feat: add Get method to the JobQueue interface

examples/queue/file_system.go

@@ -234,6 +234,32 @@ func findHead() (quartz.ScheduledJob, error) {
 	return job, nil
 }
 
+// Get returns the scheduled job with the specified key without removing it
+// from the queue.
+func (jq *jobQueue) Get(jobKey *quartz.JobKey) (quartz.ScheduledJob, error) {
+	jq.mtx.Lock()
+	defer jq.mtx.Unlock()
+	logger.Trace("Get")
+	fileInfo, err := os.ReadDir(dataFolder)
+	if err != nil {
+		return nil, err
+	}
+	for _, file := range fileInfo {
+		if !file.IsDir() {
+			data, err := os.ReadFile(fmt.Sprintf("%s/%s", dataFolder, file.Name()))
+			if err == nil {
+				job, err := unmarshal(data)
+				if err == nil {
+					if jobKey.Equals(job.JobDetail().JobKey()) {
+						return job, nil
+					}
+				}
+			}
+		}
+	}
+	return nil, errors.New("no jobs found")
+}
+
 // Remove removes and returns the scheduled job with the specified key.
 func (jq *jobQueue) Remove(jobKey *quartz.JobKey) (quartz.ScheduledJob, error) {
 	jq.mtx.Lock()

quartz/error.go

@@ -8,6 +8,7 @@ import (
 // Errors
 var (
 	ErrIllegalArgument = errors.New("illegal argument")
+	ErrIllegalState    = errors.New("illegal state")
 	ErrCronParse       = errors.New("parse cron expression")
 	ErrJobNotFound     = errors.New("job not found")
 )
@@ -18,6 +19,12 @@ func illegalArgumentError(message string) error {
 	return fmt.Errorf("%w: %s", ErrIllegalArgument, message)
 }
 
+// illegalStateError returns an illegal state error with a custom
+// error message, which unwraps to ErrIllegalState.
+func illegalStateError(message string) error {
+	return fmt.Errorf("%w: %s", ErrIllegalState, message)
+}
+
 // cronParseError returns a cron parse error with a custom error message,
 // which unwraps to ErrCronParse.
 func cronParseError(message string) error {

quartz/error_test.go

@@ -17,6 +17,15 @@ func TestIllegalArgumentError(t *testing.T) {
 	assert.Equal(t, err.Error(), fmt.Sprintf("%s: %s", ErrIllegalArgument, message))
 }
 
+func TestIllegalStateError(t *testing.T) {
+	message := "job already exists"
+	err := illegalStateError(message)
+	if !errors.Is(err, ErrIllegalState) {
+		t.Fatal("error must match ErrIllegalState")
+	}
+	assert.Equal(t, err.Error(), fmt.Sprintf("%s: %s", ErrIllegalState, message))
+}
+
 func TestCronParseError(t *testing.T) {
 	message := "invalid field"
 	err := cronParseError(message)

quartz/queue.go

@@ -52,6 +52,10 @@ type JobQueue interface {
 	// Head returns the first scheduled job without removing it from the queue.
 	Head() (ScheduledJob, error)
 
+	// Get returns the scheduled job with the specified key without removing it
+	// from the queue.
+	Get(jobKey *JobKey) (ScheduledJob, error)
+
 	// Remove removes and returns the scheduled job with the specified key.
 	Remove(jobKey *JobKey) (ScheduledJob, error)
 
@@ -136,8 +140,8 @@ func (jq *jobQueue) Push(job ScheduledJob) error {
 				heap.Remove(&jq.delegate, i)
 				break
 			}
-			return fmt.Errorf("job with the key %s already exists",
-				job.JobDetail().jobKey)
+			return illegalStateError(fmt.Sprintf("job with the key %s already exists",
+				job.JobDetail().jobKey))
 		}
 	}
 	heap.Push(&jq.delegate, job)
@@ -164,6 +168,19 @@ func (jq *jobQueue) Head() (ScheduledJob, error) {
 	return jq.delegate[0], nil
 }
 
+// Get returns the scheduled job with the specified key without removing it
+// from the queue.
+func (jq *jobQueue) Get(jobKey *JobKey) (ScheduledJob, error) {
+	jq.mtx.Lock()
+	defer jq.mtx.Unlock()
+	for _, scheduled := range jq.delegate {
+		if scheduled.JobDetail().jobKey.Equals(jobKey) {
+			return scheduled, nil
+		}
+	}
+	return nil, jobNotFoundError(jobKey.String())
+}
+
 // Remove removes and returns the scheduled job with the specified key.
 func (jq *jobQueue) Remove(jobKey *JobKey) (ScheduledJob, error) {
 	jq.mtx.Lock()
@@ -174,7 +191,7 @@ func (jq *jobQueue) Remove(jobKey *JobKey) (ScheduledJob, error) {
 			return heap.Remove(&jq.delegate, i).(ScheduledJob), nil
 		}
 	}
-	return nil, jobNotFoundError(fmt.Sprintf("for key %s", jobKey))
+	return nil, jobNotFoundError(jobKey.String())
 }
 
 // ScheduledJobs returns the slice of all scheduled jobs in the queue.