80 lines
2.6 KiB
Java
80 lines
2.6 KiB
Java
/*
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* This file is part of BlueMap, licensed under the MIT License (MIT).
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*
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* Copyright (c) Blue (Lukas Rieger) <https://bluecolored.de>
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* Copyright (c) contributors
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package de.bluecolored.bluemap.core.storage.sql;
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import java.util.Spliterator;
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import java.util.Spliterators;
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import java.util.function.Consumer;
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import java.util.function.IntFunction;
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public class PageSpliterator<T> implements Spliterator<T> {
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private final IntFunction<T[]> pageSupplier;
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private T[] lastBatch;
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private int pos;
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private int page;
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public PageSpliterator(IntFunction<T[]> pageSupplier) {
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this.pageSupplier = pageSupplier;
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}
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@Override
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public synchronized boolean tryAdvance(Consumer<? super T> action) {
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if (!refill()) return false;
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action.accept(lastBatch[pos++]);
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return true;
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}
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@Override
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public synchronized Spliterator<T> trySplit() {
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if (!refill()) return null;
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int from = pos;
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pos = lastBatch.length;
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return Spliterators.spliterator(
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lastBatch, from, pos,
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characteristics()
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);
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}
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@Override
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public long estimateSize() {
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return Long.MAX_VALUE;
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}
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@Override
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public int characteristics() {
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return 0;
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}
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@SuppressWarnings("BooleanMethodIsAlwaysInverted")
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private synchronized boolean refill() {
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if (lastBatch != null && pos < lastBatch.length) return true;
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pos = 0;
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lastBatch = pageSupplier.apply(page++);
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return lastBatch != null && lastBatch.length > 0;
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}
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}
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