YARN-5870. Expose getApplications API in YarnClient with GetApplicationsRequest parameter. Contributed by Jian He.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/main/java/org/apache/hadoop/yarn/client/api/YarnClient.java

@@ -32,6 +32,8 @@ import org.apache.hadoop.classification.InterfaceStability.Unstable;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.service.AbstractService;
 import org.apache.hadoop.yarn.api.ApplicationClientProtocol;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationsRequest;
+import org.apache.hadoop.yarn.api.protocolrecords.GetNewApplicationRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.GetNewReservationResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.ReservationDeleteRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.ReservationDeleteResponse;
@@ -377,6 +379,30 @@ public abstract class YarnClient extends AbstractService {
       EnumSet<YarnApplicationState> applicationStates) throws YarnException,
       IOException;
 
+  /**
+   * <p>
+   * Get a list of ApplicationReports that match the given
+   * {@link GetApplicationsRequest}.
+   *</p>
+   *
+   * <p>
+   * If the user does not have <code>VIEW_APP</code> access for an application
+   * then the corresponding report will be filtered as described in
+   * {@link #getApplicationReport(ApplicationId)}.
+   * </p>
+   *
+   * @param request the request object to get the list of applications.
+   * @return The list of ApplicationReports that match the request
+   * @throws YarnException Exception specific to YARN.
+   * @throws IOException Exception mostly related to connection errors.
+   */
+  public List<ApplicationReport> getApplications(GetApplicationsRequest request)
+      throws YarnException, IOException {
+    throw new UnsupportedOperationException(
+        "The sub-class extending " + YarnClient.class.getName()
+            + " is expected to implement this !");
+  }
+
   /**
    * <p>
    * Get metrics ({@link YarnClusterMetrics}) about the cluster.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/main/java/org/apache/hadoop/yarn/client/api/impl/YarnClientImpl.java

@@ -543,6 +543,13 @@ public class YarnClientImpl extends YarnClient {
     return response.getApplicationList();
   }
 
+  @Override
+  public List<ApplicationReport> getApplications(
+      GetApplicationsRequest request) throws YarnException, IOException {
+    GetApplicationsResponse response = rmClient.getApplications(request);
+    return response.getApplicationList();
+  }
+
   @Override
   public YarnClusterMetrics getYarnClusterMetrics() throws YarnException,
       IOException {