ambari-metrics-anomaly-detection-service/src/main/scala/org/apache/ambari/metrics/adservice/metadata/InputMetricDefinitionParser.scala

/*
 * 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 org.apache.ambari.metrics.adservice.metadata

import java.io.File

import org.apache.ambari.metrics.adservice.app.ADServiceScalaModule

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper

object InputMetricDefinitionParser {

  def parseInputDefinitionsFromDirectory(directory: String): List[MetricSourceDefinition] = {

    if (directory == null) {
      return List.empty[MetricSourceDefinition]
    }
    val mapper = new ObjectMapper() with ScalaObjectMapper
    mapper.registerModule(new ADServiceScalaModule)
    val metricSourceDefinitions: scala.collection.mutable.MutableList[MetricSourceDefinition] =
      scala.collection.mutable.MutableList.empty[MetricSourceDefinition]

    for (file <- getFilesInDirectory(directory)) {
      val source = scala.io.Source.fromFile(file)
      val lines = try source.mkString finally source.close()
      val definition: MetricSourceDefinition = mapper.readValue[MetricSourceDefinition](lines)
      if (definition != null) {
        metricSourceDefinitions.+=(definition)
      }
    }
    metricSourceDefinitions.toList
  }

  private def getFilesInDirectory(directory: String): List[File] = {
    val dir = new File(directory)
    if (dir.exists && dir.isDirectory) {
      dir.listFiles.filter(_.isFile).toList
    } else {
      List[File]()
    }
  }
}