com.tencent.angel.sona.graph.utils.BatchIter.scala Maven / Gradle / Ivy

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/*
 * Tencent is pleased to support the open source community by making Angel available.
 *
 * Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed 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
 *
 * https://opensource.org/licenses/Apache-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 com.tencent.angel.sona.graph.utils
import scala.collection.mutable.ArrayBuffer
import scala.reflect.ClassTag

object BatchIter {
  def apply[T: ClassTag](iterator: Iterator[T], batchSize: Int): Iterator[Array[T]] = {
    new Iterator[Array[T]] {
      val buffer = new ArrayBuffer[T]()

      override def hasNext: Boolean = iterator.hasNext

      override def next(): Array[T] = {
        buffer.clear()
        var num = 0
        while (num < batchSize && iterator.hasNext) {
          num += 1
          buffer += iterator.next()
        }
        buffer.toArray
      }
    }
  }
}