Aerospike Dedupe

dedupe.java

	public boolean isDuplicate(String id) {
		Key key = new Key(namespace, set, id);
		LOG.debug("Checking if seen: " + id);

		// Check the record/bin a few times incase there is some write contention
		int count = 0;
		Boolean duplicate;
		do {
			duplicate = checkDuplicate(key);
		} while (duplicate == null && count++ < RETRY_COUNT);

		return duplicate == null || duplicate.booleanValue();
	}

	private Boolean checkDuplicate(Key key) {
		Record rec = client.get(null, key, bin);

		// Already written
		if (rec != null && rec.getValue(bin) != null && rec.getInt(bin) == 1) {
			return true;
		}

		WritePolicy wp = new WritePolicy();
		if (rec != null) {  // Record exists, bin is either 0 or missing, use check-and-set functionality to ensure same record is being updated
			wp.generationPolicy = GenerationPolicy.EXPECT_GEN_EQUAL;
			wp.generation = rec.generation;
		} else { // Record doesn't exist, use create only functionaity to ensure nothing else writes to the record first
			wp.recordExistsAction = RecordExistsAction.CREATE_ONLY;
		}

		try {
			client.put(wp, key, new Bin(bin, 1));
			return false;
		} catch (AerospikeException e) {
			LOG.warn("Error", e);
			// TODO: Check the error code for the Create Only/Invalid Generation error, throw RuntimeException if it's another error.
			return null;
		}
	}
	
	
	public void rollback(String id) {
		Key key = new Key(namespace, set, id);
		LOG.debug("Rolling back: " + id);
		client.put(null, key, new Bin(bin, 0));
	}