org.projectnessie.versioned.transfer.files.FileExporter Maven / Gradle / Ivy
/*
* Copyright (C) 2022 Dremio
*
* 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 org.projectnessie.versioned.transfer.files;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static java.nio.file.Files.createDirectories;
import static java.nio.file.Files.exists;
import static java.nio.file.Files.isDirectory;
import static java.nio.file.Files.newOutputStream;
import jakarta.annotation.Nonnull;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;
import org.immutables.value.Value;
/** Nessie exporter that writes to individual files into an empty target directory. */
@Value.Immutable
public abstract class FileExporter implements ExportFileSupplier {
public static Builder builder() {
return ImmutableFileExporter.builder();
}
public interface Builder {
Builder targetDirectory(Path targetDirectory);
FileExporter build();
}
abstract Path targetDirectory();
@Override
@Nonnull
public Path getTargetPath() {
return targetDirectory();
}
@Override
public void preValidate() throws IOException {
if (isDirectory(targetDirectory())) {
try (Stream listing = Files.list(targetDirectory())) {
checkState(
listing.findAny().isEmpty(),
"Target directory %s must be empty, but is not",
targetDirectory());
}
} else {
createDirectories(targetDirectory());
}
}
@Override
@Nonnull
public OutputStream newFileOutput(@Nonnull String fileName) throws IOException {
checkArgument(
fileName.indexOf('/') == -1 && fileName.indexOf('\\') == -1, "Directories not supported");
Path f = Paths.get(fileName);
checkArgument(!fileName.isEmpty(), "Invalid file name argument");
f = targetDirectory().resolve(f);
checkState(!exists(f), "File %s already exists", fileName);
return newOutputStream(f);
}
@Override
public void close() {}
}