/* * 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.bytes.Byteable; import net.openhft.chronicle.bytes.Bytes; import net.openhft.chronicle.hash.serialization.*; import net.openhft.chronicle.map.ChronicleMap; import net.openhft.chronicle.map.ChronicleMapBuilder; import net.openhft.chronicle.set.ChronicleSet; import net.openhft.chronicle.set.ChronicleSetBuilder; import org.jetbrains.annotations.NotNull; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.util.HashMap; import java.util.HashSet; import java.util.concurrent.ConcurrentHashMap; /** * Base interface for {@link ChronicleMapBuilder} and {@link ChronicleSetBuilder}, i. e. defines * <i>Chronicle hash container</i> configurations. * * <p>{@code ChronicleHashBuilder} is mutable. Configuration methods mutate the builder and return * <i>the builder itself</i> back to support chaining pattern, rather than the builder copies with * the corresponding configuration changed. To make an independent configuration, {@linkplain * #clone} the builder. * * <p>{@code ChronicleHashBuilder} instances are not safe for concurrent use from multiple threads, * if at least one of the threads mutates the {@code ChronicleHashBuilder}'s state. * * <p><a name="low-level-config"></a>There are some "low-level" configurations in this builder, * that require deep understanding of the Chronicle implementation design to be properly used. * Know what you do. These configurations are applied as-is, without extra round-ups, adjustments, * etc. * * @param <K> the type of keys in hash containers, created by this builder * @param <H> the container type, created by this builder, i. e. {@link ChronicleMap} or {@link * ChronicleSet} * @param <B> the concrete builder type, i. e. {@link ChronicleMapBuilder} * or {@link ChronicleSetBuilder} */ public interface ChronicleHashBuilder<K, H extends ChronicleHash<K, ?, ?, ?>, B extends ChronicleHashBuilder<K, H, B>> extends Cloneable { /** * Clones this builder. Useful for configuration persisting, because {@code * ChronicleHashBuilder}s are mutable and changed on each configuration method call. Original * and cloned builders are independent. * * @return a new clone of this builder */ B clone(); /** * Specify the name which will be given to a ChronicleHash, created by this builder. It is * recommended to give some distinctive name to each created {@code ChronicleHash}, because this * name is used when logging errors and warnings inside Chronicle Map library itself, so having * the concrete {@code ChronicleHash} name in logs may help to debug. * * <p>{@code name()} is a JVM-level configuration, it is not stored in the persistence file (or * the other way to say this: they are not parts of <a * href="https://github.com/OpenHFT/Chronicle-Map/tree/master/spec">the Chronicle Map data store * specification</a>) and have to be configured explicitly for each created on-heap {@code * ChronicleHash} instance, even if it is a view of an existing Chronicle Map data store. On the * other hand, {@code name()} could be different for different views of the same Chronicle * Map data store. * * @param name the name for a ChronicleHash, created by this builder * @return this builder back * @see ChronicleHash#name() */ B name(String name); /** * Set minimum number of segments in hash containers, constructed by this builder. See * concurrencyLevel in {@link ConcurrentHashMap}. * * @param minSegments the minimum number of segments in containers, constructed by this builder * @return this builder back */ B minSegments(int minSegments); /** * Configures the average number of bytes, taken by serialized form of keys, put into hash * containers, created by this builder. However, in many cases {@link #averageKey(Object)} might * be easier to use and more reliable. If key size is always the same, call {@link * #constantKeySizeBySample(Object)} method instead of this one. * * <p>{@code ChronicleHashBuilder} implementation heuristically chooses * {@linkplain #actualChunkSize(int) the actual chunk size} based on this configuration, that, * however, might result to quite high internal fragmentation, i. e. losses because only * integral number of chunks could be allocated for the entry. If you want to avoid this, you * should manually configure the actual chunk size in addition to this average key size * configuration, which is anyway needed. * * <p>If key is a boxed primitive type, a value interface or {@link Byteable} subclass, i. e. if * key size is known statically, it is automatically accounted and shouldn't be specified by * user. * * <p>Calling this method clears any previous {@link #constantKeySizeBySample(Object)} and * {@link #averageKey(Object)} configurations. * * @param averageKeySize the average number of bytes, taken by serialized form of keys * @return this builder back * @throws IllegalStateException if key size is known statically and shouldn't be configured * by user * @throws IllegalArgumentException if the given {@code keySize} is non-positive * @see #averageKey(Object) * @see #constantKeySizeBySample(Object) * @see #actualChunkSize(int) */ B averageKeySize(double averageKeySize); /** * Configures the average number of bytes, taken by serialized form of keys, put into hash * containers, created by this builder, by serializing the given {@code averageKey} using * the configured {@link #keyMarshallers(SizedReader, SizedWriter) keys marshallers}. * In some cases, {@link #averageKeySize(double)} might be easier to use, than constructing the * "average key". If key size is always the same, call {@link #constantKeySizeBySample( * Object)} method instead of this one. * * <p>{@code ChronicleHashBuilder} implementation heuristically chooses * {@linkplain #actualChunkSize(int) the actual chunk size} based on this configuration, that, * however, might result to quite high internal fragmentation, i. e. losses because only * integral number of chunks could be allocated for the entry. If you want to avoid this, you * should manually configure the actual chunk size in addition to this average key size * configuration, which is anyway needed. * * <p>If key is a boxed primitive type or {@link Byteable} subclass, i. e. if key size is known * statically, it is automatically accounted and shouldn't be specified by user. * * <p>Calling this method clears any previous {@link #constantKeySizeBySample(Object)} and * {@link #averageKeySize(double)} configurations. * * @param averageKey the average (by footprint in serialized form) key, is going to be put * into the hash containers, created by this builder * @return this builder back * @throws NullPointerException if the given {@code averageKey} is {@code null} * @see #averageKeySize(double) * @see #constantKeySizeBySample(Object) * @see #actualChunkSize(int) */ B averageKey(K averageKey); /** * Configures the constant number of bytes, taken by serialized form of keys, put into hash * containers, created by this builder. This is done by providing the {@code sampleKey}, all * keys should take the same number of bytes in serialized form, as this sample object. * * <p>If keys are of boxed primitive type or {@link Byteable} subclass, i. e. if key size is * known statically, it is automatically accounted and this method shouldn't be called. * * <p>If key size varies, method {@link #averageKeySize(double)} should be called instead of * this one. * * <p>Calling this method clears any previous {@link #averageKey(Object)} and * {@link #averageKeySize(double)} configurations. * * @param sampleKey the sample key * @return this builder back * @see #averageKeySize(double) */ B constantKeySizeBySample(K sampleKey); /** * Configures the size in bytes of allocation unit of hash container instances, created by this * builder. * * <p>{@link ChronicleMap} and {@link ChronicleSet} store their data off-heap, so it is required * to serialize key (and values, in {@code ChronicleMap} case) (unless they are direct {@link * Byteable} instances). Serialized key bytes (+ serialized value bytes, in {@code ChronicleMap} * case) + some metadata bytes comprise "entry space", which {@code ChronicleMap} or {@code * ChronicleSet} should allocate. So <i>chunk size</i> is the minimum allocation portion in the * hash containers, created by this builder. E. g. if chunk size is 100, the created container * could only allocate 100, 200, 300... bytes for an entry. If say 150 bytes of entry space are * required by the entry, 200 bytes will be allocated, 150 used and 50 wasted. This is called * internal fragmentation. * * <p>To minimize memory overuse and improve speed, you should pay decent attention to this * configuration. Alternatively, you can just trust the heuristics and doesn't configure * the chunk size. * * <p>Specify chunk size so that most entries would take from 5 to several dozens of chunks. * However, remember that operations with entries that span several chunks are a bit slower, * than with entries which take a single chunk. Particularly avoid entries to take more than * 64 chunks. * * <p>Example: if values in your {@code ChronicleMap} are adjacency lists of some social graph, * where nodes are represented as {@code long} ids, and adjacency lists are serialized in * efficient manner, for example as {@code long[]} arrays. Typical number of connections is * 100-300, maximum is 3000. In this case chunk size of * 30 * (8 bytes for each id) = 240 bytes would be a good choice: <pre>{@code * Map<Long, long[]> socialGraph = ChronicleMapBuilder * .of(Long.class, long[].class) * .entries(1_000_000_000L) * .averageValueSize(150 * 8) // 150 is average adjacency list size * .actualChunkSize(30 * 8) // average 5-6 chunks per entry * .create();}</pre> * * <p>This is a <a href="#low-level-config">low-level configuration</a>. The configured number * of bytes is used as-is, without anything like round-up to the multiple of 8 or 16, or any * other adjustment. * * @param actualChunkSize the "chunk size" in bytes * @return this builder back * @see #entries(long) * @see #maxChunksPerEntry(int) */ B actualChunkSize(int actualChunkSize); /** * Configures how many chunks a single entry, inserted into {@code ChronicleHash}es, created * by this builder, could take. If you try to insert larger entry, {@link IllegalStateException} * is fired. This is useful as self-check, that you configured chunk size right and you * keys (and values, in {@link ChronicleMap} case) take expected number of bytes. For example, * if {@link #constantKeySizeBySample(Object)} is configured or key size is statically known * to be constant (boxed primitives, data value generated implementations, {@link Byteable}s, * etc.), and the same for value objects in {@code ChronicleMap} case, max chunks per entry * is configured to 1, to ensure keys and values are actually constantly-sized. * * @param maxChunksPerEntry how many chunks a single entry could span at most * @return this builder back * @throws IllegalArgumentException if the given {@code maxChunksPerEntry} is lesser than 1 * or greater than 64 * @see #actualChunkSize(int) */ B maxChunksPerEntry(int maxChunksPerEntry); /** * Configures the target number of entries, that is going be inserted into the hash containers, * created by this builder. If {@link #maxBloatFactor(double)} is configured to {@code 1.0} * (and this is by default), this number of entries is also the maximum. If you try to insert * more entries, than the configured {@code maxBloatFactor}, multiplied by the given number of * {@code entries}, {@link IllegalStateException} <i>might</i> be thrown. * * <p>This configuration should represent the expected maximum number of entries in a stable * state, {@link #maxBloatFactor(double) maxBloatFactor} - the maximum bloat up coefficient, * during exceptional bursts. * * <p>To be more precise - try to configure the {@code entries} so, that the created hash * container is going to serve about 99% requests being less or equal than this number * of entries in size. * * <p><b>You shouldn't put additional margin over the actual target number of entries.</b> * This bad practice was popularized by {@link HashMap#HashMap(int)} and {@link * HashSet#HashSet(int)} constructors, which accept <i>capacity</i>, that should be multiplied * by <i>load factor</i> to obtain the actual maximum expected number of entries. * {@code ChronicleMap} and {@code ChronicleSet} don't have a notion of load factor. * * <p>The default target number of entries is 2^20 (~ 1 million). * * @param entries the target size of the maps or sets, created by this builder * @return this builder back * @throws IllegalArgumentException if the given {@code entries} number is non-positive * @see #maxBloatFactor(double) */ B entries(long entries); /** * Configures the maximum number of times, the hash containers, created by this builder, * are allowed to grow in size beyond the configured {@linkplain #entries(long) target number * of entries}. * * <p>{@link #entries(long)} should represent the expected maximum number of entries in a stable * state, {@code maxBloatFactor} - the maximum bloat up coefficient, during exceptional bursts. * * <p>This configuration should be used for self-checking. Even if you configure impossibly * large {@code maxBloatFactor}, the created {@code ChronicleHash}, of cause, will be still * operational, and even won't allocate any extra resources before they are actually needed. * But when the {@code ChronicleHash} grows beyond the configured {@link #entries(long)}, it * could start to serve requests progressively slower. If you insert new entries into * {@code ChronicleHash} infinitely, due to a bug in your business logic code, or the * ChronicleHash configuration, and if you configure the ChronicleHash to grow infinitely, you * will have a terribly slow and fat, but operational application, instead of a fail with * {@code IllegalStateException}, which will quickly show you, that there is a bug in you * application. * * <p>The default maximum bloat factor factor is {@code 1.0} - i. e. "no bloat is expected". * * <p>It is strongly advised not to configure {@code maxBloatFactor} to more than {@code 10.0}, * almost certainly, you either should configure {@code ChronicleHash}es completely differently, * or this data store doesn't fit to your case. * * @param maxBloatFactor the maximum number ot times, the created hash container is supposed * to bloat up beyond the {@link #entries(long)} * @return this builder back * @throws IllegalArgumentException if the given {@code maxBloatFactor} is NaN, lesser than 1.0 * or greater than 1000.0 (one thousand) * @see #entries(long) */ B maxBloatFactor(double maxBloatFactor); /** * In addition to {@link #maxBloatFactor(double) maxBloatFactor(1.0)}, that <i>does not</i> * guarantee that segments won't tier (due to bad hash distribution or natural variance), * configuring {@code allowSegmentTiering(false)} makes Chronicle Hashes, created by this * builder, to throw {@code IllegalStateException} immediately when some segment overflows. * * <p>Useful exactly for testing hash distribution and variance of segment filling. * * <p>Default is {@code true}, segments are allowed to tier. * * <p>When configured to {@code false}, {@link #maxBloatFactor(double)} configuration becomes * irrelevant, because effectively no bloat is allowed. * * @param allowSegmentTiering if {@code true}, when a segment overflows a next tier * is allocated to accommodate new entries * @return this builder back */ B allowSegmentTiering(boolean allowSegmentTiering); /** * Configures probabilistic fraction of segments, which shouldn't become tiered, if Chronicle * Hash size is {@link #entries(long)}, assuming hash code distribution of the keys, inserted * into configured Chronicle Hash, is good. * * <p>The last caveat means that the configured percentile and affects segment size relying on * Poisson distribution law, if inserted entries (keys) fall into all segments randomly. If * e. g. the keys, inserted into the Chronicle Hash, are purposely selected to collide by * a certain range of hash code bits, so that they all fall into the same segment (a DOS * attacker might do this), this segment is obviously going to be tiered. * * <p>This configuration affects the actual number of segments, if {@link #entries(long)} and * {@link #entriesPerSegment(long)} or {@link #actualChunksPerSegmentTier(long)} are configured. * It affects the actual number of entries per segment/chunks per segment tier, if {@link * #entries(long)} and {@link #actualSegments(int)} are configured. If all 4 configurations, * mentioned in this paragraph, are specified, {@code nonTieredSegmentsPercentile} doesn't make * any effect. * * <p>Default value is 0.99999, i. e. if hash code distribution of the keys is good, only one * segment of 100K is tiered on average. If your segment size is small and you want to improve * memory footprint of Chronicle Hash (probably compromising latency percentiles), you might * want to configure more "relaxed" value, e. g. 0.99. * * @param nonTieredSegmentsPercentile Fraction of segments which shouldn't be tiered * @return this builder back * @throws IllegalArgumentException if {@code nonTieredSegmentsPercentile} is out of (0.5, 1.0) * range (both bounds are excluded) */ B nonTieredSegmentsPercentile(double nonTieredSegmentsPercentile); /** * Configures the actual maximum number entries, that could be inserted into any single segment * of the hash containers, created by this builder. Configuring both the actual number of * entries per segment and {@linkplain #actualSegments(int) actual segments} replaces a single * {@link #entries(long)} configuration. * * <p>This is a <a href="#low-level-config">low-level configuration</a>. * * @param entriesPerSegment the actual maximum number entries per segment in the * hash containers, created by this builder * @return this builder back * @see #entries(long) * @see #actualSegments(int) */ B entriesPerSegment(long entriesPerSegment); /** * Configures the actual number of chunks, that will be reserved for any single segment tier of * the hash containers, created by this builder. This configuration is a lower-level version of * {@link #entriesPerSegment(long)}. Makes sense only if {@link #actualChunkSize(int)}, * {@link #actualSegments(int)} and {@link #entriesPerSegment(long)} are also configured * manually. * * @param actualChunksPerSegmentTier the actual number of chunks, reserved per segment tier in * the hash containers, created by this builder * @return this builder back */ B actualChunksPerSegmentTier(long actualChunksPerSegmentTier); /** * Configures the actual number of segments in the hash containers, created by this builder. * With {@linkplain #entriesPerSegment(long) actual number of segments}, this * configuration replaces a single {@link #entries(long)} call. * * <p>This is a <a href="#low-level-config">low-level configuration</a>. The configured number * is used as-is, without anything like round-up to the closest power of 2. * * @param actualSegments the actual number of segments in hash containers, created by * this builder * @return this builder back * @see #minSegments(int) * @see #entriesPerSegment(long) */ B actualSegments(int actualSegments); /** * Configures the {@code DataAccess} and {@code SizedReader} used to serialize and deserialize * keys to and from off-heap memory in hash containers, created by this builder. * * @param keyReader the new bytes → key object reader strategy * @param keyDataAccess the new strategy of accessing the keys' bytes for writing * @return this builder back * @see #keyMarshallers(SizedReader, SizedWriter) */ B keyReaderAndDataAccess(SizedReader<K> keyReader, @NotNull DataAccess<K> keyDataAccess); /** * Configures the marshallers, used to serialize/deserialize keys to/from off-heap memory in * hash containers, created by this builder. * * @param keyReader the new bytes → key object reader strategy * @param keyWriter the new key object → bytes writer strategy * @return this builder back * @see #keyReaderAndDataAccess(SizedReader, DataAccess) */ B keyMarshallers(@NotNull BytesReader<K> keyReader, @NotNull BytesWriter<? super K> keyWriter); /** * Shortcut for {@link #keyMarshallers(BytesReader, BytesWriter) * keyMarshallers(marshaller, marshaller)}. */ <M extends BytesReader<K> & BytesWriter<? super K>> B keyMarshaller(@NotNull M marshaller); /** * Configures the marshallers, used to serialize/deserialize keys to/from off-heap memory in * hash containers, created by this builder. * * @param keyReader the new bytes → key object reader strategy * @param keyWriter the new key object → bytes writer strategy * @return this builder back * @see #keyReaderAndDataAccess(SizedReader, DataAccess) */ B keyMarshallers(@NotNull SizedReader<K> keyReader, @NotNull SizedWriter<? super K> keyWriter); /** * Shortcut for {@link #keyMarshallers(SizedReader, SizedWriter) * keyMarshallers(sizedMarshaller, sizedMarshaller)}. * * @param sizedMarshaller implementation of both {@link SizedReader} and {@link SizedWriter} * interfaces * @return this builder back */ <M extends SizedReader<K> & SizedWriter<? super K>> B keyMarshaller(@NotNull M sizedMarshaller); /** * Configures the marshaller used to serialize actual key sizes to off-heap memory in hash * containers, created by this builder. * * <p>Default key size marshaller is so-called "stop bit encoding" marshalling. If {@linkplain * #constantKeySizeBySample(Object) constant key size} is configured, or defaulted if the key * type is always constant and {@code ChronicleHashBuilder} implementation knows about it, this * configuration takes no effect, because a special {@link SizeMarshaller} implementation, which * doesn't actually do any marshalling, and just returns the known constant size on {@link * SizeMarshaller#readSize(Bytes)} calls, is used instead of any {@code SizeMarshaller} * configured using this method. * * @param keySizeMarshaller the new marshaller, used to serialize actual key sizes to off-heap * memory * @return this builder back */ B keySizeMarshaller(@NotNull SizeMarshaller keySizeMarshaller); /** * Specifies whether on the current combination of platform, OS and Jvm aligned 8-byte reads * and writes are atomic or not. The default value of this configuration is {@link * net.openhft.chronicle.core.OS#is64Bit()}. * * @param aligned64BitMemoryOperationsAtomic {@code true} if aligned 8-byte memory operations * are atomic * @return this builder back */ B aligned64BitMemoryOperationsAtomic(boolean aligned64BitMemoryOperationsAtomic); /** * Configures whether hash containers, created by this builder, should compute and store entry * checksums. It is used to detect data corruption during recovery after crashes. See the * <a href="https://github.com/OpenHFT/Chronicle-Map#entry-checksums">Entry Checksums section * </a> in the Chronicle Map tutorial for more information. * * <p>By default, {@linkplain #createPersistedTo(File) persisted} hash containers, created by * {@code ChronicleMapBuilder} <i>do</i> compute and store entry checksums, but hash containers, * created in the process memory via {@link #create()} - don't. * * @param checksumEntries if entry checksums should be computed and stored * @return this builder back * @see ChecksumEntry * @see #recoverPersistedTo(File, boolean) */ B checksumEntries(boolean checksumEntries); /** * Creates a new hash container from this builder, storing it's data in off-heap memory, not * mapped to any file. On {@link ChronicleHash#close()} called on the returned container, or * after the container object is collected during GC, or on JVM shutdown the off-heap memory * used by the returned container is freed. * * @return a new off-heap hash container * @see #createPersistedTo(File) */ H create(); /** * Opens a hash container residing the specified file, or creates a new one from this builder, * if the file doesn't yet exist and maps its off-heap memory to the file. All changes to the * map are persisted to disk (this is an operating system guarantee) independently from JVM * process lifecycle. * * <p>Multiple containers could give access to the same data simultaneously, either inside a * single JVM or across processes. Access is synchronized correctly across all instances, i. e. * hash container mapping the data from the first JVM isn't able to modify the data, * concurrently accessed from the second JVM by another hash container instance, mapping the * same data. * * <p>On container's {@link ChronicleHash#close() close()} the data isn't removed, it remains on * disk and available to be opened again (given the same file name) or during different JVM * run. * * <p>This method is shortcut for {@code instance().persistedTo(file).create()}. * * @param file the file with existing hash container or a desired location of a new off-heap * persisted hash container * @return a hash container mapped to the given file * @throws NullPointerException if the given file is null * @throws IOException if any IO error, related to off-heap memory allocation or file mapping, * or establishing replication connections, occurs * @see ChronicleHash#file() * @see ChronicleHash#close() * @see #create() * @see #createOrRecoverPersistedTo(File, boolean) * @see #recoverPersistedTo(File, boolean) */ H createPersistedTo(File file) throws IOException; /** * Recovers and opens the hash container, persisted to the specified file, or creates a new one * from this builder, if the file doesn't exist yet, and maps its off-heap memory to the file. * This method is equivalent to {@link #createOrRecoverPersistedTo(File, boolean) * createOrRecoverPersistedTo(file, true)}. * * <p><b>This method couldn't be used, if the Chronicle Map was created using an older version * of the Chronicle Map library, and then {@code createOrRecoverPersistedTo()} is called with * a newer version of the Chronicle Map library.</b> In this case, {@link * #createOrRecoverPersistedTo(File, boolean) createOrRecoverPersistedTo(file, false)} should * be used. * * @param file the persistence file for existing of future hash container * @return a {@code ChronicleHash} instance, mapped to the given instance * @throws NullPointerException if the given file is null * @throws IOException if any IO error occurs on reading data from the file, or related to * off-heap memory allocation or file mapping, or establishing replication connections. Probably * the file is corrupted on OS level, and should be recovered on that level first, before * calling this procedure. * @throws ChronicleHashRecoveryFailedException if recovery is impossible * @see #createPersistedTo(File) * @see #createOrRecoverPersistedTo(File, boolean) * @see #recoverPersistedTo(File, boolean) * @see #createOrRecoverPersistedTo(File, boolean, ChronicleHashCorruption.Listener) */ H createOrRecoverPersistedTo(File file) throws IOException; /** * Recovers and opens the hash container, persisted to the specified file, or creates a new one * from this builder, if the file doesn't exist yet, and maps its off-heap memory to the file. * In other words, this methods behaves like {@link #createPersistedTo(File)}, if the given * file doesn't exist, and {@link #recoverPersistedTo(File, boolean) * recoverPersistedTo(file, sameLibraryVersion)}, if the file exists. * * <p>The difference between this method and {@link #createOrRecoverPersistedTo(File, boolean, * ChronicleHashCorruption.Listener)} is that this method just logs the encountered corruptions, * instead of passing them to the specified corruption listener. * * @param file the persistence file for existing of future hash container * @param sameLibraryVersion if this builder is configured with the same configurations, as the * builder, which created the Chronicle Map in the given file initially, and <b>the same version * of the Chronicle Map library was used</b>. In this case, the header of the file is overridden * (with presumably the same configurations), protecting from {@link * ChronicleHashRecoveryFailedException}, if the header is corrupted. * @return a {@code ChronicleHash} instance, mapped to the given instance * @throws NullPointerException if the given file is null * @throws IOException if any IO error occurs on reading data from the file, or related to * off-heap memory allocation or file mapping, or establishing replication connections. Probably * the file is corrupted on OS level, and should be recovered on that level first, before * calling this procedure. * @throws ChronicleHashRecoveryFailedException if recovery is impossible * @see #createPersistedTo(File) * @see #recoverPersistedTo(File, boolean) * @see #createOrRecoverPersistedTo(File, boolean, ChronicleHashCorruption.Listener) */ H createOrRecoverPersistedTo(File file, boolean sameLibraryVersion) throws IOException; /** * Recovers and opens the hash container, persisted to the specified file, or creates a new one * from this builder, if the file doesn't exist yet, and maps its off-heap memory to the file. * In other words, this methods behaves like {@link #createPersistedTo(File)}, if the given * file doesn't exist, and {@link * #recoverPersistedTo(File, boolean, ChronicleHashCorruption.Listener) * recoverPersistedTo(file, sameLibraryVersion, corruptionListener)}, if the file exists. * * <p>If this procedure encounters corruptions, it fixes them (<i>recovers</i> from them) and * notifies the provided corruption listener with the details about the corruption. See the * documentation for {@link ChronicleHashCorruption} for more information. * * @param file the persistence file for existing of future hash container * @param sameLibraryVersion if this builder is configured with the same configurations, as the * builder, which created the Chronicle Map in the given file initially, and <b>the same version * of the Chronicle Map library was used</b>. In this case, the header of the file is overridden * (with presumably the same configurations), protecting from {@link * ChronicleHashRecoveryFailedException}, if the header is corrupted. * @return a {@code ChronicleHash} instance, mapped to the given instance * @throws NullPointerException if the given file or corruptionListener is null * @throws IOException if any IO error occurs on reading data from the file, or related to * off-heap memory allocation or file mapping, or establishing replication connections. Probably * the file is corrupted on OS level, and should be recovered on that level first, before * calling this procedure. * @throws ChronicleHashRecoveryFailedException if recovery is impossible * @see #createOrRecoverPersistedTo(File, boolean) * @see #recoverPersistedTo(File, boolean) */ H createOrRecoverPersistedTo( File file, boolean sameLibraryVersion, ChronicleHashCorruption.Listener corruptionListener) throws IOException; /** * <i>Recovers</i> and opens the hash container, persisted to the specified file. This method * should be used to open a persisted Chronicle Map after an accessor process crash (that might * leave some locks "acquired" therefore some segments inaccessible), or an accessor process * external termination (that, in addition to inaccessible segments, might lead to leaks in the * Chronicle Hash memory), or a sudden power loss, or a file corruption (that, in addition to * the already mentioned consequences, might lead to data corruption, i. e. presence of entries * which were never put into the Chronicle Hash). * * <p>This method, unlike {@link #createPersistedTo(File)} or {@link * #createOrRecoverPersistedTo(File, boolean)} methods, expects that the given file already * exists. * * <p>"Recovery" of the hash container is changing the memory of the data structure so that * after the recovery the hash container is in some correct state: with "clean" locks, coherent * entry counters, not containing provably corrupt entries, etc. <i>If {@link * #checksumEntries(boolean) checksumEntries(true)} is configured for the chronicle hash * container, recovery procedure checks for each entry that the checksums is correct, otherwise * it assumes the entry is corrupt and deletes it from the Chronicle Hash.</i> See the * <a href="https://github.com/OpenHFT/Chronicle-Map#recovery">Recovery section</a> in the * Chronicle Map tutorial for more information. * * <p>The difference between this method and {@link #recoverPersistedTo(File, boolean, * ChronicleHashCorruption.Listener)} is that this method just logs the encountered corruptions, * instead of passing them to the specified corruption listener. * * <p>At the moment this method is called and executed, no other thread or process should be * mapping to the given file, and trying to access the given file. Otherwise the outcomes of * the {@code recoverPersistedTo()} call, as well as the behaviour of the concurrent thread or * process, accessing the same Chronicle Map, are unspecified: exception or error could be * thrown, the Chronicle Map persisted to the given file could be further corrupted. * * <p>It is strongly recommended to configure this builder with the same configurations, as * the builder, that created the given file for the first time, and pass {@code true} as the * {@code sameBuilderConfigAndLibraryVersion} argument <b>(another requirement is running * the same version of the Chronicle Map library)</b>. Otherwise, if the header of the given * persisted Chronicle Hash file is corrupted, this method is likely to be unable to recover and * throw {@link ChronicleHashRecoveryFailedException}, or even worse, to corrupt the file * further. Fortunately, the header should never be corrupted on an "ordinary" process * crash/termination or power loss, only on direct file corruption. * * @param file a hash container was mapped to the given file * @param sameBuilderConfigAndLibraryVersion if this builder is configured with the same * configurations, as the builder, which created the file (the persisted Chronicle Hash * instance) for the first time, and <b>with the same version of the Chronicle Map library</b>. * In this case, the header of the file is overridden (with presumably the same configurations), * protecting from {@link ChronicleHashRecoveryFailedException}, if the header is corrupted. * @return a recovered Chronicle Hash instance, mapped to the given file * @throws NullPointerException if the given file is null * @throws FileNotFoundException if the file doesn't exist * @throws IOException if any IO error occurs on reading data from the file, or related to * off-heap memory allocation or file mapping, or establishing replication connections. Probably * the file is corrupted on OS level, and should be recovered on that level first, before * calling this procedure. * @throws ChronicleHashRecoveryFailedException if recovery is impossible * @see #createOrRecoverPersistedTo(File, boolean) * @see #createPersistedTo(File) * @see #recoverPersistedTo(File, boolean, ChronicleHashCorruption.Listener) */ H recoverPersistedTo(File file, boolean sameBuilderConfigAndLibraryVersion) throws IOException; /** * <i>Recovers</i> and opens the hash container, persisted to the specified file. This method * should be used to open a persisted Chronicle Map after an accessor process crash (that might * leave some locks "acquired" therefore some segments inaccessible), or an accessor process * external termination (that, in addition to inaccessible segments, might lead to leaks in the * Chronicle Hash memory), or a sudden power loss, or a file corruption (that, in addition to * the already mentioned consequences, might lead to data corruption, i. e. presence of entries * which were never put into the Chronicle Hash). * * <p>This method, unlike {@link #createPersistedTo(File)} or {@link * #createOrRecoverPersistedTo(File, boolean, ChronicleHashCorruption.Listener)} methods, * expects that the given file already exists. * * <p>"Recovery" of the hash container is changing the memory of the data structure so that * after the recovery the hash container is in some correct state: with "clean" locks, coherent * entry counters, not containing provably corrupt entries, etc. <i>If {@link * #checksumEntries(boolean) checksumEntries(true)} is configured for the chronicle hash * container, recovery procedure checks for each entry that the checksums is correct, otherwise * it assumes the entry is corrupt and deletes it from the Chronicle Hash.</i> See the * <a href="https://github.com/OpenHFT/Chronicle-Map#recovery">Recovery section</a> in the * Chronicle Map tutorial for more information. * * <p>If this procedure encounters corruptions, it fixes them (<i>recovers</i> from them) and * notifies the provided corruption listener with the details about the corruption. See the * documentation for {@link ChronicleHashCorruption} for more information. * * <p>At the moment this method is called and executed, no other thread or process should be * mapping to the given file, and trying to access the given file. Otherwise the outcomes of * the {@code recoverPersistedTo()} call, as well as the behaviour of the concurrent thread or * process, accessing the same Chronicle Map, are unspecified: exception or error could be * thrown, the Chronicle Map persisted to the given file could be further corrupted. * * @param file a hash container was mapped to the given file * @param sameBuilderConfigAndLibraryVersion if this builder is configured with the same * configurations, as the builder, which created the file (the persisted Chronicle Hash * instance) for the first time, and <b>with the same version of the Chronicle Map library</b>. * In this case, the header of the file is overridden (with presumably the same configurations), * protecting from {@link ChronicleHashRecoveryFailedException}, if the header is corrupted. * @return a recovered Chronicle Hash instance, mapped to the given file * @throws NullPointerException if the given file or corruptionListener is null * @throws FileNotFoundException if the file doesn't exist * @throws IOException if any IO error occurs on reading data from the file, or related to * off-heap memory allocation or file mapping, or establishing replication connections. Probably * the file is corrupted on OS level, and should be recovered on that level first, before * calling this procedure. * @throws ChronicleHashRecoveryFailedException if recovery is impossible * @see #recoverPersistedTo(File, boolean) * @see #createOrRecoverPersistedTo(File, boolean, ChronicleHashCorruption.Listener) * @see #createPersistedTo(File) */ H recoverPersistedTo( File file, boolean sameBuilderConfigAndLibraryVersion, ChronicleHashCorruption.Listener corruptionListener) throws IOException; /** * @deprecated don't use private API in the client code */ @Deprecated Object privateAPI(); }