java-topology/defects/odl/unit/OdlShardManagerSnapshotTest.java

package unit;

/**
 * CWE-407 unit test: OpenDaylight ShardManagerSnapshot.getShardList().contains()
 * Defect: ImmutableList<String>.contains() O(n) called per CreateShard during recovery
 * Fix:    ImmutableSet<String>.contains() O(1)
 *
 * slow(): ImmutableList — O(S) linear scan per shard lookup; S*S total during recovery
 * fast(): ImmutableSet  — O(1) hash lookup per shard; S total during recovery
 * Assert: slowOps > fastOps * 5   (S=200 shards → ~20000 vs ~200 comparisons)
 */
public class OdlShardManagerSnapshotTest {

    static long eqCount;

    static class ShardName {
        final String name;
        OdlShardManagerSnapshotTest.Counter counter;

        ShardName(String name, OdlShardManagerSnapshotTest.Counter c) {
            this.name = name;
            this.counter = c;
        }

        @Override
        public boolean equals(Object o) {
            if (counter != null) counter.increment();
            if (!(o instanceof ShardName)) return false;
            return name.equals(((ShardName) o).name);
        }

        @Override
        public int hashCode() {
            return name.hashCode();
        }

        @Override
        public String toString() { return name; }
    }

    static class Counter {
        long count = 0;
        void increment() { count++; }
    }

    /** Slow: ImmutableList — O(S) contains per lookup. */
    static long slow(int shardCount) {
        Counter c = new Counter();
        java.util.List<ShardName> shards = new java.util.ArrayList<>();
        for (int i = 0; i < shardCount; i++) {
            shards.add(new ShardName("shard-" + i, c));
        }
        com.google.common.collect.ImmutableList<ShardName> snapshot =
            com.google.common.collect.ImmutableList.copyOf(shards);

        // Simulate S shard creations, each checking if shard was in snapshot
        for (int i = 0; i < shardCount; i++) {
            ShardName query = new ShardName("shard-" + i, null);
            for (ShardName s : snapshot) {
                if (s.equals(query)) break;
            }
        }
        return c.count;
    }

    /** Fast: ImmutableSet — O(1) contains per lookup. */
    static long fast(int shardCount) {
        Counter c = new Counter();
        java.util.Set<ShardName> shards = new java.util.HashSet<>();
        for (int i = 0; i < shardCount; i++) {
            shards.add(new ShardName("shard-" + i, c));
        }
        com.google.common.collect.ImmutableSet<ShardName> snapshot =
            com.google.common.collect.ImmutableSet.copyOf(shards);

        for (int i = 0; i < shardCount; i++) {
            ShardName query = new ShardName("shard-" + i, null);
            snapshot.contains(query);
        }
        return c.count;
    }

    public static void main(String[] args) {
        int S = 200;
        int MULTIPLIER = 5;

        long sOps = slow(S);
        long fOps = fast(S);

        System.out.println("S=" + S + " shards");
        System.out.println("slow (ImmutableList.contains): " + sOps + " equals() calls");
        System.out.println("fast (ImmutableSet.contains):  " + fOps + " equals() calls");

        if (sOps > fOps * MULTIPLIER) {
            System.out.println("1/1 PASS (slow=" + sOps + " > fast*" + MULTIPLIER + "=" + (fOps * MULTIPLIER) + ")");
        } else {
            System.out.println("1/1 FAIL (slow=" + sOps + " not > fast*" + MULTIPLIER + "=" + (fOps * MULTIPLIER) + ")");
            System.exit(1);
        }
    }
}