GenerateCsv.java

amitsen01ei

Feb 4th, 2024

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import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.StandardOpenOption;
import java.time.Duration;
import java.time.Instant;
import java.util.UUID;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import static fi.CheckedConsumer.tryConsume;
import static common.IO.*;
final String outputPath = "/Users/amit.sen/Desktop/uuids-medium.csv";
void main() throws Throwable {
delete(outputPath);
var start = Instant.now();
generateUuidCsv(10000000, 5, outputPath);
println(STR."Time Taken \{Duration.between(start, Instant.now()).getSeconds()} seconds.");
var fileSizeInMB = new File(outputPath).length() / (1000.0D * 1000.0D);
var fileSizeInGB = fileSizeInMB / 1000.0D;
println(STR."Generated File Size \{fileSizeInGB < 0.0D ? STR."\{fileSizeInMB} MB" : STR."\{fileSizeInGB} GB"}");
}
boolean delete(String path) {
return new File(path).delete();
}
File generateUuidCsv(int rows, int itemPerRow, String path) throws IOException {
final var outputPath = new File(path);
final var batchSize = 10000;
if (outputPath.createNewFile()) {
println(STR."\{path.substring(path.lastIndexOf("/") + 1)} is created.");
} else {
println(STR."\{path.substring(path.lastIndexOf("/") + 1)} already exists. Skipping creation.");
}
final var iterations = rows / batchSize;
IntStream.rangeClosed(1, iterations == 0 ? rows : iterations)
.parallel()
.mapToObj(_ -> IntStream.rangeClosed(1, rows < batchSize ? 1 : batchSize)
.mapToObj(_ -> createRow(itemPerRow)).collect(Collectors.joining())
).forEach(tryConsume(content -> Files.write(outputPath.toPath(),
content.getBytes(),
StandardOpenOption.APPEND)
)
);
return outputPath;
}
String createRow(int item) {
return STR."\{IntStream.rangeClosed(1, item)
.mapToObj(_ -> UUID.randomUUID().toString())
.collect(Collectors.joining(","))}\n";
}

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