Added support for merge request approvals.

src/main/java/org/gitlab4j/api/MergeRequestApi.java

@@ -265,7 +265,7 @@ public class MergeRequestApi extends AbstractApi {
      * @return the updated merge request
      * @throws GitLabApiException if any exception occurs
      */
-    public MergeRequest acceptMergeRequest(Integer projectId, Integer mergeRequestId) throws GitLabApiException {
+    public MergeRequest cancelMergeRequest(Integer projectId, Integer mergeRequestId) throws GitLabApiException {
 
         if (projectId == null) {
             throw new RuntimeException("projectId cannot be null");
@@ -278,4 +278,84 @@ public class MergeRequestApi extends AbstractApi {
         Response response = put(Response.Status.OK, null, "projects", projectId, "merge_requests", mergeRequestId, "cancel_merge_when_pipeline_succeeds");
         return (response.readEntity(MergeRequest.class));
     }
+
+    /**
+     * Get the merge request with approval information.
+     *
+     * Note: This API endpoint is only available on 8.9 EE and above.
+     *
+     * GET /projects/:id/merge_requests/:merge_request_iid/approvals
+     *
+     * @param projectId the project ID of the merge request
+     * @param mergeRequestId the internal ID of the merge request
+     * @return a MergeRequest instance with approval information included
+     * @throws GitLabApiException if any exception occurs
+     */
+    public MergeRequest getMergeRequestApprovals(Integer projectId, Integer mergeRequestId) throws GitLabApiException {
+
+        if (projectId == null) {
+            throw new RuntimeException("projectId cannot be null");
+        }
+
+        if (mergeRequestId == null) {
+            throw new RuntimeException("mergeRequestId cannot be null");
+        }
+
+        Response response = get(Response.Status.OK, null, "projects", projectId, "merge_requests", mergeRequestId, "approvals");
+        return (response.readEntity(MergeRequest.class));
+    }
+
+    /**
+     * Approve a merge request.
+     *
+     * Note: This API endpoint is only available on 8.9 EE and above.
+     *
+     * POST /projects/:id/merge_requests/:merge_request_iid/approve
+     *
+     * @param projectId the project ID of the merge request
+     * @param mergeRequestId the internal ID of the merge request
+     * @param sha the HEAD of the merge request, optional
+     * @return a MergeRequest instance with approval information included
+     * @throws GitLabApiException if any exception occurs
+     */
+    public MergeRequest approveMergeRequest(Integer projectId, Integer mergeRequestId, String sha) throws GitLabApiException {
+
+        if (projectId == null) {
+            throw new RuntimeException("projectId cannot be null");
+        }
+
+        if (mergeRequestId == null) {
+            throw new RuntimeException("mergeRequestId cannot be null");
+        }
+
+        Form formData = new GitLabApiForm().withParam("sha", sha);
+        Response response = post(Response.Status.OK, formData, "projects", projectId, "merge_requests", mergeRequestId, "approve");
+        return (response.readEntity(MergeRequest.class));
+    }
+
+    /**
+     * Unapprove a merge request.
+     *
+     * Note: This API endpoint is only available on 8.9 EE and above.
+     *
+     * POST /projects/:id/merge_requests/:merge_request_iid/unapprove
+     *
+     * @param projectId the project ID of the merge request
+     * @param mergeRequestId the internal ID of the merge request
+     * @return a MergeRequest instance with approval information included
+     * @throws GitLabApiException if any exception occurs
+     */
+    public MergeRequest unapproveMergeRequest(Integer projectId, Integer mergeRequestId) throws GitLabApiException {
+
+        if (projectId == null) {
+            throw new RuntimeException("projectId cannot be null");
+        }
+
+        if (mergeRequestId == null) {
+            throw new RuntimeException("mergeRequestId cannot be null");
+        }
+
+        Response response = post(Response.Status.OK, (Form)null, "projects", projectId, "merge_requests", mergeRequestId, "unapprove");
+        return (response.readEntity(MergeRequest.class));
+    }
 }

src/main/java/org/gitlab4j/api/models/MergeRequest.java

@@ -7,6 +7,11 @@ import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlRootElement;
 
+import org.gitlab4j.api.utils.JacksonJson;
+
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+
 @XmlRootElement
 @XmlAccessorType(XmlAccessType.FIELD)
 public class MergeRequest {
@@ -43,6 +48,14 @@ public class MergeRequest {
     private String webUrl;
     private Boolean workInProgress;
 
+    // The approval fields will only be available when listing approvals, approving  or unapproving a merge reuest.
+    private Integer approvalsRequired;
+    private Integer approvalsMissing;
+
+    @JsonSerialize(using = JacksonJson.UserListSerializer.class)
+    @JsonDeserialize(using = JacksonJson.UserListDeserializer.class)
+    private List<User> approvedBy;
+
     public Integer getApprovalsBeforeMerge() {
         return approvalsBeforeMerge;
     }
@@ -291,6 +304,72 @@ public class MergeRequest {
         this.workInProgress = workInProgress;
     }
 
+    /**
+     * Get the number of approvals required for the merge request.
+     *
+     * NOTE: This property will only be used when listing, approiving, or unapproving a merge request.
+     *
+     * @return the number of approvals required for the merge request
+     */
+    public Integer getApprovalsRequired() {
+        return approvalsRequired;
+    }
+
+    /**
+     * Set the number of approvals required for the merge request.
+     *
+     * NOTE: This property will only be used when listing, approiving, or unapproving a merge request.
+     *
+     * @param approvalsRequired the number of approvals required for the merge request
+     */
+    public void setApprovalsRequired(Integer approvalsRequired) {
+        this.approvalsRequired = approvalsRequired;
+    }
+
+    /**
+     * Get the number of approvals missing for the merge request.
+     *
+     * NOTE: This property will only be used when listing, approiving, or unapproving a merge request.
+     *
+     * @return the number of approvals missing for the merge request
+     */
+    public Integer getApprovalsMissing() {
+        return approvalsMissing;
+    }
+
+    /**
+     * Set the number of approvals missing for the merge request.
+     *
+     * NOTE: This property will only be used when listing, approiving, or unapproving a merge request.
+     *
+     * @param approvalsMissing the number of approvals missing for the merge request
+     */
+    public void setApprovalsMissing(Integer approvalsMissing) {
+        this.approvalsMissing = approvalsMissing;
+    }
+
+    /**
+     * Get the list of users that have approved the merge request.
+     *
+     * NOTE: This property will only be used when listing, approiving, or unapproving a merge request.
+     *
+     * @return the list of users that have approved the merge request
+     */
+    public List<User> getApprovedBy() {
+        return approvedBy;
+    }
+
+    /**
+     * Set the list of users that have approved the merge request.
+     *
+     * NOTE: This property will only be used when listing, approiving, or unapproving a merge request.
+     *
+     * @param approvedBy the list of users that have approved the merge request
+     */
+    public void setApprovedBy(List<User> approvedBy) {
+        this.approvedBy = approvedBy;
+    }
+
     public static final boolean isValid(MergeRequest mergeRequest) {
         return (mergeRequest != null && mergeRequest.getId() != null);
     }

src/main/java/org/gitlab4j/api/utils/JacksonJson.java

@@ -5,7 +5,9 @@ import java.io.IOException;
 import java.io.Reader;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
+import java.util.ArrayList;
 import java.util.Date;
+import java.util.List;
 import java.util.TimeZone;
 
 import javax.ws.rs.Produces;
@@ -13,6 +15,8 @@ import javax.ws.rs.core.MediaType;
 import javax.ws.rs.ext.ContextResolver;
 import javax.ws.rs.ext.Provider;
 
+import org.gitlab4j.api.models.User;
+
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.core.JsonGenerationException;
 import com.fasterxml.jackson.core.JsonGenerator;
@@ -23,6 +27,7 @@ import com.fasterxml.jackson.databind.DeserializationContext;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JsonDeserializer;
 import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.JsonSerializer;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectWriter;
@@ -168,4 +173,49 @@ public class JacksonJson extends JacksonJaxbJsonProvider implements ContextResol
             }
         }
     }
-}
+
\ No newline at end of file
+    /**
+     * Serializer for the odd User instances in the "approved_by" array in the merge_request JSON.
+     */
+    public static class UserListSerializer extends JsonSerializer<List<User>> {
+
+        @Override
+        public void serialize(List<User> value, JsonGenerator jgen,
+                SerializerProvider provider) throws IOException,
+                JsonProcessingException {
+
+            jgen.writeStartArray();
+            for (User user : value) {
+                jgen.writeStartObject();
+                jgen.writeObjectField("user", user);
+                jgen.writeEndObject();
+            }
+            jgen.writeEndArray();
+        }
+    }
+
+    /**
+     * Deserializer for the odd User instances in the "approved_by" array in the merge_request JSON.
+     */
+    public static class UserListDeserializer extends JsonDeserializer<List<User>> {
+
+        private static final ObjectMapper mapper = new JacksonJson().getObjectMapper();
+
+        @Override
+        public List<User> deserialize(JsonParser jsonParser, DeserializationContext context)
+                throws IOException, JsonProcessingException {
+
+            JsonNode tree = jsonParser.readValueAsTree();
+            int numUsers = tree.size();
+            List<User> users = new ArrayList<>(numUsers);
+            for (int i = 0; i < numUsers; i++) {
+                JsonNode node = tree.get(i);
+                JsonNode userNode = node.get("user");
+                User user = mapper.treeToValue(userNode,  User.class);
+                users.add(user);
+            }
+
+            return (users);
+        }
+    }
+}

src/test/java/org/gitlab4j/api/TestGitLabApiBeans.java

@@ -202,18 +202,18 @@ public class TestGitLabApiBeans {
             e.printStackTrace();
         }
     }
-/*
+
     @Test
-    public void testMergeRequestComment() {
+    public void testMergeRequestApprovals() {
 
         try {
-            MergeRequestComment mergeRequestComment = makeFakeApiCall(MergeRequestComment.class, "merge-request-comment");
-            assertTrue(compareJson(mergeRequestComment, "merge-request-comment"));
+            MergeRequest mergeRequestApprovals = makeFakeApiCall(MergeRequest.class, "approvals");
+            assertTrue(compareJson(mergeRequestApprovals, "approvals"));
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
-*/
+
     @Test
     public void testMergeRequest() {