From d0eb855391558f3f7817e61efd5342c7d2d72798 Mon Sep 17 00:00:00 2001
From: Michael Buckley <michaelabuckley@gmail.com>
Date: Wed, 6 Nov 2024 13:20:37 -0500
Subject: [PATCH] Change Repository search interface from Map to Multimap
 (#6445)

Change Map to Multimap to support multiple and clauses.
---
 .../ca/uhn/fhir/repository/Repository.java    | 44 ++++++++++++++++++-
 .../7_6_0/6445-repository-api-multimap.yaml   |  4 ++
 2 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/7_6_0/6445-repository-api-multimap.yaml

diff --git a/hapi-fhir-base/src/main/java/ca/uhn/fhir/repository/Repository.java b/hapi-fhir-base/src/main/java/ca/uhn/fhir/repository/Repository.java
index e859a9ae569..c272656f47a 100644
--- a/hapi-fhir-base/src/main/java/ca/uhn/fhir/repository/Repository.java
+++ b/hapi-fhir-base/src/main/java/ca/uhn/fhir/repository/Repository.java
@@ -28,6 +28,8 @@ import ca.uhn.fhir.rest.server.exceptions.ForbiddenOperationException;
 import ca.uhn.fhir.rest.server.exceptions.InternalErrorException;
 import ca.uhn.fhir.rest.server.exceptions.NotImplementedOperationException;
 import com.google.common.annotations.Beta;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Multimap;
 import org.hl7.fhir.instance.model.api.IBaseBundle;
 import org.hl7.fhir.instance.model.api.IBaseConformance;
 import org.hl7.fhir.instance.model.api.IBaseParameters;
@@ -231,6 +233,23 @@ public interface Repository {
 
 	// Querying starts here
 
+	/**
+	 * Searches this repository
+	 *
+	 * @see <a href="https://www.hl7.org/fhir/http.html#search">FHIR search</a>
+	 *
+	 * @param <B> a Bundle type
+	 * @param <T> a Resource type
+	 * @param bundleType the class of the Bundle type to return
+	 * @param resourceType the class of the Resource type to search
+	 * @param searchParameters the searchParameters for this search
+	 * @return a Bundle with the results of the search
+	 */
+	default <B extends IBaseBundle, T extends IBaseResource> B search(
+			Class<B> bundleType, Class<T> resourceType, Multimap<String, List<IQueryParameterType>> searchParameters) {
+		return this.search(bundleType, resourceType, searchParameters, Collections.emptyMap());
+	}
+
 	/**
 	 * Searches this repository
 	 *
@@ -264,9 +283,32 @@ public interface Repository {
 	<B extends IBaseBundle, T extends IBaseResource> B search(
 			Class<B> bundleType,
 			Class<T> resourceType,
-			Map<String, List<IQueryParameterType>> searchParameters,
+			Multimap<String, List<IQueryParameterType>> searchParameters,
 			Map<String, String> headers);
 
+	/**
+	 * Searches this repository
+	 *
+	 * @see <a href="https://www.hl7.org/fhir/http.html#search">FHIR search</a>
+	 *
+	 * @param <B> a Bundle type
+	 * @param <T> a Resource type
+	 * @param bundleType the class of the Bundle type to return
+	 * @param resourceType the class of the Resource type to search
+	 * @param searchParameters the searchParameters for this search
+	 * @param headers headers for this request, typically key-value pairs of HTTP headers
+	 * @return a Bundle with the results of the search
+	 */
+	default <B extends IBaseBundle, T extends IBaseResource> B search(
+			Class<B> bundleType,
+			Class<T> resourceType,
+			Map<String, List<IQueryParameterType>> searchParameters,
+			Map<String, String> headers) {
+		ArrayListMultimap<String, List<IQueryParameterType>> multimap = ArrayListMultimap.create();
+		searchParameters.forEach(multimap::put);
+		return this.search(bundleType, resourceType, multimap, headers);
+	}
+
 	// Paging starts here
 
 	/**
diff --git a/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/7_6_0/6445-repository-api-multimap.yaml b/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/7_6_0/6445-repository-api-multimap.yaml
new file mode 100644
index 00000000000..841287f278d
--- /dev/null
+++ b/hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/7_6_0/6445-repository-api-multimap.yaml
@@ -0,0 +1,4 @@
+---
+type: add
+issue: 6445
+title: "Add Multimap versions of the search() methods to Repository to support queries like `Patient?_tag=a&_tag=b`"