learning/katas/go/core_transforms/composite/composite/pkg/task/task.go

// 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 task

import (
	"github.com/apache/beam/sdks/go/pkg/beam"
	"github.com/apache/beam/sdks/go/pkg/beam/transforms/stats"
)

func ApplyTransform(s beam.Scope, input beam.PCollection) beam.PCollection {
	s = s.Scope("CountCharacters")
	characters := extractNonSpaceCharacters(s, input)
	return stats.Count(s, characters)
}

func extractNonSpaceCharacters(s beam.Scope, input beam.PCollection) beam.PCollection {
	return beam.ParDo(s, func(line string, emit func(string)){
		for _, k := range line {
			char := string(k)
			if char != " " {
				emit(char)
			}
		}
	}, input)
}