Add additional way to get scheduled jobs by ids

Change parameter type, introduce exception for 0 length

Simplify get by id function

Remove gap

src/Hangfire.Core/Storage/IMonitoringApi.cs

@@ -31,6 +31,7 @@ public interface IMonitoringApi
 
         JobList<ProcessingJobDto> ProcessingJobs(int from, int count);
         JobList<ScheduledJobDto> ScheduledJobs(int from, int count);
+        JobList<ScheduledJobDto> ScheduledJobsByIds(long[] jobIds);
         JobList<SucceededJobDto> SucceededJobs(int from, int count);
         JobList<FailedJobDto> FailedJobs(int from, int count);
         JobList<DeletedJobDto> DeletedJobs(int from, int count);

src/Hangfire.Core/Storage/JobStorageMonitor.cs

@@ -30,6 +30,7 @@ public abstract class JobStorageMonitor : IMonitoringApi
         public abstract JobList<FetchedJobDto> FetchedJobs(string queue, int from, int perPage);
         public abstract JobList<ProcessingJobDto> ProcessingJobs(int from, int count);
         public abstract JobList<ScheduledJobDto> ScheduledJobs(int from, int count);
+        public abstract JobList<ScheduledJobDto> ScheduledJobsByIds(long[] jobIds);
         public abstract JobList<SucceededJobDto> SucceededJobs(int from, int count);
         public abstract JobList<FailedJobDto> FailedJobs(int from, int count);
         public abstract JobList<DeletedJobDto> DeletedJobs(int from, int count);

src/Hangfire.SqlServer/SqlServerMonitoringApi.cs

@@ -114,6 +114,27 @@ public override JobList<ScheduledJobDto> ScheduledJobs(int @from, int count)
                 }));
         }
 
+        public override JobList<ScheduledJobDto> ScheduledJobsByIds(long[] jobIds)
+        {
+            if (jobIds.Length == 0)
+                throw new InvalidOperationException("Sequence contains no elements");
+
+            return UseConnection(connection => GetJobsByIdsList(
+                connection,
+                jobIds,
+                ScheduledState.StateName,
+                (sqlJob, job, invocationData, loadException, stateData) => new ScheduledJobDto
+            {
+                Job = job,
+                LoadException = loadException,
+                InvocationData = invocationData,
+                InScheduledState = ScheduledState.StateName.Equals(sqlJob.StateName, StringComparison.OrdinalIgnoreCase),
+                EnqueueAt = JobHelper.DeserializeNullableDateTime(stateData["EnqueueAt"]) ?? DateTime.MinValue,
+                ScheduledAt = sqlJob.StateChanged,
+                StateData = stateData
+            }));
+        }
+
         public override IDictionary<DateTime, long> SucceededByDatesCount()
         {
             return UseConnection(connection => 
@@ -626,6 +647,27 @@ private JobList<TDto> GetJobs<TDto>(
             return DeserializeJobs(jobs, selector);
         }
 
+        private JobList<TDto> GetJobsByIdsList<TDto>(
+            DbConnection connection,
+            long[] jobIds,
+            string stateName,
+            Func<SqlJob, Job, InvocationData, JobLoadException, SafeDictionary<string, string>, TDto> selector)
+        {
+            string jobsSql =
+$@";select j.*, s.Reason as StateReason, s.Data as StateData, s.CreatedAt as StateChanged
+from [{_storage.SchemaName}].Job j with (nolock, forceseek)
+left join [{_storage.SchemaName}].State s with (nolock, forceseek) on j.StateId = s.Id and j.Id = s.JobId
+where j.Id in @ids";
+
+            var jobs = connection.Query<SqlJob>(
+                    jobsSql,
+                    new { stateName = stateName , ids = jobIds },
+                    commandTimeout: _storage.CommandTimeout)
+                .ToList();
+
+            return DeserializeJobs(jobs, selector);
+        }
+
         private static JobList<TDto> DeserializeJobs<TDto>(
             ICollection<SqlJob> jobs,
             Func<SqlJob, Job, InvocationData, JobLoadException, SafeDictionary<string, string>, TDto> selector)