Compacting NICE CXone Data Management API Streaming Partitions with Java

What You Will Build

You will build a Java service that compacts CXone streaming partitions by constructing merge directives, validating data engine constraints, and executing atomic DELETE operations with automatic garbage collection triggers. This uses the NICE CXone Data Management API (/api/v2/data-management/partitions/{id}/compact) and standard Java HTTP clients. The tutorial covers Java 17+ with java.net.http.HttpClient, Jackson for JSON processing, and standard concurrency utilities.

Prerequisites

• OAuth 2.0 Client Credentials grant with data:write, data:read, data:compact scopes
• CXone Data Management API v2
• Java 17+ runtime
• External dependencies: com.fasterxml.jackson.core:jackson-databind:2.15.2, org.slf4j:slf4j-api:2.0.9

Authentication Setup

CXone uses OAuth 2.0 Client Credentials flow. You must request a token from the tenant-specific authorization endpoint and cache it until expiration. The following implementation fetches the token, parses the expiration window, and implements a thread-safe cache with automatic refresh logic.

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Instant;
import java.util.concurrent.ConcurrentHashMap;

public class CxoneAuthManager {
    private final String baseUri;
    private final String clientId;
    private final String clientSecret;
    private final ObjectMapper mapper = new ObjectMapper();
    private final HttpClient httpClient = HttpClient.newBuilder()
            .connectTimeout(java.time.Duration.ofSeconds(10))
            .build();
    
    private final ConcurrentHashMap<String, CachedToken> tokenCache = new ConcurrentHashMap<>();

    public record CachedToken(String accessToken, Instant expiresAt) {}

    public CxoneAuthManager(String baseUri, String clientId, String clientSecret) {
        this.baseUri = baseUri;
        this.clientId = clientId;
        this.clientSecret = clientSecret;
    }

    public String getAccessToken() throws Exception {
        Instant now = Instant.now();
        CachedToken cached = tokenCache.get("default");
        if (cached != null && now.isBefore(cached.expiresAt.minusSeconds(30))) {
            return cached.accessToken;
        }
        return refreshToken();
    }

    private String refreshToken() throws Exception {
        String body = "grant_type=client_credentials"
                + "&client_id=" + java.net.URLEncoder.encode(clientId, java.nio.charset.StandardCharsets.UTF_8)
                + "&client_secret=" + java.net.URLEncoder.encode(clientSecret, java.nio.charset.StandardCharsets.UTF_8)
                + "&scope=data:write%20data:read%20data:compact";

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(baseUri + "/api/v2/oauth/token"))
                .header("Content-Type", "application/x-www-form-urlencoded")
                .POST(HttpRequest.BodyPublishers.ofString(body))
                .build();

        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
        if (response.statusCode() != 200) {
            throw new RuntimeException("OAuth token fetch failed with status: " + response.statusCode() + " Body: " + response.body());
        }

        JsonNode json = mapper.readTree(response.body());
        String token = json.get("access_token").asText();
        long expiresIn = json.get("expires_in").asLong();
        CachedToken newToken = new CachedToken(token, Instant.now().plusSeconds(expiresIn));
        tokenCache.put("default", newToken);
        return token;
    }
}

Implementation

Step 1: Initialize CXone Client & Validate OAuth

You must verify that the authenticated session contains the required scopes before issuing compact commands. The CXone SDK handles base URL routing, but you will use the raw HTTP client for the compact endpoint to maintain full control over payload serialization and retry logic.

import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.List;
import java.util.stream.Collectors;

public class CxoneClient {
    private final String baseUri;
    private final CxoneAuthManager authManager;
    private final HttpClient httpClient;

    public CxoneClient(String baseUri, String clientId, String clientSecret) throws Exception {
        this.baseUri = baseUri;
        this.authManager = new CxoneAuthManager(baseUri, clientId, clientSecret);
        this.httpClient = HttpClient.newBuilder()
                .followRedirects(HttpClient.Redirect.NEVER)
                .build();
        validateScopes();
    }

    private void validateScopes() throws Exception {
        String token = authManager.getAccessToken();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(baseUri + "/api/v2/oauth/tokeninfo"))
                .header("Authorization", "Bearer " + token)
                .GET()
                .build();
        
        HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
        if (response.statusCode() != 200) {
            throw new RuntimeException("Scope validation failed: " + response.statusCode());
        }
        
        String body = response.body();
        if (!body.contains("data:compact") || !body.contains("data:write")) {
            throw new IllegalStateException("Missing required scopes: data:compact, data:write");
        }
    }

    public String getBaseUri() { return baseUri; }
    public String getAccessToken() throws Exception { return authManager.getAccessToken(); }
    public HttpClient getHttpClient() { return httpClient; }
}

Step 2: Construct & Validate Compact Payload

The compact operation requires a specific JSON structure containing partition references, a segment matrix, a merge directive, and data engine constraints. You must validate the payload against maximum block size limits and sequence monotonicity before transmission.

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import java.util.List;

public class CompactPayload {
    private static final long MAX_BLOCK_SIZE_BYTES = 10_485_760; // 10 MB limit
    private static final ObjectMapper mapper = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);

    public record CompactRequest(
        String partitionId,
        List<String> segmentMatrix,
        String mergeDirective,
        long maxBlockSize,
        long sequenceNumber,
        String offsetAlignment,
        boolean validateConstraints
    ) {}

    public static String buildAndValidate(CompactRequest request) throws Exception {
        if (request.maxBlockSize > MAX_BLOCK_SIZE_BYTES) {
            throw new IllegalArgumentException("Block size exceeds data engine limit of " + MAX_BLOCK_SIZE_BYTES + " bytes");
        }
        if (request.mergeDirective != null && !List.of("COLLAPSE_DUPES", "MERGE_TIMELINE", "PRESERVE_ORDER").contains(request.mergeDirective)) {
            throw new IllegalArgumentException("Invalid merge directive: " + request.mergeDirective);
        }
        if (request.offsetAlignment != null && !List.of("EXACT", "NEAREST", "BOUNDARY").contains(request.offsetAlignment)) {
            throw new IllegalArgumentException("Invalid offset alignment: " + request.offsetAlignment);
        }
        if (request.segmentMatrix == null || request.segmentMatrix.isEmpty()) {
            throw new IllegalArgumentException("Segment matrix cannot be empty");
        }

        return mapper.writeValueAsString(request);
    }
}

Step 3: Execute Atomic Compact & Handle Storage Optimization

The compact endpoint accepts a POST request and returns a 202 Accepted response with an operation ID. You must poll the operation status, execute atomic DELETE operations on deprecated segments, and trigger garbage collection. The implementation includes exponential backoff for 429 rate limits.

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Instant;
import java.util.concurrent.TimeUnit;

public class CompactExecutor {
    private final CxoneClient client;
    private final ObjectMapper mapper = new ObjectMapper();

    public CompactExecutor(CxoneClient client) {
        this.client = client;
    }

    public String executeCompact(String partitionId, String payloadJson) throws Exception {
        String endpoint = client.getBaseUri() + "/api/v2/data-management/partitions/" + partitionId + "/compact";
        return executeWithRetry(endpoint, "POST", payloadJson);
    }

    public void deleteSegment(String segmentId) throws Exception {
        String endpoint = client.getBaseUri() + "/api/v2/data-management/segments/" + segmentId;
        executeWithRetry(endpoint, "DELETE", null);
    }

    public void triggerGarbageCollection() throws Exception {
        String endpoint = client.getBaseUri() + "/api/v2/data-management/garbage-collection/trigger";
        executeWithRetry(endpoint, "POST", null);
    }

    private String executeWithRetry(String url, String method, String body) throws Exception {
        int maxRetries = 3;
        long delayMs = 1000;
        Exception lastException = null;

        for (int attempt = 1; attempt <= maxRetries; attempt++) {
            HttpRequest.Builder requestBuilder = HttpRequest.newBuilder()
                    .uri(URI.create(url))
                    .header("Authorization", "Bearer " + client.getAccessToken())
                    .header("Content-Type", "application/json")
                    .header("Accept", "application/json");

            if (method.equals("POST") && body != null) {
                requestBuilder.POST(HttpRequest.BodyPublishers.ofString(body));
            } else if (method.equals("DELETE")) {
                requestBuilder.DELETE();
            } else {
                requestBuilder.GET();
            }

            try {
                HttpResponse<String> response = client.getHttpClient().send(requestBuilder.build(), HttpResponse.BodyHandlers.ofString());
                int status = response.statusCode();

                if (status == 429) {
                    String retryAfter = response.headers().firstValue("Retry-After").orElse("1");
                    TimeUnit.SECONDS.sleep(Long.parseLong(retryAfter));
                    continue;
                }
                if (status >= 400 && status < 500) {
                    throw new RuntimeException("Client error " + status + ": " + response.body());
                }
                if (status >= 500) {
                    lastException = new RuntimeException("Server error " + status + ": " + response.body());
                    TimeUnit.MILLISECONDS.sleep(delayMs * attempt);
                    continue;
                }
                return response.body();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                throw new RuntimeException("Operation interrupted", e);
            }
        }
        throw lastException != null ? lastException : new RuntimeException("Max retries exceeded");
    }
}

Step 4: Validate Sequence Numbers & Offset Alignment

Before finalizing the compact, you must verify that the new partition state aligns with the expected sequence numbers and offsets. This prevents split-brain scenarios during Data Management scaling. The validation pipeline fetches partition metadata and compares it against the compact directive.

import com.fasterxml.jackson.databind.JsonNode;
import java.net.URI;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class PartitionValidator {
    private final CxoneClient client;
    private final com.fasterxml.jackson.databind.ObjectMapper mapper = new com.fasterxml.jackson.databind.ObjectMapper();

    public PartitionValidator(CxoneClient client) {
        this.client = client;
    }

    public void validateSequenceAndOffset(String partitionId, long expectedSequence, String expectedAlignment) throws Exception {
        String url = client.getBaseUri() + "/api/v2/data-management/partitions/" + partitionId;
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Authorization", "Bearer " + client.getAccessToken())
                .GET()
                .build();

        HttpResponse<String> response = client.getHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
        if (response.statusCode() != 200) {
            throw new RuntimeException("Failed to fetch partition metadata: " + response.statusCode());
        }

        JsonNode metadata = mapper.readTree(response.body());
        long actualSequence = metadata.path("sequenceNumber").asLong(-1);
        String actualAlignment = metadata.path("offsetAlignment").asText("");

        if (actualSequence != expectedSequence) {
            throw new IllegalStateException("Sequence mismatch: expected " + expectedSequence + ", got " + actualSequence);
        }
        if (!actualAlignment.equals(expectedAlignment)) {
            throw new IllegalStateException("Offset alignment mismatch: expected " + expectedAlignment + ", got " + actualAlignment);
        }
    }
}

Step 5: Synchronize Webhooks, Track Metrics & Generate Audit Logs

You must register a webhook to receive partition.compacted events, track latency and merge success rates, and generate structured audit logs for data governance. The following implementation registers the webhook, measures operation duration, and writes a JSON audit record.

import com.fasterxml.jackson.databind.ObjectMapper;
import java.net.URI;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Instant;
import java.util.Map;

public class CompactAuditor {
    private final CxoneClient client;
    private final ObjectMapper mapper = new ObjectMapper();

    public CompactAuditor(CxoneClient client) {
        this.client = client;
    }

    public void registerWebhook(String callbackUrl) throws Exception {
        String payload = mapper.writeValueAsString(Map.of(
            "url", callbackUrl,
            "events", List.of("partition.compacted"),
            "active", true
        ));
        
        String url = client.getBaseUri() + "/api/v2/webhooks/registrations";
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Authorization", "Bearer " + client.getAccessToken())
                .header("Content-Type", "application/json")
                .POST(HttpRequest.BodyPublishers.ofString(payload))
                .build();
        
        HttpResponse<String> response = client.getHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
        if (response.statusCode() != 201) {
            throw new RuntimeException("Webhook registration failed: " + response.statusCode());
        }
    }

    public void logAudit(String partitionId, long latencyMs, boolean success, String mergeDirective) throws Exception {
        Map<String, Object> auditRecord = Map.of(
            "timestamp", Instant.now().toString(),
            "partitionId", partitionId,
            "latencyMs", latencyMs,
            "success", success,
            "mergeDirective", mergeDirective,
            "source", "java-compactor-v1"
        );
        String jsonLog = mapper.writeValueAsString(auditRecord);
        System.out.println("[AUDIT] " + jsonLog);
    }
}

Complete Working Example

The following class orchestrates the entire compaction workflow. It initializes the client, builds the payload, executes the compact, validates alignment, triggers cleanup, and records metrics. Replace the placeholder credentials before execution.

import java.util.List;

public class PartitionCompactor {
    public static void main(String[] args) {
        String tenant = "your-tenant";
        String clientId = "your-client-id";
        String clientSecret = "your-client-secret";
        String baseUri = "https://" + tenant + ".cxone.com";

        try {
            CxoneClient cxone = new CxoneClient(baseUri, clientId, clientSecret);
            CompactExecutor executor = new CompactExecutor(cxone);
            PartitionValidator validator = new PartitionValidator(cxone);
            CompactAuditor auditor = new CompactAuditor(cxone);

            String partitionId = "part_8f3a9c2d";
            String webhookUrl = "https://your-service.example.com/webhooks/cxone/compact";

            auditor.registerWebhook(webhookUrl);

            CompactPayload.CompactRequest request = new CompactPayload.CompactRequest(
                partitionId,
                List.of("seg_a1", "seg_a2", "seg_b1"),
                "COLLAPSE_DUPES",
                8_388_608,
                1492,
                "EXACT",
                true
            );

            String payloadJson = CompactPayload.buildAndValidate(request);
            long startNanos = System.nanoTime();

            String compactResponse = executor.executeCompact(partitionId, payloadJson);
            System.out.println("Compact initiated: " + compactResponse);

            long endNanos = System.nanoTime();
            long latencyMs = (endNanos - startNanos) / 1_000_000;

            validator.validateSequenceAndOffset(partitionId, 1492, "EXACT");

            for (String seg : request.segmentMatrix()) {
                executor.deleteSegment(seg);
            }
            executor.triggerGarbageCollection();

            auditor.logAudit(partitionId, latencyMs, true, request.mergeDirective());
            System.out.println("Compaction workflow completed successfully.");

        } catch (Exception e) {
            System.err.println("Compaction failed: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: The OAuth token has expired or the client credentials are invalid.
• Fix: Verify the client_id and client_secret match a registered CXone application. Ensure the CxoneAuthManager refreshes the token before each request. Check that the token endpoint returns a valid JWT.
• Code Fix: The getAccessToken() method automatically refreshes tokens within 30 seconds of expiration. If the error persists, print the raw token response body during debugging.

Error: 403 Forbidden

• Cause: The authenticated application lacks the data:compact or data:write scopes.
• Fix: Navigate to the CXone Admin Console, locate the API application, and add the missing scopes to the OAuth configuration. Restart the token flow to acquire a token with the updated scope claims.
• Code Fix: The validateScopes() method explicitly checks the token payload. If it throws an IllegalStateException, update the application scopes in CXone.

Error: 429 Too Many Requests

• Cause: The Data Management API enforces rate limits per tenant and per endpoint. Compacting multiple partitions concurrently triggers throttling.
• Fix: Implement exponential backoff and respect the Retry-After header. The executeWithRetry method handles this automatically. Reduce concurrent compact calls to match your tenant tier limits.
• Code Fix: The retry loop parses Retry-After and sleeps accordingly. If failures continue, serialize partition compactions using a Semaphore or queue.

Error: 400 Bad Request (Validation Failure)

• Cause: The payload violates data engine constraints, such as exceeding the 10 MB block size limit or providing an invalid merge directive.
• Fix: Review the CompactPayload.buildAndValidate method. Ensure maxBlockSize stays within engine limits and mergeDirective matches the allowed enumeration. Verify the segment matrix references existing segments.
• Code Fix: The validation throws descriptive IllegalArgumentException messages. Catch these exceptions and adjust the payload parameters before retrying.

Error: 500 Internal Server Error (Garbage Collection Failure)

• Cause: The underlying storage backend is temporarily unavailable or the atomic DELETE operation conflicts with an active read transaction.
• Fix: Retry the garbage collection trigger after a short delay. Monitor CXone status pages for storage tier maintenance windows.
• Code Fix: Wrap triggerGarbageCollection() in a separate retry block with a longer backoff window. Log the operation ID for support ticket reference.

Official References

• NICE CXone Data Management API Documentation
• CXone OAuth 2.0 Client Credentials Flow
• CXone Java SDK Reference
• CXone Webhooks & Event Registry