databuild/examples/basic_graph/SumExecute.java

package com.databuild.examples.basic_graph;

import static com.databuild.examples.basic_graph.GenerateExecute.BASE_PATH;

public class SumExecute {
    public static void main(String[] args) {
        if (args.length < 1) {
            System.err.println("Error: Partition ref (output path) is required");
            System.exit(1);
        }

        // Get output ref from env var OUTPUT_REF
        String outputRef = System.getenv("OUTPUT_REF");

        // For each arg, load it from the file system and add it to the sum
        int sum = 0;
        for (String partitionRef : args) {
            try {
                String path = partitionRef;
                int partitionValue = Integer.parseInt(new String(java.nio.file.Files.readAllBytes(java.nio.file.Paths.get(path))));
                System.out.println("Summing partition " + partitionRef + " with value " + partitionValue);
                sum += partitionValue;
            } catch (Exception e) {
                System.err.println("Error: Failed to read partition " + partitionRef + ": " + e.getMessage());
                e.printStackTrace();
            }
        }
        System.out.println("Sum of " + args.length + " partitions: " + sum);
        // Write the sum to the output file
        String outPath = outputRef;
        System.out.println("Writing sum " + sum + " to " + outPath);

        java.io.File parent = new java.io.File(outPath).getParentFile();
        if (parent != null) {
            parent.mkdirs();
        }

        try (java.io.FileWriter writer = new java.io.FileWriter(outPath)) {
            writer.write(String.valueOf(sum));
        } catch (Exception e) {
            System.err.println("Error: Failed to write sum to " + outputRef + ": " + e.getMessage());
        }
    }
}