stefanofago73 · January 20, 2026 15:24
diff --git a/CommonCloudEvents_Extensions.java b/CommonCloudEvents_Extensions.java
 import java.net.URI;
 import java.time.OffsetDateTime;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;

 import io.cloudevents.CloudEventExtension;
 import io.cloudevents.CloudEventExtensions;
 import io.cloudevents.core.extensions.impl.ExtensionUtils;

 /**
 * Generic base class for simple CloudEvents extensions backed by a 
 * fixed set of extension attributes.
 *
 * <p>
 * <strong>Mutability note:</strong> Instances of this class are mutable.
 * Methods such as {@code with(...)},
 * {@link #readFrom(io.cloudevents.CloudEventExtensions)},
 * {@link #overwriteFrom(io.cloudevents.CloudEventExtensions)} and
 * {@link #clear()} modify the internal state of the extension.
 *
 * <p>
 * {@code equals(Object)} and {@code hashCode()} are value-based and reflect the
 * current state of the extension. As a consequence, instances should not be
 * used as keys in hash-based collections (e.g. {@link java.util.HashMap},
 * {@link java.util.HashSet}) if they are expected to be mutated after
 * insertion.
 * 
 * <p>
 * This class is not thread-safe and is intended for single-threaded use during
 * CloudEvent construction or parsing.
 */
 public abstract class GenericCloudEventExtension<T extends GenericCloudEventExtension<T>>
 		implements CloudEventExtension {

 	private final Set<String> keys;
 	private final Map<String, Object> kv;

  /**
   *
   * Key sorting affects the sorting of extension features: this is to keep json rendering consistent
   *
   **/
 	protected GenericCloudEventExtension(String ... keys) {
 		Objects.requireNonNull(keys, "keys");
 		this.keys = Set.of(keys);
 		this.kv = preInitializeWithNull(keys, new LinkedHashMap<>(this.keys.size()));
 	}

 	@Override
 	public final Set<String> getKeys() {
 		return keys;
 	}

 	@Override
 	public final Object getValue(String key) {
 		validateKey(key);
 		return kv.get(key);
 	}

 	/**
 	 * Default read behavior: "merge" semantics.
 	 *
 	 * For each declared key, the current value is overwritten only if the incoming
 	 * event provides a non-null value. If the incoming value is null, the current
 	 * value is unchanged. This avoids losing pre-populated values when the event
 	 * does not carry the attribute.
 	 * 
 	 */
 	@Override
 	public void readFrom(CloudEventExtensions extensions) {
 		Objects.requireNonNull(extensions, "extensions");
 		for (String key : keys) {
 			Object incoming = extensions.getExtension(key);
 			if (incoming != null) {
 				kv.put(key, incoming);
 			}
 		}
 	}

 	/**
 	 * <p>
 	 * This method is typically used when rebuilding an extension instance directly
 	 * from a CloudEvent, rather than merging with locally-set values.
   *
 	 */
 	public void overwriteFrom(CloudEventExtensions extensions) {
 		Objects.requireNonNull(extensions, "extensions");
 		for (String key : keys) {
 			kv.put(key, extensions.getExtension(key));
 		}
 	}

 	/**
 	 * Clears all stored values (sets all keys to null).
 	 */
 	public T clear() {
 		for (String key : keys) {
 			kv.put(key, null);
 		}
 		return self();
 	}

 	@Override
 	public final boolean equals(Object o) {
 		if (this == o)
 			return true;
 		if (o == null || getClass() != o.getClass())
 			return false;
 		GenericCloudEventExtension<?> that = (GenericCloudEventExtension<?>) o;
 		return keys.equals(that.keys) && kv.equals(that.kv);
 	}

 	@Override
 	public final int hashCode() {
 		return Objects.hash(keys, kv);
 	}

 	@Override
 	public final String toString() {
 		StringBuilder sb = new StringBuilder(250).append(getClass().getSimpleName()).append('{');

 		boolean wroteAny = false;
 		Object v = null;
 		for (Map.Entry<String, Object> e : kv.entrySet()) {
 			v = e.getValue();
 			if (v != null) {
 				if (wroteAny)
 					sb.append(',');
 				sb.append(e.getKey()).append('=').append(v);
 				wroteAny = true;
 			}
 		}
 		return sb.append('}').toString();
 	}

  //----------------------------------------------------
  //
  // DSL Wither Sections
  //
  //----------------------------------------------------
  
 	public T with(String key, String value) {
 		return withInternal(key, value, kv);
 	}

 	public T with(String key, URI value) {
 		return withInternal(key, value, kv);
 	}

 	public T with(String key, OffsetDateTime value) {
 		return withInternal(key, value, kv);
 	}

 	public T with(String key, Number value) {
 		return withInternal(key, value, kv);
 	}

 	public T with(String key, Boolean value) {
 		return withInternal(key, value, kv);
 	}
  
  
 	// ===========================================
 	//
 	// Internals Section
 	//
 	// ===========================================

 	private final Map<String, Object> preInitializeWithNull(String[] keys, Map<String, Object> kv) {
 		for (String k : keys) {
 			kv.put(k, null);
 		}
 		return kv;
 	}

 	private final void validateKey(String key) {
 		if (!keys.contains(key)) {
 			throw ExtensionUtils.generateInvalidKeyException(getClass(), key);
 		}
 	}

 	@SuppressWarnings("unchecked")
 	private final T self() {
 		return (T) this;
 	}

 	protected final T withInternal(String key, Object value, Map<String, Object> kv) {
 		validateKey(key);
 		kv.put(key, value);
 		return self();
 	}

 }


 // --------------------------------------------------
 //
 // Here and example of usage of the base class.
 // The costructor is used to define the keys ordering and usage
 // Custom typed getter are possible.
 // Custom type wither are possible
 // 
 // --------------------------------------------------

 import java.util.Objects;

 import com.gewiss.cloudevents.extensions.GenericCloudEventExtension;

 public class AuthContextExtension extends GenericCloudEventExtension<AuthContextExtension>{

 	public enum AuthType{
 	  app_user,
 	  user,
 	  service_account,
 	  api_key,
 	  system,
 	  unauthenticated,
 	  unknown;
 	}
 	
 	public static final String AUTH_TYPE_KEY = "authtype";
 	public static final String AUTH_ID_KEY = "authid";
 	public static final String AUTH_CLAIMS_KEY = "authclaims";
 	
 	
 	public AuthContextExtension() {
 		super(AUTH_TYPE_KEY,AUTH_ID_KEY,AUTH_CLAIMS_KEY);
 	}
 	
 	public AuthContextExtension withAuthType(AuthType type) {
 		return with(AUTH_TYPE_KEY, Objects.requireNonNull(type, "auth-type").name());
 	}
 	
 	public AuthContextExtension withAuthId(String authid) {
 		return with(AUTH_ID_KEY, Objects.requireNonNull(authid, "auth-id"));
 	}
 	
 	public AuthContextExtension withAuthClaims(String claims) {
 		return with(AUTH_CLAIMS_KEY, Objects.requireNonNull(claims, "auth-claims"));
 	}
 	
 	public AuthType getAuthType() {
 		return AuthType.valueOf(getValue(AUTH_TYPE_KEY).toString());
 	}
 	
 	public String getAuthId() {
 		return String.valueOf(getValue(AUTH_ID_KEY));
 	}
 	
 	public String getAuthClaims() {
 		return String.valueOf(getValue(AUTH_CLAIMS_KEY));
 	}
 	
 }
	import java.net.URI;
	import java.time.OffsetDateTime;
	import java.util.LinkedHashMap;
	import java.util.Map;
	import java.util.Objects;
	import java.util.Set;

	import io.cloudevents.CloudEventExtension;
	import io.cloudevents.CloudEventExtensions;
	import io.cloudevents.core.extensions.impl.ExtensionUtils;

	/**
	* Generic base class for simple CloudEvents extensions backed by a
	* fixed set of extension attributes.
	*
	* <p>
	* <strong>Mutability note:</strong> Instances of this class are mutable.
	* Methods such as {@code with(...)},
	* {@link #readFrom(io.cloudevents.CloudEventExtensions)},
	* {@link #overwriteFrom(io.cloudevents.CloudEventExtensions)} and
	* {@link #clear()} modify the internal state of the extension.
	*
	* <p>
	* {@code equals(Object)} and {@code hashCode()} are value-based and reflect the
	* current state of the extension. As a consequence, instances should not be
	* used as keys in hash-based collections (e.g. {@link java.util.HashMap},
	* {@link java.util.HashSet}) if they are expected to be mutated after
	* insertion.
	*
	* <p>
	* This class is not thread-safe and is intended for single-threaded use during
	* CloudEvent construction or parsing.
	*/
	public abstract class GenericCloudEventExtension<T extends GenericCloudEventExtension<T>>
	implements CloudEventExtension {

	private final Set<String> keys;
	private final Map<String, Object> kv;

	/**
	*
	* Key sorting affects the sorting of extension features: this is to keep json rendering consistent
	*
	**/
	protected GenericCloudEventExtension(String ... keys) {
	Objects.requireNonNull(keys, "keys");
	this.keys = Set.of(keys);
	this.kv = preInitializeWithNull(keys, new LinkedHashMap<>(this.keys.size()));
	}

	@Override
	public final Set<String> getKeys() {
	return keys;
	}

	@Override
	public final Object getValue(String key) {
	validateKey(key);
	return kv.get(key);
	}

	/**
	* Default read behavior: "merge" semantics.
	*
	* For each declared key, the current value is overwritten only if the incoming
	* event provides a non-null value. If the incoming value is null, the current
	* value is unchanged. This avoids losing pre-populated values when the event
	* does not carry the attribute.
	*
	*/
	@Override
	public void readFrom(CloudEventExtensions extensions) {
	Objects.requireNonNull(extensions, "extensions");
	for (String key : keys) {
	Object incoming = extensions.getExtension(key);
	if (incoming != null) {
	kv.put(key, incoming);
	}
	}
	}

	/**
	* <p>
	* This method is typically used when rebuilding an extension instance directly
	* from a CloudEvent, rather than merging with locally-set values.
	*
	*/
	public void overwriteFrom(CloudEventExtensions extensions) {
	Objects.requireNonNull(extensions, "extensions");
	for (String key : keys) {
	kv.put(key, extensions.getExtension(key));
	}
	}

	/**
	* Clears all stored values (sets all keys to null).
	*/
	public T clear() {
	for (String key : keys) {
	kv.put(key, null);
	}
	return self();
	}

	@Override
	public final boolean equals(Object o) {
	if (this == o)
	return true;
	if (o == null \|\| getClass() != o.getClass())
	return false;
	GenericCloudEventExtension<?> that = (GenericCloudEventExtension<?>) o;
	return keys.equals(that.keys) && kv.equals(that.kv);
	}

	@Override
	public final int hashCode() {
	return Objects.hash(keys, kv);
	}

	@Override
	public final String toString() {
	StringBuilder sb = new StringBuilder(250).append(getClass().getSimpleName()).append('{');

	boolean wroteAny = false;
	Object v = null;
	for (Map.Entry<String, Object> e : kv.entrySet()) {
	v = e.getValue();
	if (v != null) {
	if (wroteAny)
	sb.append(',');
	sb.append(e.getKey()).append('=').append(v);
	wroteAny = true;
	}
	}
	return sb.append('}').toString();
	}

	//----------------------------------------------------
	//
	// DSL Wither Sections
	//
	//----------------------------------------------------

	public T with(String key, String value) {
	return withInternal(key, value, kv);
	}

	public T with(String key, URI value) {
	return withInternal(key, value, kv);
	}

	public T with(String key, OffsetDateTime value) {
	return withInternal(key, value, kv);
	}

	public T with(String key, Number value) {
	return withInternal(key, value, kv);
	}

	public T with(String key, Boolean value) {
	return withInternal(key, value, kv);
	}


	// ===========================================
	//
	// Internals Section
	//
	// ===========================================

	private final Map<String, Object> preInitializeWithNull(String[] keys, Map<String, Object> kv) {
	for (String k : keys) {
	kv.put(k, null);
	}
	return kv;
	}

	private final void validateKey(String key) {
	if (!keys.contains(key)) {
	throw ExtensionUtils.generateInvalidKeyException(getClass(), key);
	}
	}

	@SuppressWarnings("unchecked")
	private final T self() {
	return (T) this;
	}

	protected final T withInternal(String key, Object value, Map<String, Object> kv) {
	validateKey(key);
	kv.put(key, value);
	return self();
	}

	}


	// --------------------------------------------------
	//
	// Here and example of usage of the base class.
	// The costructor is used to define the keys ordering and usage
	// Custom typed getter are possible.
	// Custom type wither are possible
	//
	// --------------------------------------------------

	import java.util.Objects;

	import com.gewiss.cloudevents.extensions.GenericCloudEventExtension;

	public class AuthContextExtension extends GenericCloudEventExtension<AuthContextExtension>{

	public enum AuthType{
	app_user,
	user,
	service_account,
	api_key,
	system,
	unauthenticated,
	unknown;
	}

	public static final String AUTH_TYPE_KEY = "authtype";
	public static final String AUTH_ID_KEY = "authid";
	public static final String AUTH_CLAIMS_KEY = "authclaims";


	public AuthContextExtension() {
	super(AUTH_TYPE_KEY,AUTH_ID_KEY,AUTH_CLAIMS_KEY);
	}

	public AuthContextExtension withAuthType(AuthType type) {
	return with(AUTH_TYPE_KEY, Objects.requireNonNull(type, "auth-type").name());
	}

	public AuthContextExtension withAuthId(String authid) {
	return with(AUTH_ID_KEY, Objects.requireNonNull(authid, "auth-id"));
	}

	public AuthContextExtension withAuthClaims(String claims) {
	return with(AUTH_CLAIMS_KEY, Objects.requireNonNull(claims, "auth-claims"));
	}

	public AuthType getAuthType() {
	return AuthType.valueOf(getValue(AUTH_TYPE_KEY).toString());
	}

	public String getAuthId() {
	return String.valueOf(getValue(AUTH_ID_KEY));
	}

	public String getAuthClaims() {
	return String.valueOf(getValue(AUTH_CLAIMS_KEY));
	}

	}
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