/* * Copyright (C) 2012, 2016 higherfrequencytrading.com * Copyright (C) 2016 Roman Leventov * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package net.openhft.chronicle.hash; import net.openhft.chronicle.map.MapAbsentEntry; import net.openhft.chronicle.map.MapEntry; import net.openhft.chronicle.set.SetEntry; /** * Abstracts entries of hash containers, created by {@link ChronicleHashBuilder}s * with {@link ChronicleHashBuilder#checksumEntries(boolean)} configured to {@code true}. There is * no method that returns {@code ChecksumEntry}, {@link MapEntry} or {@link SetEntry} could be * <i>casted</i> to {@code ChecksumEntry} to access it's methods. * * <p>See <a href="https://github.com/OpenHFT/Chronicle-Map#entry-checksums">Entry checksums</a> * section in the Chronicle Map tutorial for usage examples of this interface. */ public interface ChecksumEntry { /** * Re-computes and stores checksum for the entry. This method <i>shouldn't</i> be called before * or after ordinary operations like {@link MapAbsentEntry#doInsert(Data)}, {@link * MapEntry#doReplaceValue(Data)}: it is performed automatically underneath. Call this method, * only when value bytes was updated directly, for example though flyweight implementation of * a <a href="https://github.com/OpenHFT/Chronicle-Values#value-interface-specification">value * interface</a>. * * @throws UnsupportedOperationException if checksums are not stored in the containing Chronicle * Hash * @throws RuntimeException if the context of this entry is locked improperly, e. g. on the * {@linkplain HashQueryContext#readLock() read} level, that is not upgradable to the * {@linkplain HashQueryContext#updateLock() update} level. Calling {@code updateChecksum()} * method is enabled when at least update lock is held. */ void updateChecksum(); /** * Computes checksum from the entry bytes and checks whether it is equal to the stored checksum. * * @return {@code true} if stored checksum equals to checksum computed from the entry bytes * @throws UnsupportedOperationException if checksums are not stored in the containing Chronicle * Hash * @throws RuntimeException if the context of this entry is locked improperly, e. g. on the * {@linkplain HashQueryContext#readLock() read} level, that is not upgradable to the * {@linkplain HashQueryContext#updateLock() update} level. Calling {@code checkSum()} method is * enabled when at least update lock is held. */ boolean checkSum(); }