destination incl. filename
*/
private Path destinationWithFilename(final BucketFsLocation location) {
return Files.isDirectory(this.destination) //
? this.destination.resolve(location.getLastComponent())
: this.destination;
}
// [impl->dsn~copy-ambigue-entrie-on-lower-level~1]
private List<String> getFilesForDownload() throws BucketAccessException {
final List<String> list = this.bucket.listContentsRecursively(this.source.getPathInBucket());
final List<String> result = new ArrayList<>();
final int n = list.size();
for (int i = 0; i < n; i++) {
final String current = list.get(i);
final String next = (i < (n - 1)) ? list.get(i + 1) : null;
if ((next != null) && next.startsWith(current)) {
this.parent.printWarning(ExaError.messageBuilder("W-BFSC-14") //
.message("Skipping ambigue file {{file}} as BucketFS contains directory with identical name.", //
asDirectory(this.source.getPathInBucket()) + current) //
.toString());
} else {
result.add(current);
}
}
return result;
}
}