Package io.camunda.client.impl.oauth

Class OAuthCredentialsCache

java.lang.Object

io.camunda.client.impl.oauth.OAuthCredentialsCache

@ThreadSafe
public final class OAuthCredentialsCache
extends Object

Constructor Summary

Constructors

Constructor	Description
OAuthCredentialsCache()	Creates an in-memory-only credentials cache.
OAuthCredentialsCache(File cacheFile)	Creates a credentials cache backed by cacheFile.

Method Summary

Modifier and Type	Method	Description
CamundaClientCredentials	computeIfMissingOrInvalid(String clientId, SupplierWithIO<CamundaClientCredentials> zeebeClientCredentialsConsumer)
CamundaClientCredentials	computeIfMissingOrInvalid(String clientId, SupplierWithIO<CamundaClientCredentials> zeebeClientCredentialsConsumer, Runnable proactiveRefreshCallback, Duration proactiveTokenRefreshThreshold)	Returns a valid cached token, or fetches a new one if missing/invalid.
boolean	forceRefreshIfChanged(String clientId, SupplierWithIO<CamundaClientCredentials> credentialsSupplier)	Ensures that a fresh token is available in the cache, and returns true if the caller should retry its request (i.e. credentials were refreshed — either by this thread or by a concurrent one that completed while this thread was waiting for the lock).
Optional<CamundaClientCredentials>	get(String clientId)
OAuthCredentialsCache	put(String clientId, CamundaClientCredentials credentials)
void	putAndWrite(String clientId, CamundaClientCredentials credentials)	Atomically puts credentials into the cache and writes to disk.
OAuthCredentialsCache	readCache()
int	size()
<T> Optional<T>	withCache(String clientId, FunctionWithIO<CamundaClientCredentials,T> function)
void	writeCache()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

OAuthCredentialsCache

public OAuthCredentialsCache()

Creates an in-memory-only credentials cache. Equivalent to OAuthCredentialsCache(File) with null — no filesystem persistence; tokens live only for the lifetime of this instance.

OAuthCredentialsCache

public OAuthCredentialsCache(File cacheFile)

Creates a credentials cache backed by cacheFile. If cacheFile is null, the cache operates in memory only: readCache() and writeCache() become no-ops and tokens are not persisted across restarts. If cacheFile is non-null, the file (and its parent directories, if missing) are created on first write and used to round-trip credentials between runs.

Method Details

readCache

public OAuthCredentialsCache readCache()
                                throws IOException

Throws:

IOException

writeCache

public void writeCache()
                throws IOException

Throws:

IOException

get

public Optional<CamundaClientCredentials> get(String clientId)

computeIfMissingOrInvalid

public CamundaClientCredentials computeIfMissingOrInvalid(String clientId,
 SupplierWithIO<CamundaClientCredentials> zeebeClientCredentialsConsumer)
                                                   throws IOException

Throws:

IOException

computeIfMissingOrInvalid

public CamundaClientCredentials computeIfMissingOrInvalid(String clientId,
 SupplierWithIO<CamundaClientCredentials> zeebeClientCredentialsConsumer,
 Runnable proactiveRefreshCallback,
 Duration proactiveTokenRefreshThreshold)
                                                   throws IOException

Returns a valid cached token, or fetches a new one if missing/invalid. When a proactiveRefreshCallback is provided and the cached token is valid but within proactiveTokenRefreshThreshold of expiry (as determined by CamundaClientCredentials.shouldRefreshProactively(Duration)), the callback is invoked to trigger a background refresh while the still-valid token is returned immediately.

This method first checks the in-memory cache (a fast HashMap lookup) before falling back to reading from the on-disk YAML cache. Under high throughput (~300 req/s), this avoids hundreds of file reads per second while holding the synchronized lock.

Throws:

IOException

forceRefreshIfChanged

public boolean forceRefreshIfChanged(String clientId,
 SupplierWithIO<CamundaClientCredentials> credentialsSupplier)
                              throws IOException

Ensures that a fresh token is available in the cache, and returns true if the caller should retry its request (i.e. credentials were refreshed — either by this thread or by a concurrent one that completed while this thread was waiting for the lock).

When a concurrent call already refreshed the token (detected via a generation counter read before acquiring the monitor), the expensive OAuth HTTP call is skipped and true is returned immediately. This reduces lock hold time from N × ~200ms (where N is the number of concurrent 401 retries) to ~200ms + (N−1) × O(μs), preventing a cascading freeze of the HTTP client's I/O reactor.

Returns:

true if credentials were refreshed (by any thread) and the request should be retried; false if the freshly fetched credentials are identical to the previously cached ones (i.e. the 401 was not caused by a stale token)

Throws:

IOException

putAndWrite

public void putAndWrite(String clientId,
 CamundaClientCredentials credentials)
                 throws IOException

Atomically puts credentials into the cache and writes to disk. This method is synchronized on the same monitor as computeIfMissingOrInvalid(java.lang.String, io.camunda.client.impl.util.SupplierWithIO<io.camunda.client.impl.CamundaClientCredentials>), ensuring that a concurrent readCache() cannot clobber the in-memory state between the put and the write. This is designed for the background proactive refresh: the caller fetches the token outside any lock (the slow HTTP call), then calls this method to briefly acquire the monitor for the fast put+write.

Throws:

IOException

withCache

public <T> Optional<T> withCache(String clientId,
 FunctionWithIO<CamundaClientCredentials,T> function)
                          throws IOException

Throws:

IOException

put

public OAuthCredentialsCache put(String clientId,
 CamundaClientCredentials credentials)

size

public int size()