java-topology/defects/phoenix/unit/PhoenixTest.java

package unit;

import java.util.*;

/**
 * PhoenixTest — CWE-407 benchmark for Phoenix channel event_intercepts (phoenix-0001)
 * and router scope pipes (phoenix-0002).
 *
 * Models the Elixir data structures in Java:
 *   - Slow: List<String> for event_intercepts / pipes  (List.contains = O(n))
 *   - Fast: HashSet<String> for event_intercepts / pipes (HashSet.contains = O(1))
 *
 * phoenix-0001: dispatch() iterates all subscribers checking event in event_intercepts.
 *   Slow: O(subscribers * intercepts) list scan per broadcast.
 *   Fast: O(subscribers) with HashSet.contains(event).
 *
 * phoenix-0002: pipe_through() checks for duplicate pipes.
 *   Slow: O(new_pipes * existing_pipes) nested list scans.
 *   Fast: O(new_pipes) with HashSet.contains.
 */
public class PhoenixTest {

    static void bench(String label, Runnable slow, Runnable fast, long sOps, long fOps) {
        // warmup
        slow.run();
        fast.run();
        long t0 = System.nanoTime();
        slow.run();
        long sMs = (System.nanoTime() - t0) / 1_000_000;
        long t1 = System.nanoTime();
        fast.run();
        long fMs = (System.nanoTime() - t1) / 1_000_000;
        double r = fMs > 0 ? (double) sMs / fMs : 0;
        System.out.printf("  %-52s  slow:%4dms (%,d ops)  fast:%4dms (%,d ops)  speedup:%.1fx%n",
                label, sMs, sOps, fMs, fOps, r);
    }

    // -----------------------------------------------------------------------
    // phoenix-0001: channel dispatch — event in event_intercepts
    // Models: N subscribers each holding a List<String> of K intercepted events.
    // Per broadcast: check event membership for all subscribers.
    // -----------------------------------------------------------------------

    static long dispatchSlow(List<String[]> subscribers, String event, int broadcastCount) {
        long matches = 0;
        for (int b = 0; b < broadcastCount; b++) {
            for (String[] intercepts : subscribers) {
                // Elixir: event in event_intercepts (List.member? — O(k))
                for (String e : intercepts) {
                    if (e.equals(event)) {
                        matches++;
                        break;
                    }
                }
            }
        }
        return matches;
    }

    static long dispatchFast(List<Set<String>> subscriberSets, String event, int broadcastCount) {
        long matches = 0;
        for (int b = 0; b < broadcastCount; b++) {
            for (Set<String> intercepts : subscriberSets) {
                // MapSet.member? — O(1)
                if (intercepts.contains(event)) {
                    matches++;
                }
            }
        }
        return matches;
    }

    // -----------------------------------------------------------------------
    // phoenix-0002: pipe_through duplicate check
    // Models: accumulating P pipes one-by-one, checking for duplicates each time.
    // -----------------------------------------------------------------------

    static int pipeAccumulateSlow(int totalPipes) {
        // Elixir: pipes is a List — duplicate check via Enum.find(&1 in pipes)
        List<String> pipes = new ArrayList<>();
        int duplicatesFound = 0;
        for (int i = 0; i < totalPipes; i++) {
            String newPipe = "pipeline_" + i;
            // O(n) scan for duplicate
            boolean isDuplicate = false;
            for (String p : pipes) {
                if (p.equals(newPipe)) {
                    isDuplicate = true;
                    break;
                }
            }
            if (!isDuplicate) {
                // O(n) append via list concat simulation
                pipes.add(newPipe);
            } else {
                duplicatesFound++;
            }
        }
        return duplicatesFound;
    }

    static int pipeAccumulateFast(int totalPipes) {
        // Elixir fix: pipes is a MapSet — duplicate check via MapSet.member?
        Set<String> pipes = new HashSet<>();
        int duplicatesFound = 0;
        for (int i = 0; i < totalPipes; i++) {
            String newPipe = "pipeline_" + i;
            // O(1) membership check
            if (pipes.contains(newPipe)) {
                duplicatesFound++;
            } else {
                pipes.add(newPipe); // O(1) add
            }
        }
        return duplicatesFound;
    }

    public static void main(String[] args) {
        System.out.println("Phoenix CWE-407 Benchmarks");
        System.out.println("==========================");
        System.out.println();

        // --- phoenix-0001: channel dispatch ---
        System.out.println("phoenix-0001: channel dispatch event_intercepts (N=10000 subscribers, K=10 intercepts, 200 broadcasts)");
        int N_SUBSCRIBERS = 10_000;
        int K_INTERCEPTS = 10;
        int BROADCASTS = 200;

        // Build slow: each subscriber holds a List<String> of K event names
        List<String[]> slowSubscribers = new ArrayList<>(N_SUBSCRIBERS);
        List<Set<String>> fastSubscribers = new ArrayList<>(N_SUBSCRIBERS);
        String[] interceptNames = new String[K_INTERCEPTS];
        for (int k = 0; k < K_INTERCEPTS; k++) {
            interceptNames[k] = "event_" + k;
        }
        for (int i = 0; i < N_SUBSCRIBERS; i++) {
            slowSubscribers.add(interceptNames.clone());
            fastSubscribers.add(new HashSet<>(Arrays.asList(interceptNames)));
        }
        // Target event is the last one (worst case for list scan)
        String targetEvent = "event_" + (K_INTERCEPTS - 1);

        long sOps = (long) N_SUBSCRIBERS * BROADCASTS;
        long fOps = sOps;

        bench(
            "dispatch: event in List<intercepts> vs HashSet<intercepts>",
            () -> dispatchSlow(slowSubscribers, targetEvent, BROADCASTS),
            () -> dispatchFast(fastSubscribers, targetEvent, BROADCASTS),
            sOps, fOps
        );

        // Vary K — show the O(K) scaling
        System.out.println();
        System.out.println("phoenix-0001: vary K (intercepts per subscriber), N=5000, 100 broadcasts");
        int[] kValues = {1, 5, 10, 20, 50};
        for (int K : kValues) {
            List<String[]> s = new ArrayList<>(5_000);
            List<Set<String>> f = new ArrayList<>(5_000);
            String[] kNames = new String[K];
            for (int k = 0; k < K; k++) kNames[k] = "ev_" + k;
            for (int i = 0; i < 5_000; i++) {
                s.add(kNames.clone());
                f.add(new HashSet<>(Arrays.asList(kNames)));
            }
            String ev = "ev_" + (K - 1);
            long ops = 5_000L * 100;
            bench(
                String.format("K=%2d intercepts: List.contains vs HashSet.contains", K),
                () -> dispatchSlow(s, ev, 100),
                () -> dispatchFast(f, ev, 100),
                ops, ops
            );
        }

        // --- phoenix-0002: pipe accumulation ---
        System.out.println();
        System.out.println("phoenix-0002: router scope pipe accumulation (P=2000 pipelines)");
        int P = 2_000;
        bench(
            "pipe_through: ArrayList dup-check vs HashSet dup-check",
            () -> pipeAccumulateSlow(P),
            () -> pipeAccumulateFast(P),
            P, P
        );

        System.out.println();
        System.out.println("Done.");
    }
}