| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package beam |
| |
| import ( |
| "github.com/apache/beam/sdks/v2/go/pkg/beam/core/graph" |
| ) |
| |
| // Impulse emits a single empty []byte into the global window. The resulting |
| // PCollection is a singleton of type []byte. |
| // |
| // The purpose of Impulse is to trigger another transform, such as |
| // ones that take all information as side inputs. |
| func Impulse(s Scope) PCollection { |
| return ImpulseValue(s, []byte{}) |
| } |
| |
| // ImpulseValue emits the supplied byte slice into the global window. The resulting |
| // PCollection is a singleton of type []byte. |
| func ImpulseValue(s Scope, value []byte) PCollection { |
| if !s.IsValid() { |
| panic("Invalid scope") |
| } |
| edge := graph.NewImpulse(s.real, s.scope, value) |
| ret := PCollection{edge.Output[0].To} |
| ret.SetCoder(NewCoder(ret.Type())) |
| return ret |
| } |