Slightly more portable solution for paging

hapi-fhir-jpaserver-mdm/src/main/java/ca/uhn/fhir/jpa/mdm/dao/MdmLinkDaoSvc.java

@@ -27,6 +27,7 @@ import ca.uhn.fhir.jpa.entity.MdmLink;
 import ca.uhn.fhir.mdm.api.MdmLinkSourceEnum;
 import ca.uhn.fhir.mdm.api.MdmMatchOutcome;
 import ca.uhn.fhir.mdm.api.MdmMatchResultEnum;
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.log.Logs;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import org.hl7.fhir.instance.model.api.IBaseResource;
@@ -34,8 +35,6 @@ import org.slf4j.Logger;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Example;
 import org.springframework.data.domain.Page;
-import org.springframework.data.domain.PageRequest;
-import org.springframework.data.domain.Pageable;
 import org.springframework.transaction.annotation.Propagation;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -289,9 +288,8 @@ public class MdmLinkDaoSvc {
 	 * @param theExampleLink The MDM link containing the data we would like to search for.
 	 * @return a list of {@link MdmLink} entities which match the example.
 	 */
-	public Page<MdmLink> findMdmLinkByExample(Example<MdmLink> theExampleLink, int theOffset, int theCount) {
+	public Page<MdmLink> findMdmLinkByExample(Example<MdmLink> theExampleLink, MdmPageRequest thePageRequest) {
-		PageRequest of = PageRequest.of(theOffset / theCount, theCount);
+		return myMdmLinkDao.findAll(theExampleLink, thePageRequest.toPageRequest());
-		return myMdmLinkDao.findAll(theExampleLink, of);
 	}
 
 	/**

hapi-fhir-jpaserver-mdm/src/main/java/ca/uhn/fhir/jpa/mdm/svc/MdmControllerSvcImpl.java

@@ -27,6 +27,7 @@ import ca.uhn.fhir.mdm.api.IMdmLinkUpdaterSvc;
 import ca.uhn.fhir.mdm.api.MdmLinkJson;
 import ca.uhn.fhir.mdm.api.MdmLinkSourceEnum;
 import ca.uhn.fhir.mdm.api.MdmMatchResultEnum;
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import ca.uhn.fhir.mdm.provider.MdmControllerHelper;
 import ca.uhn.fhir.mdm.provider.MdmControllerUtil;
@@ -34,10 +35,10 @@ import ca.uhn.fhir.rest.server.provider.ProviderConstants;
 import org.hl7.fhir.instance.model.api.IAnyResource;
 import org.hl7.fhir.instance.model.api.IIdType;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
 import org.springframework.stereotype.Service;
 
 import javax.annotation.Nullable;
-import java.util.stream.Stream;
 
 /**
  * This class acts as a layer between MdmProviders and MDM services to support a REST API that's not a FHIR Operation API.
@@ -66,17 +67,17 @@ public class MdmControllerSvcImpl implements IMdmControllerSvc {
 	}
 
 	@Override
-	public Stream<MdmLinkJson> queryLinks(@Nullable String theGoldenResourceId, @Nullable String theSourceResourceId, @Nullable String theMatchResult, @Nullable String theLinkSource, MdmTransactionContext theMdmTransactionContext, int theOffset, int theCount) {
+	public Page<MdmLinkJson> queryLinks(@Nullable String theGoldenResourceId, @Nullable String theSourceResourceId, @Nullable String theMatchResult, @Nullable String theLinkSource, MdmTransactionContext theMdmTransactionContext, MdmPageRequest thePageRequest) {
 		IIdType goldenResourceId = MdmControllerUtil.extractGoldenResourceIdDtOrNull(ProviderConstants.MDM_QUERY_LINKS_GOLDEN_RESOURCE_ID, theGoldenResourceId);
 		IIdType sourceId = MdmControllerUtil.extractSourceIdDtOrNull(ProviderConstants.MDM_QUERY_LINKS_RESOURCE_ID, theSourceResourceId);
 		MdmMatchResultEnum matchResult = MdmControllerUtil.extractMatchResultOrNull(theMatchResult);
 		MdmLinkSourceEnum linkSource = MdmControllerUtil.extractLinkSourceOrNull(theLinkSource);
-		return myMdmLinkQuerySvc.queryLinks(goldenResourceId, sourceId, matchResult, linkSource, theMdmTransactionContext, theOffset, theCount);
+		return myMdmLinkQuerySvc.queryLinks(goldenResourceId, sourceId, matchResult, linkSource, theMdmTransactionContext, thePageRequest);
 	}
 
 	@Override
-	public Stream<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmTransactionContext, int theOffset, int theCount) {
+	public Page<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmTransactionContext, MdmPageRequest thePageRequest) {
-		return myMdmLinkQuerySvc.getDuplicateGoldenResources(theMdmTransactionContext, theOffset, theCount);
+		return myMdmLinkQuerySvc.getDuplicateGoldenResources(theMdmTransactionContext, thePageRequest);
 	}
 
 	@Override

hapi-fhir-jpaserver-mdm/src/main/java/ca/uhn/fhir/jpa/mdm/svc/MdmLinkQuerySvcImpl.java

@@ -24,6 +24,7 @@ import ca.uhn.fhir.mdm.api.MdmLinkJson;
 import ca.uhn.fhir.mdm.api.MdmLinkSourceEnum;
 import ca.uhn.fhir.mdm.api.MdmMatchResultEnum;
 import ca.uhn.fhir.mdm.api.IMdmLinkQuerySvc;
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import ca.uhn.fhir.jpa.dao.index.IdHelperService;
 import ca.uhn.fhir.jpa.mdm.dao.MdmLinkDaoSvc;
@@ -35,8 +36,6 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Example;
 import org.springframework.data.domain.Page;
 
-import java.util.stream.Stream;
-
 public class MdmLinkQuerySvcImpl implements IMdmLinkQuerySvc {
 
 	private static final Logger ourLog = LoggerFactory.getLogger(MdmLinkQuerySvcImpl.class);
@@ -47,16 +46,19 @@ public class MdmLinkQuerySvcImpl implements IMdmLinkQuerySvc {
 	MdmLinkDaoSvc myMdmLinkDaoSvc;
 
 	@Override
-	public Stream<MdmLinkJson> queryLinks(IIdType theGoldenResourceId, IIdType theSourceResourceId, MdmMatchResultEnum theMatchResult, MdmLinkSourceEnum theLinkSource, MdmTransactionContext theMdmContext, int theOffset, int theCount) {
+	public Page<MdmLinkJson> queryLinks(IIdType theGoldenResourceId, IIdType theSourceResourceId, MdmMatchResultEnum theMatchResult, MdmLinkSourceEnum theLinkSource, MdmTransactionContext theMdmContext, MdmPageRequest thePageRequest) {
 		Example<MdmLink> exampleLink = exampleLinkFromParameters(theGoldenResourceId, theSourceResourceId, theMatchResult, theLinkSource);
-		Page<MdmLink> mdmLinkByExample = myMdmLinkDaoSvc.findMdmLinkByExample(exampleLink, theOffset, theCount);
+		Page<MdmLink> mdmLinkByExample = myMdmLinkDaoSvc.findMdmLinkByExample(exampleLink, thePageRequest);
-		return mdmLinkByExample.stream().map(this::toJson);
+		Page<MdmLinkJson> map = mdmLinkByExample.map(this::toJson);
+		return map;
 	}
 
 	@Override
-	public Stream<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmContext, int theOffset, int theCount) {
+	public Page<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmContext, MdmPageRequest thePageRequest) {
 		Example<MdmLink> exampleLink = exampleLinkFromParameters(null, null, MdmMatchResultEnum.POSSIBLE_DUPLICATE, null);
-		return myMdmLinkDaoSvc.findMdmLinkByExample(exampleLink, theOffset, theCount).stream().map(this::toJson);
+		Page<MdmLink> mdmLinkPage = myMdmLinkDaoSvc.findMdmLinkByExample(exampleLink, thePageRequest);
+		Page<MdmLinkJson> map = mdmLinkPage.map(this::toJson);
+		return map;
 	}
 
 	private MdmLinkJson toJson(MdmLink theLink) {

hapi-fhir-jpaserver-mdm/src/test/java/ca/uhn/fhir/jpa/mdm/provider/BaseProviderR4Test.java

@@ -7,6 +7,7 @@ import ca.uhn.fhir.mdm.api.IMdmMatchFinderSvc;
 import ca.uhn.fhir.mdm.api.IMdmSubmitSvc;
 import ca.uhn.fhir.mdm.provider.MdmProviderDstu3Plus;
 import ca.uhn.fhir.mdm.rules.config.MdmSettings;
+import ca.uhn.fhir.rest.server.IRestfulServerDefaults;
 import com.google.common.base.Charsets;
 import org.apache.commons.io.IOUtils;
 import org.junit.jupiter.api.AfterEach;
@@ -29,6 +30,8 @@ public abstract class BaseProviderR4Test extends BaseMdmR4Test {
 	private IMdmSubmitSvc myMdmSubmitSvc;
 	@Autowired
 	private MdmSettings myMdmSettings;
+	@Autowired
+	private IRestfulServerDefaults myRestfulServerDefaults;
 
 	private String defaultScript;
 
@@ -42,7 +45,7 @@ public abstract class BaseProviderR4Test extends BaseMdmR4Test {
 
 	@BeforeEach
 	public void before() {
-		myMdmProvider = new MdmProviderDstu3Plus(myFhirContext, myMdmControllerSvc, myMdmMatchFinderSvc, myMdmExpungeSvc, myMdmSubmitSvc);
+		myMdmProvider = new MdmProviderDstu3Plus(myFhirContext, myMdmControllerSvc, myMdmMatchFinderSvc, myMdmExpungeSvc, myMdmSubmitSvc, myRestfulServerDefaults);
 		defaultScript = myMdmSettings.getScriptText();
 	}
 	@AfterEach

hapi-fhir-jpaserver-mdm/src/test/java/ca/uhn/fhir/jpa/mdm/provider/MdmProviderQueryLinkR4Test.java

@@ -90,7 +90,7 @@ public class MdmProviderQueryLinkR4Test extends BaseLinkR4Test {
 			ourLog.warn("Search at offset {} took {}ms",offset, sw.getMillisAndRestart());
 			ourLog.warn("Found source resource IDs: {}", sourceResourceIds);
 			offset += count;
-			assertThat(parameter.size(), is(lessThanOrEqualTo(2)));
+			assertThat(parameter.size(), is(lessThanOrEqualTo(3)));
 
 			//We have stopped finding patients.
 			if (StringUtils.isEmpty(sourceResourceIds)) {

hapi-fhir-server-mdm/pom.xml

@@ -27,6 +27,11 @@
 			<artifactId>hapi-fhir-server</artifactId>
 			<version>${project.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.data</groupId>
+			<artifactId>spring-data-commons</artifactId>
+			<version>${spring_data_version}</version>
+		</dependency>
 		<dependency>
 			<groupId>ca.uhn.hapi.fhir</groupId>
 			<artifactId>hapi-fhir-structures-dstu3</artifactId>

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/api/IMdmControllerSvc.java

@@ -20,17 +20,18 @@ package ca.uhn.fhir.mdm.api;
  * #L%
  */
 
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import org.hl7.fhir.instance.model.api.IAnyResource;
+import org.springframework.data.domain.Page;
 
 import javax.annotation.Nullable;
-import java.util.stream.Stream;
 
 public interface IMdmControllerSvc {
 
-	Stream<MdmLinkJson> queryLinks(@Nullable String theGoldenResourceId, @Nullable String theSourceResourceId, @Nullable String theMatchResult, @Nullable String theLinkSource, MdmTransactionContext theMdmTransactionContext, int theOffset, int theCount);
+	Page<MdmLinkJson> queryLinks(@Nullable String theGoldenResourceId, @Nullable String theSourceResourceId, @Nullable String theMatchResult, @Nullable String theLinkSource, MdmTransactionContext theMdmTransactionContext, MdmPageRequest thePageRequest);
 
-	Stream<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmTransactionContext, int theOffset, int theCount);
+	Page<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmTransactionContext, MdmPageRequest thePageRequest);
 
 	void notDuplicateGoldenResource(String theGoldenResourceId, String theTargetGoldenResourceId, MdmTransactionContext theMdmTransactionContext);
 

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/api/IMdmLinkQuerySvc.java

@@ -20,15 +20,15 @@ package ca.uhn.fhir.mdm.api;
  * #L%
  */
 
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import org.hl7.fhir.instance.model.api.IIdType;
-
+import org.springframework.data.domain.Page;
-import java.util.stream.Stream;
 
 /**
  * This service supports the MDM operation providers for those services that return multiple MDM links.
  */
 public interface IMdmLinkQuerySvc {
-	Stream<MdmLinkJson> queryLinks(IIdType theGoldenResourceId, IIdType theSourceResourceId, MdmMatchResultEnum theMatchResult, MdmLinkSourceEnum theLinkSource, MdmTransactionContext theMdmContext, int theOffset, int theCount);
+	Page<MdmLinkJson> queryLinks(IIdType theGoldenResourceId, IIdType theSourceResourceId, MdmMatchResultEnum theMatchResult, MdmLinkSourceEnum theLinkSource, MdmTransactionContext theMdmContext, MdmPageRequest thePageRequest);
-	Stream<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmContext, int theOffset, int theCount);
+	Page<MdmLinkJson> getDuplicateGoldenResources(MdmTransactionContext theMdmContext, MdmPageRequest thePageRequest);
 }

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/api/paging/MdmPageLinkBuilder.java

@@ -0,0 +1,38 @@
+package ca.uhn.fhir.mdm.api.paging;
+
+import ca.uhn.fhir.mdm.api.MdmLinkJson;
+import ca.uhn.fhir.rest.server.RestfulServerUtils;
+import ca.uhn.fhir.rest.server.servlet.ServletRequestDetails;
+import ca.uhn.fhir.util.ParametersUtil;
+import org.springframework.data.domain.Page;
+
+import java.util.Arrays;
+
+import static ca.uhn.fhir.rest.api.Constants.PARAM_COUNT;
+import static ca.uhn.fhir.rest.api.Constants.PARAM_OFFSET;
+
+public final class MdmPageLinkBuilder {
+	public static MdmPageLinkTuple buildMdmPageLinks(ServletRequestDetails theServletRequestDetails, Page<MdmLinkJson> theCurrentPage, MdmPageRequest thePageRequest) {
+		MdmPageLinkTuple tuple = new MdmPageLinkTuple();
+		String urlWithoutPaging = RestfulServerUtils.createLinkSelfWithoutGivenParameters(theServletRequestDetails.getFhirServerBase(), theServletRequestDetails, Arrays.asList(PARAM_OFFSET, PARAM_COUNT));
+		tuple.setSelfLink(buildLinkWithOffsetAndCount(urlWithoutPaging, thePageRequest.getCount(), thePageRequest.getOffset()));
+		if (theCurrentPage.hasNext()) {
+			tuple.setNextLink(buildLinkWithOffsetAndCount(urlWithoutPaging,thePageRequest.getCount(), thePageRequest.getNextOffset()));
+		}
+		if (theCurrentPage.hasPrevious()) {
+			tuple.setPreviousLink(buildLinkWithOffsetAndCount(urlWithoutPaging,thePageRequest.getCount(), thePageRequest.getPreviousOffset()));
+		}
+		return tuple;
+
+	}
+	protected static String buildLinkWithOffsetAndCount(String theStartingUrl, int theCount, int theOffset) {
+		StringBuilder builder = new StringBuilder();
+		builder.append(theStartingUrl);
+		if (!theStartingUrl.contains("?")) {
+			builder.append("?");
+		}
+		builder.append(PARAM_OFFSET).append("=").append(theOffset);
+		builder.append(PARAM_COUNT).append("=").append(theCount);
+		return builder.toString();
+	}
+}

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/api/paging/MdmPageLinkTuple.java

@@ -0,0 +1,36 @@
+package ca.uhn.fhir.mdm.api.paging;
+
+import java.util.Optional;
+
+public class MdmPageLinkTuple {
+	private String myPreviousLink = null;
+	private String mySelfLink = null;
+	private String myNextLink = null;
+
+	MdmPageLinkTuple() {
+	}
+
+	public Optional<String> getPreviousLink() {
+		return Optional.ofNullable(myPreviousLink);
+	}
+
+	public void setPreviousLink(String thePreviousLink) {
+		this.myPreviousLink = thePreviousLink;
+	}
+
+	public String getSelfLink() {
+		return mySelfLink;
+	}
+
+	public void setSelfLink(String theSelfLink) {
+		this.mySelfLink = theSelfLink;
+	}
+
+	public Optional<String> getNextLink() {
+		return Optional.ofNullable(myNextLink);
+	}
+
+	public void setNextLink(String theNextLink) {
+		this.myNextLink = theNextLink;
+	}
+}

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/api/paging/MdmPageRequest.java

@@ -0,0 +1,69 @@
+package ca.uhn.fhir.mdm.api.paging;
+
+import ca.uhn.fhir.rest.server.IRestfulServerDefaults;
+import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
+import org.apache.commons.lang3.StringUtils;
+import org.hl7.fhir.dstu3.model.UnsignedIntType;
+import org.slf4j.Logger;
+import org.springframework.data.domain.PageRequest;
+
+import static ca.uhn.fhir.rest.api.Constants.PARAM_COUNT;
+import static ca.uhn.fhir.rest.api.Constants.PARAM_OFFSET;
+import static org.slf4j.LoggerFactory.getLogger;
+
+public class MdmPageRequest {
+	private static final Logger ourLog = getLogger(MdmPageRequest.class);
+
+	private int myPage;
+	private int myOffset;
+	private int myCount;
+	private IRestfulServerDefaults myRestfulServerDefaults;
+
+	public MdmPageRequest(UnsignedIntType theOffset, UnsignedIntType theCount, IRestfulServerDefaults theDefaults) {
+		myOffset = theOffset == null ? 0 : theOffset.getValue();
+		myCount = theCount == null ? theDefaults.getDefaultPageSize() : theCount.getValue();
+		validatePagingParameters(myOffset, myCount);
+
+		this.myPage = myOffset / myCount;
+	}
+
+	public PageRequest toPageRequest() {
+		return PageRequest.of(this.myPage, this.myCount);
+	}
+
+	private void validatePagingParameters(int theOffset, int theCount) {
+		String errorMessage = "";
+
+		if (theOffset < 0) {
+			errorMessage += PARAM_OFFSET + " must be greater than or equal to 0. ";
+		}
+		if (theCount <= 0 ) {
+			errorMessage += PARAM_COUNT + " must be greater than 0.";
+		}
+		if (myRestfulServerDefaults.getMaximumPageSize() != null && theCount > myRestfulServerDefaults.getMaximumPageSize() ) {
+			ourLog.debug("Shrinking page size down to {}, as this is the maximum allowed.", myRestfulServerDefaults.getMaximumPageSize());
+		}
+		if (StringUtils.isNotEmpty(errorMessage)) {
+			throw new InvalidRequestException(errorMessage);
+		}
+	}
+
+	public int getOffset() {
+		return myOffset;
+	}
+
+	public int getPage() {
+		return myPage;
+	}
+
+	public int getCount() {
+		return myCount;
+	}
+
+	public int getNextOffset() {
+		return myOffset + myCount;
+	}
+	public int getPreviousOffset() {
+		return myOffset - myCount;
+	}
+}

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/provider/BaseMdmProvider.java

@@ -23,17 +23,26 @@ package ca.uhn.fhir.mdm.provider;
 import ca.uhn.fhir.context.FhirContext;
 import ca.uhn.fhir.mdm.api.MdmLinkJson;
 import ca.uhn.fhir.mdm.api.MdmMatchResultEnum;
+import ca.uhn.fhir.mdm.api.paging.MdmPageLinkBuilder;
+import ca.uhn.fhir.mdm.api.paging.MdmPageLinkTuple;
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import ca.uhn.fhir.rest.api.server.RequestDetails;
+import ca.uhn.fhir.rest.server.RestfulServerUtils;
 import ca.uhn.fhir.rest.server.TransactionLogMessages;
 import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
 import ca.uhn.fhir.rest.server.provider.ProviderConstants;
+import ca.uhn.fhir.rest.server.servlet.ServletRequestDetails;
 import ca.uhn.fhir.util.ParametersUtil;
 import org.hl7.fhir.instance.model.api.IBase;
 import org.hl7.fhir.instance.model.api.IBaseParameters;
 import org.hl7.fhir.instance.model.api.IPrimitiveType;
+import org.springframework.data.domain.Page;
 
-import java.util.stream.Stream;
+import java.util.Arrays;
+
+import static ca.uhn.fhir.rest.api.Constants.PARAM_COUNT;
+import static ca.uhn.fhir.rest.api.Constants.PARAM_OFFSET;
 
 public abstract class BaseMdmProvider {
 
@@ -92,9 +101,9 @@ public abstract class BaseMdmProvider {
 		return theString.getValue();
 	}
 
-	protected IBaseParameters parametersFromMdmLinks(Stream<MdmLinkJson> theMdmLinkStream, boolean includeResultAndSource) {
+	protected IBaseParameters parametersFromMdmLinks(Page<MdmLinkJson> theMdmLinkStream, boolean includeResultAndSource, ServletRequestDetails theServletRequestDetails, MdmPageRequest thePageRequest) {
 		IBaseParameters retval = ParametersUtil.newInstance(myFhirContext);
-
+		addPagingParameters(retval, theMdmLinkStream, theServletRequestDetails, thePageRequest);
 		theMdmLinkStream.forEach(mdmLink -> {
 			IBase resultPart = ParametersUtil.addParameterToParameters(myFhirContext, retval, "link");
 			ParametersUtil.addPartString(myFhirContext, resultPart, "goldenResourceId", mdmLink.getGoldenResourceId());
@@ -111,4 +120,15 @@ public abstract class BaseMdmProvider {
 		return retval;
 	}
 
+	protected void addPagingParameters(IBaseParameters theParameters, Page<MdmLinkJson> theCurrentPage, ServletRequestDetails theServletRequestDetails, MdmPageRequest thePageRequest) {
+		MdmPageLinkTuple mdmPageLinkTuple = MdmPageLinkBuilder.buildMdmPageLinks(theServletRequestDetails, theCurrentPage, thePageRequest);
+		ParametersUtil.addParameterToParametersUri(myFhirContext, theParameters, "self", mdmPageLinkTuple.getSelfLink());
+
+		if (mdmPageLinkTuple.getNextLink().isPresent()) {
+			ParametersUtil.addParameterToParametersUri(myFhirContext, theParameters, "next", mdmPageLinkTuple.getNextLink().get());
+		}
+		if (mdmPageLinkTuple.getPreviousLink().isPresent()) {
+			ParametersUtil.addParameterToParametersUri(myFhirContext, theParameters, "prev", mdmPageLinkTuple.getPreviousLink().get());
+		}
+	}
 }

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/provider/MdmProviderDstu3Plus.java

@@ -28,6 +28,7 @@ import ca.uhn.fhir.mdm.api.IMdmSubmitSvc;
 import ca.uhn.fhir.mdm.api.MatchedTarget;
 import ca.uhn.fhir.mdm.api.MdmConstants;
 import ca.uhn.fhir.mdm.api.MdmLinkJson;
+import ca.uhn.fhir.mdm.api.paging.MdmPageRequest;
 import ca.uhn.fhir.mdm.model.MdmTransactionContext;
 import ca.uhn.fhir.model.api.annotation.Description;
 import ca.uhn.fhir.rest.annotation.IdParam;
@@ -35,6 +36,7 @@ import ca.uhn.fhir.rest.annotation.Operation;
 import ca.uhn.fhir.rest.annotation.OperationParam;
 import ca.uhn.fhir.rest.api.Constants;
 import ca.uhn.fhir.rest.api.server.RequestDetails;
+import ca.uhn.fhir.rest.server.IRestfulServerDefaults;
 import ca.uhn.fhir.rest.server.exceptions.InvalidRequestException;
 import ca.uhn.fhir.rest.server.provider.ProviderConstants;
 import ca.uhn.fhir.rest.server.servlet.ServletRequestDetails;
@@ -52,6 +54,8 @@ import org.hl7.fhir.instance.model.api.IBaseParameters;
 import org.hl7.fhir.instance.model.api.IBaseResource;
 import org.hl7.fhir.instance.model.api.IIdType;
 import org.hl7.fhir.instance.model.api.IPrimitiveType;
+import org.slf4j.Logger;
+import org.springframework.data.domain.Page;
 
 import javax.annotation.Nonnull;
 import java.math.BigDecimal;
@@ -59,17 +63,19 @@ import java.util.Comparator;
 import java.util.Date;
 import java.util.List;
 import java.util.UUID;
-import java.util.stream.Stream;
 
-import static ca.uhn.fhir.rest.api.Constants.PARAM_COUNT;
 import static ca.uhn.fhir.rest.api.Constants.PARAM_OFFSET;
+import static org.slf4j.LoggerFactory.getLogger;
 
 public class MdmProviderDstu3Plus extends BaseMdmProvider {
+	private static final Logger ourLog = getLogger(MdmProviderDstu3Plus.class);
+
 
 	private final IMdmControllerSvc myMdmControllerSvc;
 	private final IMdmMatchFinderSvc myMdmMatchFinderSvc;
 	private final IMdmExpungeSvc myMdmExpungeSvc;
 	private final IMdmSubmitSvc myMdmSubmitSvc;
+	private final IRestfulServerDefaults myRestfulServerDefaults;
 
 	/**
 	 * Constructor
@@ -77,12 +83,13 @@ public class MdmProviderDstu3Plus extends BaseMdmProvider {
 	 * Note that this is not a spring bean. Any necessary injections should
 	 * happen in the constructor
 	 */
-	public MdmProviderDstu3Plus(FhirContext theFhirContext, IMdmControllerSvc theMdmControllerSvc, IMdmMatchFinderSvc theMdmMatchFinderSvc, IMdmExpungeSvc theMdmExpungeSvc, IMdmSubmitSvc theMdmSubmitSvc) {
+	public MdmProviderDstu3Plus(FhirContext theFhirContext, IMdmControllerSvc theMdmControllerSvc, IMdmMatchFinderSvc theMdmMatchFinderSvc, IMdmExpungeSvc theMdmExpungeSvc, IMdmSubmitSvc theMdmSubmitSvc, IRestfulServerDefaults theRestfulServerDefaults) {
 		super(theFhirContext);
 		myMdmControllerSvc = theMdmControllerSvc;
 		myMdmMatchFinderSvc = theMdmMatchFinderSvc;
 		myMdmExpungeSvc = theMdmExpungeSvc;
 		myMdmSubmitSvc = theMdmSubmitSvc;
+		myRestfulServerDefaults = theRestfulServerDefaults;
 	}
 
 	@Operation(name = ProviderConstants.EMPI_MATCH, typeName = "Patient")
@@ -199,40 +206,38 @@ public class MdmProviderDstu3Plus extends BaseMdmProvider {
 														 IPrimitiveType<String> theLinkSource,
 
 												 @Description(formalDefinition="Results from this method are returned across multiple pages. This parameter controls the offset when fetching a page.")
-												 @OperationParam(name = PARAM_OFFSET)
+												 @OperationParam(name = PARAM_OFFSET, min = 0, max = 1)
 														 UnsignedIntType theOffset,
 												 @Description(formalDefinition = "Results from this method are returned across multiple pages. This parameter controls the size of those pages.")
-												 @OperationParam(name = Constants.PARAM_COUNT)
+												 @OperationParam(name = Constants.PARAM_COUNT, min = 0, max = 1)
 														 UnsignedIntType theCount,
 
 												 ServletRequestDetails theRequestDetails) {
-		validatePagingParameters(theOffset, theCount);
+		MdmPageRequest mdmPageRequest = new MdmPageRequest(theOffset, theCount, myRestfulServerDefaults);
-
+		Page<MdmLinkJson> mdmLinkJson = myMdmControllerSvc.queryLinks(extractStringOrNull(theGoldenResourceId),
-		Stream<MdmLinkJson> mdmLinkJson = myMdmControllerSvc.queryLinks(extractStringOrNull(theGoldenResourceId),
 			extractStringOrNull(theResourceId), extractStringOrNull(theMatchResult), extractStringOrNull(theLinkSource),
 			createMdmContext(theRequestDetails, MdmTransactionContext.OperationType.QUERY_LINKS,
-				getResourceType(ProviderConstants.MDM_QUERY_LINKS_GOLDEN_RESOURCE_ID, theGoldenResourceId)), theOffset.getValue(), theCount.getValue()
+				getResourceType(ProviderConstants.MDM_QUERY_LINKS_GOLDEN_RESOURCE_ID, theGoldenResourceId)), mdmPageRequest);
-		);
+
-		return parametersFromMdmLinks(mdmLinkJson, true);
+		return parametersFromMdmLinks(mdmLinkJson, true, theRequestDetails, mdmPageRequest);
 	}
 
-	private void validatePagingParameters(UnsignedIntType theOffset, UnsignedIntType theCount) {
-		String errorMessage = "";
-		if (theOffset!= null && theOffset.getValue() < 0) {
-				errorMessage += PARAM_OFFSET + " must be greater than or equal to 0. ";
-		}
-		if (theCount != null && theCount.getValue() <= 0 ) {
-			errorMessage += PARAM_COUNT + " must be greater than 0.";
-		}
-		if (StringUtils.isNotEmpty(errorMessage)) {
-			throw new InvalidRequestException(errorMessage);
-		}
-	}
 
 	@Operation(name = ProviderConstants.MDM_DUPLICATE_GOLDEN_RESOURCES, idempotent = true)
-	public IBaseParameters getDuplicateGoldenResources(ServletRequestDetails theRequestDetails) {
+	public IBaseParameters getDuplicateGoldenResources(
-		Stream<MdmLinkJson> possibleDuplicates = myMdmControllerSvc.getDuplicateGoldenResources(createMdmContext(theRequestDetails, MdmTransactionContext.OperationType.DUPLICATE_GOLDEN_RESOURCES, (String) null),0,10);
+		@Description(formalDefinition="Results from this method are returned across multiple pages. This parameter controls the offset when fetching a page.")
-		return parametersFromMdmLinks(possibleDuplicates, false);
+		@OperationParam(name = PARAM_OFFSET, min = 0, max = 1)
+			UnsignedIntType theOffset,
+		@Description(formalDefinition = "Results from this method are returned across multiple pages. This parameter controls the size of those pages.")
+		@OperationParam(name = Constants.PARAM_COUNT, min = 0, max = 1)
+			UnsignedIntType theCount,
+		ServletRequestDetails theRequestDetails) {
+
+		MdmPageRequest mdmPageRequest = new MdmPageRequest(theOffset, theCount, myRestfulServerDefaults);
+
+		Page<MdmLinkJson> possibleDuplicates = myMdmControllerSvc.getDuplicateGoldenResources(createMdmContext(theRequestDetails, MdmTransactionContext.OperationType.DUPLICATE_GOLDEN_RESOURCES, (String) null), mdmPageRequest);
+
+		return parametersFromMdmLinks(possibleDuplicates, false, theRequestDetails, mdmPageRequest);
 	}
 
 	@Operation(name = ProviderConstants.MDM_NOT_DUPLICATE)
@@ -260,7 +265,6 @@ public class MdmProviderDstu3Plus extends BaseMdmProvider {
 		ServletRequestDetails theRequestDetails) {
 		String criteria = convertStringTypeToString(theCriteria);
 		String resourceType = convertStringTypeToString(theResourceType);
-
 		long submittedCount;
 		if (resourceType != null) {
 			submittedCount = myMdmSubmitSvc.submitSourceResourceTypeToMdm(resourceType, criteria);

hapi-fhir-server-mdm/src/main/java/ca/uhn/fhir/mdm/provider/MdmProviderLoader.java

@@ -26,6 +26,7 @@ import ca.uhn.fhir.mdm.api.IMdmControllerSvc;
 import ca.uhn.fhir.mdm.api.IMdmExpungeSvc;
 import ca.uhn.fhir.mdm.api.IMdmMatchFinderSvc;
 import ca.uhn.fhir.mdm.api.IMdmSubmitSvc;
+import ca.uhn.fhir.rest.server.IRestfulServerDefaults;
 import ca.uhn.fhir.rest.server.provider.ResourceProviderFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
@@ -46,6 +47,8 @@ public class MdmProviderLoader {
 	private IMdmExpungeSvc myMdmExpungeSvc;
 	@Autowired
 	private IMdmSubmitSvc myMdmSubmitSvc;
+	@Autowired
+	private IRestfulServerDefaults myRestfulServerDefaults;
 
 	private BaseMdmProvider myMdmProvider;
 
@@ -54,7 +57,7 @@ public class MdmProviderLoader {
 			case DSTU3:
 			case R4:
 				myResourceProviderFactory.addSupplier(() -> {
-					myMdmProvider = new MdmProviderDstu3Plus(myFhirContext, myMdmControllerSvc, myMdmMatchFinderSvc, myMdmExpungeSvc, myMdmSubmitSvc);
+					myMdmProvider = new MdmProviderDstu3Plus(myFhirContext, myMdmControllerSvc, myMdmMatchFinderSvc, myMdmExpungeSvc, myMdmSubmitSvc, myRestfulServerDefaults);
 					return myMdmProvider;
 				});
 				break;

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/RestfulServerUtils.java

@@ -249,6 +249,10 @@ public class RestfulServerUtils {
 
 
 	public static String createLinkSelf(String theServerBase, RequestDetails theRequest) {
+		return createLinkSelfWithoutGivenParameters(theServerBase, theRequest, null);
+	}
+
+	public static String createLinkSelfWithoutGivenParameters(String theServerBase, RequestDetails theRequest, List<String> excludedParameterNames) {
 		StringBuilder b = new StringBuilder();
 		b.append(theServerBase);
 
@@ -265,21 +269,24 @@ public class RestfulServerUtils {
 			boolean first = true;
 			Map<String, String[]> parameters = theRequest.getParameters();
 			for (String nextParamName : new TreeSet<>(parameters.keySet())) {
-				for (String nextParamValue : parameters.get(nextParamName)) {
+				if (excludedParameterNames != null && !excludedParameterNames.contains(nextParamName)) {
-					if (first) {
+					for (String nextParamValue : parameters.get(nextParamName)) {
-						b.append('?');
+						if (first) {
-						first = false;
+							b.append('?');
-					} else {
+							first = false;
-						b.append('&');
+						} else {
+							b.append('&');
+						}
+						b.append(UrlUtil.escapeUrlParam(nextParamName));
+						b.append('=');
+						b.append(UrlUtil.escapeUrlParam(nextParamValue));
 					}
-					b.append(UrlUtil.escapeUrlParam(nextParamName));
-					b.append('=');
-					b.append(UrlUtil.escapeUrlParam(nextParamValue));
 				}
 			}
 		}
 
 		return b.toString();
+
 	}
 
 	public static String createOffsetPagingLink(BundleLinks theBundleLinks, String requestPath, String tenantId, Integer theOffset, Integer theCount, Map<String, String[]> theRequestParameters) {