| /* |
| * 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.cassandra.spark.reader.common; |
| |
| /** |
| * A GC friendly long[]. |
| * Allocating large arrays (that are not short-lived) generate fragmentation |
| * in old-gen space. This breaks such large long array into fixed size pages |
| * to avoid that problem. |
| */ |
| public class BigLongArray |
| { |
| static final int DEFAULT_PAGE_SIZE = 4096; |
| |
| private final long[][] pages; |
| public final int size; |
| private final int pageSize; |
| |
| public BigLongArray(int size) |
| { |
| if (size < 0) |
| { |
| throw new IndexOutOfBoundsException(String.format("BigLongArray size cannot be less than 0: %d)", size)); |
| } |
| this.size = size; |
| this.pageSize = DEFAULT_PAGE_SIZE; |
| |
| int lastPageSize = size % pageSize; |
| int fullPageCount = size / pageSize; |
| int pageCount = fullPageCount + (lastPageSize == 0 ? 0 : 1); |
| pages = new long[pageCount][]; |
| |
| for (int page = 0; page < fullPageCount; ++page) |
| { |
| pages[page] = new long[pageSize]; |
| } |
| |
| if (lastPageSize != 0) |
| { |
| pages[pages.length - 1] = new long[lastPageSize]; |
| } |
| } |
| |
| public void set(int index, long value) |
| { |
| checkIdx(index); |
| int page = index / pageSize; |
| int pageIdx = index % pageSize; |
| pages[page][pageIdx] = value; |
| } |
| |
| public long get(int index) |
| { |
| checkIdx(index); |
| int page = index / pageSize; |
| int pageIdx = index % pageSize; |
| return pages[page][pageIdx]; |
| } |
| |
| private void checkIdx(int index) |
| { |
| if (index < 0 || size < index) |
| { |
| throw new IndexOutOfBoundsException(String.format("%d is not within [0, %d)", index, size)); |
| } |
| } |
| } |