Add fieldSelector and option to RetrievePolicy

Signed-off-by: David Schwilk <david.schwilk@bosch.io>

java/src/main/java/org/eclipse/ditto/client/internal/OutgoingMessageFactory.java

@@ -222,7 +222,7 @@ public RetrieveThing retrieveThing(final ThingId thingId,
             final Option<?>... options) {
 
         return RetrieveThing.getBuilder(thingId,
-                        buildDittoHeaders(EnumSet.of(CONDITION, LIVE_CHANNEL_CONDITION), options))
+                buildDittoHeaders(EnumSet.of(CONDITION, LIVE_CHANNEL_CONDITION), options))
                 .withSelectedFields(JsonFactory.newFieldSelector(fields))
                 .build();
     }
@@ -298,16 +298,17 @@ public ModifyPolicy updatePolicy(final Policy policy, final Option<?>... options
         return ModifyPolicy.of(policyId, policy, headers);
     }
 
-    /**
-     * Builds a command to retrieve the policy with ID {@code policyId}.
-     *
-     * @param policyId the policy to retrieve.
-     * @return the {@link RetrievePolicy} command.
-     * @throws NullPointerException if the policyId is {@code null}.
-     * @since 1.1.0
-     */
-    public RetrievePolicy retrievePolicy(final PolicyId policyId) {
-        return RetrievePolicy.of(policyId, buildDittoHeaders(Collections.emptySet()));
+    public RetrievePolicy retrievePolicy(final PolicyId policyId, final Option<?>... options) {
+        return RetrievePolicy.of(policyId, buildDittoHeaders(Collections.emptySet(), options));
+    }
+
+    public RetrievePolicy retrievePolicy(final PolicyId policyId,
+            final Iterable<JsonPointer> fields,
+            final Option<?>... options) {
+
+        return RetrievePolicy.of(policyId,
+                buildDittoHeaders(Collections.emptySet(), options),
+                JsonFactory.newFieldSelector(fields));
     }
 
     /**

java/src/main/java/org/eclipse/ditto/client/policies/Policies.java

@@ -16,9 +16,11 @@
 import java.util.concurrent.CompletionStage;
 
 import org.eclipse.ditto.client.options.Option;
+import org.eclipse.ditto.json.JsonFieldSelector;
 import org.eclipse.ditto.json.JsonObject;
 import org.eclipse.ditto.policies.model.Policy;
 import org.eclipse.ditto.policies.model.PolicyId;
+import org.eclipse.ditto.things.model.Thing;
 
 /**
  * A {@code Policy} provides the basic functionality, which can be used to manage (i.e. create and delete)
@@ -153,12 +155,54 @@ public interface Policies {
     CompletionStage<Void> delete(PolicyId policyId, Option<?>... options);
 
     /**
-     * Gets the {@link org.eclipse.ditto.policies.model.Policy} specified by the given identifier.
+     * Gets the {@code Policy} specified by the given identifier.
      *
      * @param policyId the identifier of the Policy to be retrieved.
      * @return CompletionStage providing the requested Policy or a specific
      * {@link org.eclipse.ditto.base.model.exceptions.DittoRuntimeException} if the operation failed
      * @throws IllegalArgumentException if {@code policyId} is {@code null}.
      */
     CompletionStage<Policy> retrieve(PolicyId policyId);
+
+
+    /**
+     * Gets the {@code Policy} specified by the given identifier with the given options.
+     *
+     * @param options options that determine the behaviour of this method, see
+     * {@link org.eclipse.ditto.client.options.Options}.
+     * @return CompletionStage providing the requested {@link Thing} or a specific
+     * {@link org.eclipse.ditto.base.model.exceptions.DittoRuntimeException} if the operation failed.
+     * @throws NullPointerException if {@code options} is {@code null}.
+     * @throws IllegalArgumentException if {@code options} contains an option that is not allowed for retrieving
+     * a thing.
+     * @since 2.4.0
+     */
+    CompletionStage<Policy> retrieve(PolicyId policyId, Option<?>... options);
+
+    /**
+     * Retrieve the {@code Policy} specified by the given identifier, containing the fields specified by
+     * the given {@code fieldSelector}.
+     *
+     * @param fieldSelector a field selector object allowing to select a subset of fields on the Policy to be retrieved.
+     * @return CompletionStage providing the requested {@link Policy} or a specific
+     * {@link org.eclipse.ditto.base.model.exceptions.DittoRuntimeException} if the operation failed
+     * @since 2.4.0
+     */
+    CompletionStage<Policy> retrieve(PolicyId policyId, JsonFieldSelector fieldSelector);
+
+    /**
+     * Gets the {@code Policy} specified by the given identifier with the given options, containing the fields
+     * specified by the given {@code fieldSelector}.
+     *
+     * @param fieldSelector a field selector object allowing to select a subset of fields on the Policy to be retrieved.
+     * @param options options that determine the behaviour of this method, see
+     * {@link org.eclipse.ditto.client.options.Options}.
+     * @return CompletionStage providing the requested {@link Policy} or a specific
+     * {@link org.eclipse.ditto.base.model.exceptions.DittoRuntimeException} if the operation failed.
+     * @throws NullPointerException if any argument is {@code null}.
+     * @throws IllegalArgumentException if {@code options} contains an option that is not allowed for retrieving
+     * a policy.
+     * @since 2.4.0
+     */
+    CompletionStage<Policy> retrieve(PolicyId policyId, JsonFieldSelector fieldSelector, Option<?>... options);
 }

java/src/main/java/org/eclipse/ditto/client/policies/internal/PoliciesImpl.java

@@ -30,6 +30,7 @@
 import org.eclipse.ditto.client.messaging.MessagingProvider;
 import org.eclipse.ditto.client.options.Option;
 import org.eclipse.ditto.client.policies.Policies;
+import org.eclipse.ditto.json.JsonFieldSelector;
 import org.eclipse.ditto.json.JsonObject;
 import org.eclipse.ditto.json.JsonValue;
 import org.eclipse.ditto.policies.model.PoliciesModelFactory;
@@ -176,14 +177,34 @@ public CompletionStage<Void> delete(final PolicyId policyId, final Option<?>...
     }
 
     @Override
-    public CompletionStage<Policy> retrieve(PolicyId policyId) {
+    public CompletionStage<Policy> retrieve(final PolicyId policyId) {
         final RetrievePolicy command = outgoingMessageFactory.retrievePolicy(policyId);
         return askPolicyCommand(command, RetrievePolicyResponse.class, response -> {
             final Policy policyFromResponse = response.getPolicy();
             return appendRevisionFromHeadersIfNeeded(policyFromResponse, response.getDittoHeaders());
         });
     }
 
+    @Override
+    public CompletionStage<Policy> retrieve(final PolicyId policyId, final Option<?>... options) {
+        final RetrievePolicy command = outgoingMessageFactory.retrievePolicy(policyId, options);
+        return askPolicyCommand(command, RetrievePolicyResponse.class, RetrievePolicyResponse::getPolicy);
+    }
+
+    @Override
+    public CompletionStage<Policy> retrieve(final PolicyId policyId, final JsonFieldSelector fieldSelector) {
+        final RetrievePolicy command = outgoingMessageFactory.retrievePolicy(policyId, fieldSelector);
+        return askPolicyCommand(command, RetrievePolicyResponse.class, RetrievePolicyResponse::getPolicy);
+    }
+
+    @Override
+    public CompletionStage<Policy> retrieve(final PolicyId policyId, final JsonFieldSelector fieldSelector,
+            final Option<?>... options) {
+
+        final RetrievePolicy command = outgoingMessageFactory.retrievePolicy(policyId, fieldSelector, options);
+        return askPolicyCommand(command, RetrievePolicyResponse.class, RetrievePolicyResponse::getPolicy);
+    }
+
     private static void assertThatPolicyHasId(final Policy policy) {
         if (!policy.getEntityId().isPresent()) {
             final String msgPattern = "Mandatory field <{0}> is missing!";

java/src/test/java/org/eclipse/ditto/client/DittoClientPoliciesTest.java

@@ -16,6 +16,8 @@
 import static org.eclipse.ditto.client.TestConstants.Policy.POLICY;
 import static org.eclipse.ditto.client.TestConstants.Policy.POLICY_ID;
 import static org.eclipse.ditto.client.TestConstants.Policy.POLICY_JSON_OBJECT;
+import static org.eclipse.ditto.client.TestConstants.Policy.POLICY_REVISION_ONLY_JSON_OBJECT;
+import static org.eclipse.ditto.client.TestConstants.Policy.REVISION_ONLY_POLICY;
 import static org.eclipse.ditto.client.assertions.ClientAssertions.assertThat;
 
 import java.util.Arrays;
@@ -27,10 +29,11 @@
 import java.util.function.Function;
 
 import org.assertj.core.api.Assertions;
+import org.eclipse.ditto.base.model.headers.DittoHeaders;
 import org.eclipse.ditto.client.internal.AbstractDittoClientTest;
 import org.eclipse.ditto.client.options.Options;
 import org.eclipse.ditto.json.JsonFactory;
-import org.eclipse.ditto.json.JsonMissingFieldException;
+import org.eclipse.ditto.json.JsonFieldSelector;
 import org.eclipse.ditto.policies.model.Policy;
 import org.eclipse.ditto.policies.model.signals.commands.PolicyCommand;
 import org.eclipse.ditto.policies.model.signals.commands.PolicyCommandResponse;
@@ -181,6 +184,54 @@ public void testRetrievePolicy() throws Exception {
         Assertions.assertThat(retrievePolicyResponse).isCompletedWithValue(POLICY);
     }
 
+    @Test
+    public void testRetrievePolicyWithOptions() {
+        final String correlationId = "abc";
+        client.policies()
+                .retrieve(POLICY_ID, Options.headers(DittoHeaders.newBuilder().correlationId(correlationId).build()))
+                .toCompletableFuture();
+        final RetrievePolicy command = expectMsgClass(RetrievePolicy.class);
+        Assertions.assertThat(command.getDittoHeaders().getCorrelationId()).contains(correlationId);
+    }
+
+    @Test
+    public void testRetrievePolicyWithInvalidOptions() {
+        Assertions.assertThatIllegalArgumentException().isThrownBy(() -> client.policies()
+                .retrieve(POLICY_ID, Options.condition("exists(entry)")));
+    }
+
+    @Test
+    public void testRetrievePolicyWithFieldSelector() throws Exception {
+        final CompletableFuture<Policy> retrievePolicyResponse = client.policies()
+                .retrieve(POLICY_ID, JsonFieldSelector.newInstance("_revision"))
+                .toCompletableFuture();
+        reply(RetrievePolicyResponse.of(POLICY_ID, POLICY_REVISION_ONLY_JSON_OBJECT,
+                expectMsgClass(RetrievePolicy.class).getDittoHeaders()));
+        retrievePolicyResponse.get(TIMEOUT, TIME_UNIT);
+        Assertions.assertThat(retrievePolicyResponse).isCompletedWithValue(REVISION_ONLY_POLICY);
+    }
+
+    @Test
+    public void testRetrievePolicyWithFieldSelectorAndOptions() throws Exception {
+        final String correlationId = "abc";
+        final CompletableFuture<Policy> retrievePolicyResponse = client.policies()
+                .retrieve(POLICY_ID, JsonFieldSelector.newInstance("_revision"),
+                        Options.headers(DittoHeaders.newBuilder().correlationId(correlationId).build()))
+                .toCompletableFuture();
+        final RetrievePolicy command = expectMsgClass(RetrievePolicy.class);
+        Assertions.assertThat(command.getDittoHeaders().getCorrelationId()).contains(correlationId);
+        reply(RetrievePolicyResponse.of(POLICY_ID, POLICY_REVISION_ONLY_JSON_OBJECT,
+                command.getDittoHeaders()));
+        retrievePolicyResponse.get(TIMEOUT, TIME_UNIT);
+        Assertions.assertThat(retrievePolicyResponse).isCompletedWithValue(REVISION_ONLY_POLICY);
+    }
+
+    @Test
+    public void testRetrievePolicyWithFieldSelectorAndInvalidOptions() {
+        Assertions.assertThatIllegalArgumentException().isThrownBy(() -> client.policies()
+                .retrieve(POLICY_ID, JsonFieldSelector.newInstance("_revision"), Options.condition("exists(entry)")));
+    }
+
     @Test
     public void testRetrievePolicyFails() {
         assertEventualCompletion(client.policies().retrieve(POLICY_ID).handle((response, error) -> {

java/src/test/java/org/eclipse/ditto/client/DittoClientThingTest.java

@@ -581,6 +581,15 @@ public void retrieveThingWithConditionOption() {
         assertThat(retrieveThing.getDittoHeaders()).containsEntry(DittoHeaderDefinition.CONDITION.getKey(), CONDITION);
     }
 
+    @Test
+    public void retrieveThingWithExtraFieldsOption() {
+        assertEventualCompletion(getManagement().forId(THING_ID)
+                .retrieve(Options.Consumption.extraFields(JsonFieldSelector.newInstance("_revision"))));
+        final RetrieveThing retrieveThing = expectMsgClass(RetrieveThing.class);
+        reply(RetrieveThingResponse.of(THING_ID, TestConstants.Thing.THING_V2.toJson(), retrieveThing.getDittoHeaders()));
+        assertThat(retrieveThing.getSelectedFields()).contains(JsonFieldSelector.newInstance("_revision"));
+    }
+
     @Test
     public void retrieveThingWithFieldSelectorAndConditionOption() {
         final JsonFieldSelector jsonFieldSelector = JsonFieldSelector.newInstance("attributes/manufacturer");

java/src/test/java/org/eclipse/ditto/client/TestConstants.java

@@ -217,6 +217,12 @@ public static final class Policy {
         public static final org.eclipse.ditto.policies.model.Policy POLICY =
                 PoliciesModelFactory.newPolicy(POLICY_JSON_OBJECT);
 
+        public static final JsonObject POLICY_REVISION_ONLY_JSON_OBJECT = JsonObject.of("{\n" +
+                "    \"_revision\": " + 1 + "\n" + "}");
+
+        public static final org.eclipse.ditto.policies.model.Policy REVISION_ONLY_POLICY =
+                PoliciesModelFactory.newPolicy(POLICY_REVISION_ONLY_JSON_OBJECT);
+
     }
 
 }