Add ChainedDelegateConsentService with pluggable vote strategy

Introduce some plumbing utils to combine consent votes.

hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/7_6_0/6366-consent-plumbing.yaml

@@ -0,0 +1,4 @@
+---
+type: add
+issue: 6366
+title: "Add plumbing for combining IConsentServices with different vote tally strategies"

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/interceptor/consent/ConsentOperationStatusEnum.java

@@ -21,7 +21,7 @@ package ca.uhn.fhir.rest.server.interceptor.consent;
 
 import java.util.stream.Stream;
 
-public enum ConsentOperationStatusEnum {
+public enum ConsentOperationStatusEnum implements IConsentVote {
 
 	/**
 	 * The requested operation cannot proceed, and an operation outcome suitable for
@@ -59,53 +59,52 @@ public enum ConsentOperationStatusEnum {
 				return 0;
 		}
 	}
+
+	/**
+	 * Does this vote abstain from the verdict?
+	 * I.e. this == PROCEED
+	 * @return true if this vote can be ignored
+	 */
+	boolean isAbstain() {
+		return this == PROCEED;
+	}
+
+	/**
+	 * Does this vote participate from the verdict?
+	 * I.e. this != PROCEED
+	 * @return false if this vote can be ignored
+	 */
+	boolean isActiveVote() {
+		return this != PROCEED;
+	}
+
+	@Override
+	public ConsentOperationStatusEnum getStatus() {
+		return this;
+	}
+
 	/**
 	 * Evaluate verdicts in order, taking the first "decision" (i.e. first non-PROCEED) verdict.
 	 *
 	 * @return the first decisive verdict, or PROCEED when empty or all PROCEED.
 	 */
+	public static ConsentOperationStatusEnum serialReduce(Stream<ConsentOperationStatusEnum> theVoteStream) {
+		return IConsentVote.serialReduce(PROCEED, theVoteStream);
+	}
+
+	public static ConsentOperationStatusEnum parallelReduce(Stream<ConsentOperationStatusEnum> theVoteStream) {
+		return IConsentVote.parallelReduce(PROCEED, theVoteStream);
+	}
+
+	/** @deprecated for rename */
+	@Deprecated(forRemoval = true)
 	public static ConsentOperationStatusEnum serialEvaluate(Stream<ConsentOperationStatusEnum> theVoteStream) {
-		return theVoteStream.filter(verdict -> PROCEED != verdict).findFirst().orElse(PROCEED);
+		return serialReduce(theVoteStream);
 	}
 
-	/**
-	 * Evaluate verdicts in order, taking the first "decision" (i.e. first non-PROCEED) verdict.
-	 *
-	 * @param theNextVerdict the next verdict to consider
-	 * @return the combined verdict
-	 */
-	public ConsentOperationStatusEnum serialReduce(ConsentOperationStatusEnum theNextVerdict) {
-		if (this != PROCEED) {
-			return this;
-		} else {
-			return theNextVerdict;
-		}
-	}
-
-	/**
-	 * Evaluate all verdicts together, allowing any to veto (i.e. REJECT) the operation.
-	 * <ul>
-	 * <li>If any vote is REJECT, then the result is REJECT.
-	 * <li>If no vote is REJECT, and any vote is AUTHORIZED, then the result is AUTHORIZED.
-	 * <li>If no vote is REJECT or AUTHORIZED, the result is PROCEED.
-	 * </ul>
-	 *
-	 * @return REJECT if any reject, AUTHORIZED if no REJECT and some AUTHORIZED, PROCEED if empty or all PROCEED
-	 */
+	/** @deprecated for rename */
+	@Deprecated(forRemoval = true)
 	public static ConsentOperationStatusEnum parallelEvaluate(Stream<ConsentOperationStatusEnum> theVoteStream) {
-		return theVoteStream.reduce(PROCEED, ConsentOperationStatusEnum::parallelReduce);
-	}
-
-	/**
-	 * Evaluate two verdicts together, allowing either to veto (i.e. REJECT) the operation.
-	 *
-	 * @return REJECT if either reject, AUTHORIZED if no REJECT and some AUTHORIZED, PROCEED otherwise
-	 */
-	public ConsentOperationStatusEnum parallelReduce(ConsentOperationStatusEnum theNextVerdict) {
-		if (theNextVerdict.getPrecedence() > this.getPrecedence()) {
-			return theNextVerdict;
-		} else {
-			return this;
-		}
+		return parallelReduce(theVoteStream);
 	}
 }

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/interceptor/consent/ConsentOutcome.java

@@ -23,7 +23,9 @@ import org.apache.commons.lang3.Validate;
 import org.hl7.fhir.instance.model.api.IBaseOperationOutcome;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 
-public class ConsentOutcome {
+import java.util.stream.Stream;
+
+public class ConsentOutcome implements IConsentVote {
 
 	/**
 	 * Convenience constant containing <code>new ConsentOutcome(ConsentOperationStatusEnum.PROCEED)</code>
@@ -67,6 +69,29 @@ public class ConsentOutcome {
 		myResource = theResource;
 	}
 
+	/**
+	 * Evaluate all verdicts together, allowing any to veto (i.e. REJECT) the operation.
+	 * <ul>
+	 * <li>If any vote is REJECT, then the result is a REJECT vote.
+	 * <li>If no vote is REJECT, and any vote is AUTHORIZED, then the result is one of the AUTHORIZED votes.
+	 * <li>If no vote is REJECT or AUTHORIZED, the result is a PROCEED vote.
+	 * </ul>
+	 *
+	 * @return REJECT if any reject, AUTHORIZED if no REJECT and some AUTHORIZED, PROCEED if empty or all PROCEED
+	 */
+	public static ConsentOutcome parallelReduce(Stream<ConsentOutcome> theOutcomes) {
+		return IConsentVote.parallelReduce(ConsentOutcome.PROCEED, theOutcomes);
+	}
+
+	/**
+	 * Evaluate verdicts in order, taking the first "decision" (i.e. first non-PROCEED) verdict.
+	 *
+	 * @return the first decisive verdict, or theSeed when empty or all PROCEED.
+	 */
+	public static ConsentOutcome serialReduce(Stream<ConsentOutcome> theStream) {
+		return IConsentVote.serialReduce(ConsentOutcome.PROCEED, theStream);
+	}
+
 	public ConsentOperationStatusEnum getStatus() {
 		return myStatus;
 	}

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/interceptor/consent/ConstantConsentService.java

@@ -0,0 +1,48 @@
+package ca.uhn.fhir.rest.server.interceptor.consent;
+
+import ca.uhn.fhir.rest.api.server.RequestDetails;
+import jakarta.annotation.Nonnull;
+import org.hl7.fhir.instance.model.api.IBaseResource;
+
+/**
+ * Consent Service that returns a fixed verdict.
+ */
+public class ConstantConsentService implements IConsentService {
+	@Nonnull
+	final ConsentOutcome myResult;
+
+	public static ConstantConsentService constantService(ConsentOperationStatusEnum theResult) {
+		return new ConstantConsentService(new ConsentOutcome(theResult));
+	}
+
+	public ConstantConsentService(@Nonnull ConsentOutcome theResult) {
+		myResult = theResult;
+	}
+
+	private @Nonnull ConsentOutcome getOutcome() {
+		return myResult;
+	}
+
+	@Override
+	public ConsentOutcome startOperation(RequestDetails theRequestDetails, IConsentContextServices theContextServices) {
+		return getOutcome();
+	}
+
+	@Override
+	public boolean shouldProcessCanSeeResource(
+			RequestDetails theRequestDetails, IConsentContextServices theContextServices) {
+		return myResult.getStatus().isActiveVote();
+	}
+
+	@Override
+	public ConsentOutcome canSeeResource(
+			RequestDetails theRequestDetails, IBaseResource theResource, IConsentContextServices theContextServices) {
+		return getOutcome();
+	}
+
+	@Override
+	public ConsentOutcome willSeeResource(
+			RequestDetails theRequestDetails, IBaseResource theResource, IConsentContextServices theContextServices) {
+		return getOutcome();
+	}
+}

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/interceptor/consent/IConsentVote.java

@@ -0,0 +1,71 @@
+package ca.uhn.fhir.rest.server.interceptor.consent;
+
+import java.util.stream.Stream;
+
+/**
+ * Something that produces a vote, along with static
+ * tools for combining votes.
+ */
+public interface IConsentVote {
+	/**
+	 * Get the vote
+	 * @return the vote
+	 */
+	ConsentOperationStatusEnum getStatus();
+
+	/**
+	 * Evaluate all verdicts together, allowing any to veto (i.e. REJECT) the operation.
+	 * <ul>
+	 * <li>If any vote is REJECT, then the result is REJECT.
+	 * <li>If no vote is REJECT, and any vote is AUTHORIZED, then the result is AUTHORIZED.
+	 * <li>If no vote is REJECT or AUTHORIZED, the result is PROCEED.
+	 * </ul>
+	 *
+	 * @return REJECT if any reject, AUTHORIZED if no REJECT and some AUTHORIZED, PROCEED if empty or all PROCEED
+	 */
+	static <T extends IConsentVote> T parallelReduce(T theSeed, Stream<T> theVoteStream) {
+		return theVoteStream.reduce(theSeed, IConsentVote::parallelReduce);
+	}
+
+	/**
+	 * Evaluate two votes together, allowing either to veto (i.e. REJECT) the operation.
+	 *
+	 * @return REJECT if either reject, AUTHORIZED if no REJECT and some AUTHORIZED, PROCEED otherwise
+	 */
+	static <T extends IConsentVote> T parallelReduce(T theAccumulator, T theNextVoter) {
+		if (theNextVoter.getStatus().getPrecedence()
+				< theAccumulator.getStatus().getPrecedence()) {
+			return theAccumulator;
+		} else {
+			return theNextVoter;
+		}
+	}
+
+	/**
+	 * Evaluate verdicts in order, taking the first "decision" (i.e. first non-PROCEED) verdict.
+	 *
+	 * @return the first decisive verdict, or theSeed when empty or all PROCEED.
+	 */
+	static <T extends IConsentVote> T serialReduce(T theSeed, Stream<T> theVoterStream) {
+		return theVoterStream.filter(IConsentVote::isActiveVote).findFirst().orElse(theSeed);
+	}
+
+	/**
+	 * Evaluate verdicts in order, taking the first "decision" (i.e. first non-PROCEED) verdict.
+	 *
+	 * @param theAccumulator the verdict so fat
+	 * @param theNextVoter the next verdict to consider
+	 * @return the combined verdict
+	 */
+	static <T extends IConsentVote> T serialReduce(T theAccumulator, T theNextVoter) {
+		if (theAccumulator.getStatus().isAbstain()) {
+			return theNextVoter;
+		} else {
+			return theAccumulator;
+		}
+	}
+
+	private static <T extends IConsentVote> boolean isActiveVote(T nextVoter) {
+		return nextVoter.getStatus().isActiveVote();
+	}
+}

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/interceptor/consent/MultiDelegateConsentService.java

@@ -0,0 +1,74 @@
+package ca.uhn.fhir.rest.server.interceptor.consent;
+
+import ca.uhn.fhir.rest.api.server.RequestDetails;
+import jakarta.annotation.Nonnull;
+import org.hl7.fhir.instance.model.api.IBaseResource;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+/**
+ * IConsentService combiner over several delegates with pluggable combination strategy
+ */
+public class MultiDelegateConsentService implements IConsentService {
+	private final Collection<IConsentService> myDelegates;
+	private final Function<Stream<ConsentOutcome>, ConsentOutcome> myVoteCombiner;
+
+	/**
+	 * Combine several consent services allowing any to veto.
+	 */
+	public static @Nonnull MultiDelegateConsentService withParallelVoting(
+			@Nonnull List<IConsentService> theDelegateConsentServices) {
+		return new MultiDelegateConsentService(ConsentOutcome::parallelReduce, theDelegateConsentServices);
+	}
+
+	/**
+	 * Combine several consent services with first non-PROCEED vote win.
+	 */
+	public static @Nonnull MultiDelegateConsentService withSerialVoting(
+			@Nonnull List<IConsentService> theDelegateConsentServices) {
+		return new MultiDelegateConsentService(ConsentOutcome::serialReduce, theDelegateConsentServices);
+	}
+
+	private MultiDelegateConsentService(
+			Function<Stream<ConsentOutcome>, ConsentOutcome> theVoteCombiner,
+			Collection<IConsentService> theDelegates) {
+		myVoteCombiner = theVoteCombiner;
+		myDelegates = theDelegates;
+	}
+
+	@Override
+	public ConsentOutcome startOperation(RequestDetails theRequestDetails, IConsentContextServices theContextServices) {
+		return myVoteCombiner.apply(myDelegates.stream()
+				.map(nextDelegate -> nextDelegate.startOperation(theRequestDetails, theContextServices)));
+	}
+
+	/**
+	 * @return true if any of the delegates return true.
+	 */
+	@Override
+	public boolean shouldProcessCanSeeResource(
+			RequestDetails theRequestDetails, IConsentContextServices theContextServices) {
+		return myDelegates.stream()
+				.map(nextDelegate -> nextDelegate.shouldProcessCanSeeResource(theRequestDetails, theContextServices))
+				.filter(nextShould -> nextShould)
+				.findFirst()
+				.orElse(Boolean.FALSE);
+	}
+
+	@Override
+	public ConsentOutcome canSeeResource(
+			RequestDetails theRequestDetails, IBaseResource theResource, IConsentContextServices theContextServices) {
+		return myVoteCombiner.apply(myDelegates.stream()
+				.map(nextDelegate -> nextDelegate.canSeeResource(theRequestDetails, theResource, theContextServices)));
+	}
+
+	@Override
+	public ConsentOutcome willSeeResource(
+			RequestDetails theRequestDetails, IBaseResource theResource, IConsentContextServices theContextServices) {
+		return myVoteCombiner.apply(myDelegates.stream()
+				.map(nextDelegate -> nextDelegate.willSeeResource(theRequestDetails, theResource, theContextServices)));
+	}
+}

hapi-fhir-server/src/test/java/ca/uhn/fhir/rest/server/interceptor/consent/ConsentOperationStatusEnumTest.java

@@ -1,130 +1,14 @@
 package ca.uhn.fhir.rest.server.interceptor.consent;
 
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.CsvSource;
-
-import java.util.Arrays;
-import java.util.stream.Stream;
 
 import static ca.uhn.fhir.rest.server.interceptor.consent.ConsentOperationStatusEnum.AUTHORIZED;
 import static ca.uhn.fhir.rest.server.interceptor.consent.ConsentOperationStatusEnum.PROCEED;
 import static ca.uhn.fhir.rest.server.interceptor.consent.ConsentOperationStatusEnum.REJECT;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class ConsentOperationStatusEnumTest {
 
-	/**
-	 * With "serial" evaluation, the first non-PROCEED verdict wins.
-	 */
-	@ParameterizedTest
-	@CsvSource(textBlock = """
-		REJECT     REJECT     REJECT    , REJECT
-		REJECT     REJECT     PROCEED   , REJECT
-		REJECT     REJECT     AUTHORIZED, REJECT
-		REJECT     PROCEED    REJECT    , REJECT
-		REJECT     PROCEED    PROCEED   , REJECT
-		REJECT     PROCEED    AUTHORIZED, REJECT
-		REJECT     AUTHORIZED REJECT    , REJECT
-		REJECT     AUTHORIZED PROCEED   , REJECT
-		REJECT     AUTHORIZED AUTHORIZED, REJECT
-		PROCEED    REJECT     REJECT    , REJECT
-		PROCEED    REJECT     PROCEED   , REJECT
-		PROCEED    REJECT     AUTHORIZED, REJECT
-		PROCEED    PROCEED    REJECT    , REJECT
-		PROCEED    PROCEED    PROCEED   , PROCEED
-		PROCEED    PROCEED    AUTHORIZED, AUTHORIZED
-		PROCEED    AUTHORIZED REJECT    , AUTHORIZED
-		PROCEED    AUTHORIZED PROCEED   , AUTHORIZED
-		PROCEED    AUTHORIZED AUTHORIZED, AUTHORIZED
-		AUTHORIZED REJECT     REJECT    , AUTHORIZED
-		AUTHORIZED REJECT     PROCEED   , AUTHORIZED
-		AUTHORIZED REJECT     AUTHORIZED, AUTHORIZED
-		AUTHORIZED PROCEED    REJECT    , AUTHORIZED
-		AUTHORIZED PROCEED    PROCEED   , AUTHORIZED
-		AUTHORIZED PROCEED    AUTHORIZED, AUTHORIZED
-		AUTHORIZED AUTHORIZED REJECT    , AUTHORIZED
-		AUTHORIZED AUTHORIZED PROCEED   , AUTHORIZED
-		AUTHORIZED AUTHORIZED AUTHORIZED, AUTHORIZED
-		""")
-	void testSerialEvaluation_choosesFirstVerdict(String theInput, ConsentOperationStatusEnum theExpectedResult) {
-	    // given
-		Stream<ConsentOperationStatusEnum> consentOperationStatusEnumStream = Arrays.stream(theInput.split(" +"))
-			.map(String::trim)
-			.map(ConsentOperationStatusEnum::valueOf);
-
-		// when
-		ConsentOperationStatusEnum result = ConsentOperationStatusEnum.serialEvaluate(consentOperationStatusEnumStream);
-
-		assertEquals(theExpectedResult, result);
-	}
-
-	@ParameterizedTest
-	@CsvSource(textBlock = """
-		REJECT    , REJECT    , REJECT
-		REJECT    , PROCEED   , REJECT
-		REJECT    , AUTHORIZED, REJECT
-		AUTHORIZED, REJECT    , AUTHORIZED
-		AUTHORIZED, PROCEED   , AUTHORIZED
-		AUTHORIZED, AUTHORIZED, AUTHORIZED
-		PROCEED   , REJECT    , REJECT
-		PROCEED   , PROCEED   , PROCEED
-		PROCEED   , AUTHORIZED, AUTHORIZED
-		""")
-	void testSerialReduction_choosesFirstVerdict(ConsentOperationStatusEnum theFirst, ConsentOperationStatusEnum theSecond, ConsentOperationStatusEnum theExpectedResult) {
-
-		// when
-		ConsentOperationStatusEnum result = theFirst.serialReduce(theSecond);
-
-		assertEquals(theExpectedResult, result);
-	}
-
-
-	/**
-	 * With "parallel" evaluation, the "strongest" verdict wins.
-	 * REJECT > AUTHORIZED > PROCEED.
-	 */
-	@ParameterizedTest
-	@CsvSource(textBlock = """
-		REJECT     REJECT     REJECT    , REJECT
-		REJECT     REJECT     PROCEED   , REJECT
-		REJECT     REJECT     AUTHORIZED, REJECT
-		REJECT     PROCEED    REJECT    , REJECT
-		REJECT     PROCEED    PROCEED   , REJECT
-		REJECT     PROCEED    AUTHORIZED, REJECT
-		REJECT     AUTHORIZED REJECT    , REJECT
-		REJECT     AUTHORIZED PROCEED   , REJECT
-		REJECT     AUTHORIZED AUTHORIZED, REJECT
-		PROCEED    REJECT     REJECT    , REJECT
-		PROCEED    REJECT     PROCEED   , REJECT
-		PROCEED    REJECT     AUTHORIZED, REJECT
-		PROCEED    PROCEED    REJECT    , REJECT
-		PROCEED    PROCEED    PROCEED   , PROCEED
-		PROCEED    PROCEED    AUTHORIZED, AUTHORIZED
-		PROCEED    AUTHORIZED REJECT    , REJECT
-		PROCEED    AUTHORIZED PROCEED   , AUTHORIZED
-		PROCEED    AUTHORIZED AUTHORIZED, AUTHORIZED
-		AUTHORIZED REJECT     REJECT    , REJECT
-		AUTHORIZED REJECT     PROCEED   , REJECT
-		AUTHORIZED REJECT     AUTHORIZED, REJECT
-		AUTHORIZED PROCEED    REJECT    , REJECT
-		AUTHORIZED PROCEED    PROCEED   , AUTHORIZED
-		AUTHORIZED PROCEED    AUTHORIZED, AUTHORIZED
-		AUTHORIZED AUTHORIZED REJECT    , REJECT
-		AUTHORIZED AUTHORIZED PROCEED   , AUTHORIZED
-		AUTHORIZED AUTHORIZED AUTHORIZED, AUTHORIZED
-		""")
-	void testParallelReduction_strongestVerdictWins(String theInput, ConsentOperationStatusEnum theExpectedResult) {
-		// given
-		Stream<ConsentOperationStatusEnum> consentOperationStatusEnumStream = Arrays.stream(theInput.split(" +"))
-			.map(String::trim)
-			.map(ConsentOperationStatusEnum::valueOf);
-
-		// when
-		ConsentOperationStatusEnum result = ConsentOperationStatusEnum.parallelEvaluate(consentOperationStatusEnumStream);
-
-		assertEquals(theExpectedResult, result);
-	}
 
 	@Test
 	void testStrengthOrder() {

hapi-fhir-server/src/test/java/ca/uhn/fhir/rest/server/interceptor/consent/ConstantConsentServiceTest.java

@@ -0,0 +1,70 @@
+package ca.uhn.fhir.rest.server.interceptor.consent;
+
+import ca.uhn.fhir.rest.api.server.SystemRequestDetails;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.EnumSource;
+
+import static ca.uhn.fhir.rest.server.interceptor.consent.IConsentContextServices.NULL_IMPL;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ConstantConsentServiceTest {
+	SystemRequestDetails mySrd = new SystemRequestDetails();
+
+	@ParameterizedTest
+	@EnumSource(ConsentOperationStatusEnum.class)
+	void testStartOperation(ConsentOperationStatusEnum theStatus) {
+	    // given
+		var svc = ConstantConsentService.constantService(theStatus);
+
+	    // when
+		var outcome = svc.startOperation(mySrd,NULL_IMPL);
+
+	    // then
+	    assertEquals(outcome.getStatus(), theStatus);
+	}
+
+
+	/**
+	 * There's no point calling canSee if we return PROCEED.
+	 */
+	@ParameterizedTest
+	@EnumSource(ConsentOperationStatusEnum.class)
+	void testShouldProcessCanSeeResource(ConsentOperationStatusEnum theStatus) {
+		// given
+		var svc = ConstantConsentService.constantService(theStatus);
+
+		// when
+		boolean outcome = svc.shouldProcessCanSeeResource(mySrd,NULL_IMPL);
+
+		// then there's no point calling canSee if we return PROCEED.
+		boolean isNotAbstain = theStatus != ConsentOperationStatusEnum.PROCEED;
+		assertEquals(outcome, isNotAbstain);
+	}
+
+	@ParameterizedTest
+	@EnumSource(ConsentOperationStatusEnum.class)
+	void testCanSeeResource(ConsentOperationStatusEnum theStatus) {
+		// given
+		var svc = ConstantConsentService.constantService(theStatus);
+
+		// when
+		var outcome = svc.canSeeResource(mySrd, null, NULL_IMPL);
+
+		// then
+		assertEquals(outcome.getStatus(), theStatus);
+	}
+
+
+	@ParameterizedTest
+	@EnumSource(ConsentOperationStatusEnum.class)
+	void testWillSeeResource(ConsentOperationStatusEnum theStatus) {
+		// given
+		var svc = ConstantConsentService.constantService(theStatus);
+
+		// when
+		var outcome = svc.willSeeResource(mySrd, null, NULL_IMPL);
+
+		// then
+		assertEquals(outcome.getStatus(), theStatus);
+	}
+}

hapi-fhir-server/src/test/java/ca/uhn/fhir/rest/server/interceptor/consent/IConsentVoteTest.java

@@ -0,0 +1,156 @@
+package ca.uhn.fhir.rest.server.interceptor.consent;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import jakarta.annotation.Nonnull;
+import java.util.Arrays;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class IConsentVoteTest {
+
+	/** col1: stream of votes, col2: expected verdict */
+	public static final String SERIAL_STREAM_EXPECTATION = """
+		REJECT     REJECT     REJECT    , REJECT
+		REJECT     REJECT     PROCEED   , REJECT
+		REJECT     REJECT     AUTHORIZED, REJECT
+		REJECT     PROCEED    REJECT    , REJECT
+		REJECT     PROCEED    PROCEED   , REJECT
+		REJECT     PROCEED    AUTHORIZED, REJECT
+		REJECT     AUTHORIZED REJECT    , REJECT
+		REJECT     AUTHORIZED PROCEED   , REJECT
+		REJECT     AUTHORIZED AUTHORIZED, REJECT
+		PROCEED    REJECT     REJECT    , REJECT
+		PROCEED    REJECT     PROCEED   , REJECT
+		PROCEED    REJECT     AUTHORIZED, REJECT
+		PROCEED    PROCEED    REJECT    , REJECT
+		PROCEED    PROCEED    PROCEED   , PROCEED
+		PROCEED    PROCEED    AUTHORIZED, AUTHORIZED
+		PROCEED    AUTHORIZED REJECT    , AUTHORIZED
+		PROCEED    AUTHORIZED PROCEED   , AUTHORIZED
+		PROCEED    AUTHORIZED AUTHORIZED, AUTHORIZED
+		AUTHORIZED REJECT     REJECT    , AUTHORIZED
+		AUTHORIZED REJECT     PROCEED   , AUTHORIZED
+		AUTHORIZED REJECT     AUTHORIZED, AUTHORIZED
+		AUTHORIZED PROCEED    REJECT    , AUTHORIZED
+		AUTHORIZED PROCEED    PROCEED   , AUTHORIZED
+		AUTHORIZED PROCEED    AUTHORIZED, AUTHORIZED
+		AUTHORIZED AUTHORIZED REJECT    , AUTHORIZED
+		AUTHORIZED AUTHORIZED PROCEED   , AUTHORIZED
+		AUTHORIZED AUTHORIZED AUTHORIZED, AUTHORIZED
+		""";
+
+	/** col1: stream of votes, col2: expected verdict */
+	public static final String PARALLEL_STREAM_EXPECTATION = """
+		REJECT     REJECT     REJECT    , REJECT
+		REJECT     REJECT     PROCEED   , REJECT
+		REJECT     REJECT     AUTHORIZED, REJECT
+		REJECT     PROCEED    REJECT    , REJECT
+		REJECT     PROCEED    PROCEED   , REJECT
+		REJECT     PROCEED    AUTHORIZED, REJECT
+		REJECT     AUTHORIZED REJECT    , REJECT
+		REJECT     AUTHORIZED PROCEED   , REJECT
+		REJECT     AUTHORIZED AUTHORIZED, REJECT
+		PROCEED    REJECT     REJECT    , REJECT
+		PROCEED    REJECT     PROCEED   , REJECT
+		PROCEED    REJECT     AUTHORIZED, REJECT
+		PROCEED    PROCEED    REJECT    , REJECT
+		PROCEED    PROCEED    PROCEED   , PROCEED
+		PROCEED    PROCEED    AUTHORIZED, AUTHORIZED
+		PROCEED    AUTHORIZED REJECT    , REJECT
+		PROCEED    AUTHORIZED PROCEED   , AUTHORIZED
+		PROCEED    AUTHORIZED AUTHORIZED, AUTHORIZED
+		AUTHORIZED REJECT     REJECT    , REJECT
+		AUTHORIZED REJECT     PROCEED   , REJECT
+		AUTHORIZED REJECT     AUTHORIZED, REJECT
+		AUTHORIZED PROCEED    REJECT    , REJECT
+		AUTHORIZED PROCEED    PROCEED   , AUTHORIZED
+		AUTHORIZED PROCEED    AUTHORIZED, AUTHORIZED
+		AUTHORIZED AUTHORIZED REJECT    , REJECT
+		AUTHORIZED AUTHORIZED PROCEED   , AUTHORIZED
+		AUTHORIZED AUTHORIZED AUTHORIZED, AUTHORIZED
+		""";
+
+	@ParameterizedTest
+	@CsvSource(textBlock = """
+		REJECT    , REJECT    , REJECT
+		REJECT    , PROCEED   , REJECT
+		REJECT    , AUTHORIZED, REJECT
+		AUTHORIZED, REJECT    , AUTHORIZED
+		AUTHORIZED, PROCEED   , AUTHORIZED
+		AUTHORIZED, AUTHORIZED, AUTHORIZED
+		PROCEED   , REJECT    , REJECT
+		PROCEED   , PROCEED   , PROCEED
+		PROCEED   , AUTHORIZED, AUTHORIZED
+		""")
+	void testSerialReduction_choosesFirstVerdict(ConsentOperationStatusEnum theFirst, ConsentOperationStatusEnum theSecond, ConsentOperationStatusEnum theExpectedResult) {
+
+		// when
+		ConsentOperationStatusEnum result = IConsentVote.serialReduce(theFirst, theSecond);
+
+		assertEquals(theExpectedResult, result);
+	}
+
+
+	/**
+	 * With "serial" evaluation, the first non-PROCEED verdict wins.
+	 */
+	@ParameterizedTest
+	@CsvSource(textBlock = SERIAL_STREAM_EXPECTATION)
+	void testSerialStreamReduction_choosesFirstVerdict(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+		// given
+		Stream<ConsentOperationStatusEnum> consentOperationStatusEnumStream = splitEnumsToStream(theInput);
+
+		// when
+		ConsentOperationStatusEnum result = ConsentOperationStatusEnum.serialReduce(consentOperationStatusEnumStream);
+
+		assertEquals(theExpectedResult, result);
+	}
+
+	static @Nonnull Stream<ConsentOperationStatusEnum> splitEnumsToStream(String theInput) {
+		return Arrays.stream(theInput.split(" +"))
+			.map(String::trim)
+			.map(ConsentOperationStatusEnum::valueOf);
+	}
+
+
+	@ParameterizedTest
+	@CsvSource(textBlock = """
+		REJECT    , REJECT    , REJECT
+		REJECT    , PROCEED   , REJECT
+		REJECT    , AUTHORIZED, REJECT
+		AUTHORIZED, REJECT    , REJECT
+		AUTHORIZED, PROCEED   , AUTHORIZED
+		AUTHORIZED, AUTHORIZED, AUTHORIZED
+		PROCEED   , REJECT    , REJECT
+		PROCEED   , PROCEED   , PROCEED
+		PROCEED   , AUTHORIZED, AUTHORIZED
+		""")
+	void testParallelReduction_choosesStrongestVerdict(ConsentOperationStatusEnum theFirst, ConsentOperationStatusEnum theSecond, ConsentOperationStatusEnum theExpectedResult) {
+
+		// when
+		ConsentOperationStatusEnum result = IConsentVote.parallelReduce(theFirst, theSecond);
+
+		assertEquals(theExpectedResult, result);
+	}
+
+
+	/**
+	 * With "parallel" evaluation, the "strongest" verdict wins.
+	 * REJECT > AUTHORIZED > PROCEED.
+	 */
+	@ParameterizedTest
+	@CsvSource(textBlock = PARALLEL_STREAM_EXPECTATION)
+	void testParallelStreamReduction_strongestVerdictWins(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+		// given
+		Stream<ConsentOperationStatusEnum> consentOperationStatusEnumStream = splitEnumsToStream(theInput);
+
+		// when
+		ConsentOperationStatusEnum result = ConsentOperationStatusEnum.parallelReduce(consentOperationStatusEnumStream);
+
+		assertEquals(theExpectedResult, result);
+	}
+
+}

hapi-fhir-server/src/test/java/ca/uhn/fhir/rest/server/interceptor/consent/MultiDelegateConsentServiceTest.java

@@ -0,0 +1,166 @@
+package ca.uhn.fhir.rest.server.interceptor.consent;
+
+import ca.uhn.fhir.rest.api.server.RequestDetails;
+import ca.uhn.fhir.rest.api.server.SystemRequestDetails;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import jakarta.annotation.Nonnull;
+import java.util.Arrays;
+import java.util.List;
+
+import static ca.uhn.fhir.rest.server.interceptor.consent.MultiDelegateConsentService.withParallelVoting;
+import static ca.uhn.fhir.rest.server.interceptor.consent.MultiDelegateConsentService.withSerialVoting;
+import static ca.uhn.fhir.rest.server.interceptor.consent.IConsentVoteTest.PARALLEL_STREAM_EXPECTATION;
+import static ca.uhn.fhir.rest.server.interceptor.consent.IConsentVoteTest.SERIAL_STREAM_EXPECTATION;
+import static ca.uhn.fhir.rest.server.interceptor.consent.IConsentVoteTest.splitEnumsToStream;
+import static org.apache.commons.lang3.StringUtils.defaultString;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class MultiDelegateConsentServiceTest {
+	SystemRequestDetails mySrd = new SystemRequestDetails();
+
+	/**
+	 * "parallel" means any voter can veto.
+	 */
+	@Nested
+	class ParallelEvaluation {
+		MultiDelegateConsentService myService;
+
+		@ParameterizedTest
+		@CsvSource(textBlock = PARALLEL_STREAM_EXPECTATION)
+		void testStartOperation(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+
+			var services = splitEnumsToStream(theInput).map(result -> (IConsentService)ConstantConsentService.constantService(result)).toList();
+			myService = withParallelVoting(services);
+
+			var verdict = myService.startOperation(mySrd, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult.getStatus(), verdict.getStatus());
+		}
+
+
+		@ParameterizedTest
+		@CsvSource(textBlock = """
+						, false
+			true		, true
+			false		, false
+			false true	, true
+			true false	, true
+			""")
+		void testCanSeeResource(String theInput, boolean theExpectedResult) {
+
+			List<IConsentService> consentServices = Arrays.stream(defaultString(theInput).split(" +"))
+				.map(String::trim)
+				.map(Boolean::valueOf)
+				.map(MultiDelegateConsentServiceTest::buildConsentShouldProcessCanSee)
+				.toList();
+			myService = withParallelVoting(consentServices);
+
+			var result = myService.shouldProcessCanSeeResource(mySrd, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult, result);
+		}
+
+		@ParameterizedTest
+		@CsvSource(textBlock = PARALLEL_STREAM_EXPECTATION)
+		void testCanSeeResource(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+
+			var services = splitEnumsToStream(theInput).map(result -> (IConsentService)ConstantConsentService.constantService(result)).toList();
+			myService = withParallelVoting(services);
+
+			var verdict = myService.canSeeResource(mySrd, null, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult.getStatus(), verdict.getStatus());
+		}
+
+		@ParameterizedTest
+		@CsvSource(textBlock = PARALLEL_STREAM_EXPECTATION)
+		void testWillSeeResource(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+
+			var services = splitEnumsToStream(theInput).map(result -> (IConsentService)ConstantConsentService.constantService(result)).toList();
+			myService = withParallelVoting(services);
+
+			var verdict = myService.willSeeResource(mySrd, null, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult.getStatus(), verdict.getStatus());
+		}
+	}
+
+	/**
+	 * "serial" means first comited vote wins
+	 */
+	@Nested
+	class SerialEvaluation {
+		MultiDelegateConsentService myService;
+
+		@ParameterizedTest
+		@CsvSource(textBlock = SERIAL_STREAM_EXPECTATION)
+		void testStartOperation(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+
+			var services = splitEnumsToStream(theInput).map(result -> (IConsentService)ConstantConsentService.constantService(result)).toList();
+			myService = withSerialVoting(services);
+
+			var verdict = myService.startOperation(mySrd, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult.getStatus(), verdict.getStatus());
+		}
+
+		@ParameterizedTest
+		@CsvSource(textBlock = """
+						, false
+			true		, true
+			false		, false
+			false true	, true
+			true false	, true
+			""")
+		void testCanSeeResource(String theInput, boolean theExpectedResult) {
+
+			List<IConsentService> consentServices = Arrays.stream(defaultString(theInput).split(" +"))
+				.map(String::trim)
+				.map(Boolean::valueOf)
+				.map(MultiDelegateConsentServiceTest::buildConsentShouldProcessCanSee)
+				.toList();
+			myService = withSerialVoting(consentServices);
+
+			var result = myService.shouldProcessCanSeeResource(mySrd, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult, result);
+		}
+
+		@ParameterizedTest
+		@CsvSource(textBlock = SERIAL_STREAM_EXPECTATION)
+		void testCanSeeResource(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+
+			var services = splitEnumsToStream(theInput).map(result -> (IConsentService)ConstantConsentService.constantService(result)).toList();
+			myService = withSerialVoting(services);
+
+			var verdict = myService.canSeeResource(mySrd, null, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult.getStatus(), verdict.getStatus());
+		}
+
+		@ParameterizedTest
+		@CsvSource(textBlock = SERIAL_STREAM_EXPECTATION)
+		void testWillSeeResource(String theInput, ConsentOperationStatusEnum theExpectedResult) {
+
+			var services = splitEnumsToStream(theInput).map(result -> (IConsentService)ConstantConsentService.constantService(result)).toList();
+			myService = withSerialVoting(services);
+
+			var verdict = myService.willSeeResource(mySrd, null, IConsentContextServices.NULL_IMPL);
+
+			assertEquals(theExpectedResult.getStatus(), verdict.getStatus());
+		}
+	}
+
+	private static @Nonnull IConsentService buildConsentShouldProcessCanSee(boolean result) {
+		return new IConsentService() {
+			@Override
+			public boolean shouldProcessCanSeeResource(RequestDetails theRequestDetails, IConsentContextServices theContextServices) {
+				return result;
+			}
+		};
+	}
+
+}