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A driver for Scylla and Apache Cassandra 1.2+ that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol.

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/*
 * Copyright DataStax, Inc.
 *
 * 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
 *
 * 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 com.datastax.driver.core;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import io.netty.util.collection.IntObjectHashMap;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.ReentrantLock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Keeps metadata on the connected cluster, including known nodes and schema definitions. */
public class Metadata {

  private static final Logger logger = LoggerFactory.getLogger(Metadata.class);

  final Cluster.Manager cluster;
  volatile String clusterName;
  volatile String partitioner;
  private final ConcurrentMap hosts =
      new ConcurrentHashMap();
  final ConcurrentMap keyspaces =
      new ConcurrentHashMap();
  private volatile TokenMap tokenMap;

  final ReentrantLock lock = new ReentrantLock();

  // See https://github.com/apache/cassandra/blob/trunk/doc/cql3/CQL.textile#appendixA
  private static final IntObjectHashMap> RESERVED_KEYWORDS =
      indexByCaseInsensitiveHash(
          "add",
          "allow",
          "alter",
          "and",
          "any",
          "apply",
          "asc",
          "authorize",
          "batch",
          "begin",
          "by",
          "columnfamily",
          "create",
          "delete",
          "desc",
          "drop",
          "each_quorum",
          "from",
          "grant",
          "in",
          "index",
          "inet",
          "infinity",
          "insert",
          "into",
          "keyspace",
          "keyspaces",
          "limit",
          "local_one",
          "local_quorum",
          "modify",
          "nan",
          "norecursive",
          "of",
          "on",
          "one",
          "order",
          "password",
          "primary",
          "quorum",
          "rename",
          "revoke",
          "schema",
          "select",
          "set",
          "table",
          "to",
          "token",
          "three",
          "truncate",
          "two",
          "unlogged",
          "update",
          "use",
          "using",
          "where",
          "with");

  Metadata(Cluster.Manager cluster) {
    this.cluster = cluster;
  }

  // rebuilds the token map with the current hosts, typically when refreshing schema metadata
  void rebuildTokenMap() {
    lock.lock();
    try {
      if (tokenMap == null) return;
      this.tokenMap =
          TokenMap.build(
              tokenMap.factory,
              tokenMap.primaryToTokens,
              keyspaces.values(),
              tokenMap.ring,
              tokenMap.tokenRanges,
              tokenMap.tokenToPrimary);
    } finally {
      lock.unlock();
    }
  }

  // rebuilds the token map for a new set of hosts, typically when refreshing nodes list
  void rebuildTokenMap(Token.Factory factory, Map> allTokens) {
    lock.lock();
    try {
      this.tokenMap = TokenMap.build(factory, allTokens, keyspaces.values());
    } finally {
      lock.unlock();
    }
  }

  Host newHost(InetSocketAddress address) {
    return new Host(address, cluster.convictionPolicyFactory, cluster);
  }

  /**
   * @return the previous host associated with this socket address, or {@code null} if there was no
   *     such host.
   */
  Host addIfAbsent(Host host) {
    return hosts.putIfAbsent(host.getSocketAddress(), host);
  }

  boolean remove(Host host) {
    return hosts.remove(host.getSocketAddress()) != null;
  }

  Host getHost(InetSocketAddress address) {
    return hosts.get(address);
  }

  // For internal use only
  Collection allHosts() {
    return hosts.values();
  }

  /*
   * Deal with case sensitivity for a given element id (keyspace, table, column, etc.)
   *
   * This method is used to convert identifiers provided by the client (through methods such as getKeyspace(String)),
   * to the format used internally by the driver.
   *
   * We expect client-facing APIs to behave like cqlsh, that is:
   * - identifiers that are mixed-case or contain special characters should be quoted.
   * - unquoted identifiers will be lowercased: getKeyspace("Foo") will look for a keyspace named "foo"
   */
  static String handleId(String id) {
    // Shouldn't really happen for this method, but no reason to fail here
    if (id == null) return null;

    boolean isAlphanumericLowCase = true;
    boolean isAlphanumeric = true;
    for (int i = 0; i < id.length(); i++) {
      char c = id.charAt(i);
      if (c >= 65 && c <= 90) { // A-Z
        isAlphanumericLowCase = false;
      } else if (!((c >= 48 && c <= 57) // 0-9
          || (c == 95) // _ (underscore)
          || (c >= 97 && c <= 122) // a-z
      )) {
        isAlphanumeric = false;
        isAlphanumericLowCase = false;
        break;
      }
    }

    if (isAlphanumericLowCase) {
      return id;
    }
    if (isAlphanumeric) {
      return id.toLowerCase();
    }

    // Check if it's enclosed in quotes. If it is, remove them and unescape internal double quotes
    return ParseUtils.unDoubleQuote(id);
  }

  /**
   * Quotes a CQL identifier if necessary.
   *
   * 

This is similar to {@link #quote(String)}, except that it won't quote the input string if it * can safely be used as-is. For example: * *

    *
  • {@code quoteIfNecessary("foo").equals("foo")} (no need to quote). *
  • {@code quoteIfNecessary("Foo").equals("\"Foo\"")} (identifier is mixed case so case * sensitivity is required) *
  • {@code quoteIfNecessary("foo bar").equals("\"foo bar\"")} (identifier contains special * characters) *
  • {@code quoteIfNecessary("table").equals("\"table\"")} (identifier is a reserved CQL * keyword) *
* * @param id the "internal" form of the identifier. That is, the identifier as it would appear in * Cassandra system tables (such as {@code system_schema.tables}, {@code * system_schema.columns}, etc.) * @return the identifier as it would appear in a CQL query string. This is also how you need to * pass it to public driver methods, such as {@link #getKeyspace(String)}. */ public static String quoteIfNecessary(String id) { return needsQuote(id) ? quote(id) : id; } /** * We don't need to escape an identifier if it matches non-quoted CQL3 ids ([a-z][a-z0-9_]*), and * if it's not a CQL reserved keyword. * *

When 'Migrating from compact storage' after DROP COMPACT STORAGE on the table, it can have a * column with an empty name. (See JAVA-2174 for the reference) For that case, we need to escape * empty column name. */ private static boolean needsQuote(String s) { // this method should only be called for C*-provided identifiers, // so we expect it to be non-null assert s != null; if (s.isEmpty()) return true; char c = s.charAt(0); if (!(c >= 97 && c <= 122)) // a-z return true; for (int i = 1; i < s.length(); i++) { c = s.charAt(i); if (!((c >= 48 && c <= 57) // 0-9 || (c == 95) // _ || (c >= 97 && c <= 122) // a-z )) { return true; } } return isReservedCqlKeyword(s); } /** * Builds the internal name of a function/aggregate, which is similar, but not identical, to the * function/aggregate signature. This is only used to generate keys for internal metadata maps * (KeyspaceMetadata.functions and. KeyspaceMetadata.aggregates). Note that if simpleName comes * from the user, the caller must call handleId on it before passing it to this method. Note that * this method does not necessarily generates a valid CQL function signature. Note that * argumentTypes can be either a list of strings (schema change events) or a list of DataTypes * (function lookup from client code). This method must ensure that both cases produce the same * identifier. */ static String fullFunctionName(String simpleName, Collection argumentTypes) { StringBuilder sb = new StringBuilder(simpleName); sb.append('('); boolean first = true; for (Object argumentType : argumentTypes) { if (first) first = false; else sb.append(','); // user types must be represented by their names only, // without keyspace prefix, because that's how // they appear in a schema change event (in targetSignature) if (argumentType instanceof UserType) { UserType userType = (UserType) argumentType; String typeName = Metadata.quoteIfNecessary(userType.getTypeName()); sb.append(typeName); } else { sb.append(argumentType); } } sb.append(')'); return sb.toString(); } /** * Quote a keyspace, table or column identifier to make it case sensitive. * *

CQL identifiers, including keyspace, table and column ones, are case insensitive by default. * Case sensitive identifiers can however be provided by enclosing the identifier in double quotes * (see the CQL * documentation for details). If you are using case sensitive identifiers, this method can be * used to enclose such identifiers in double quotes, making them case sensitive. * *

Note that reserved CQL * keywords should also be quoted. You can check if a given identifier is a reserved keyword * by calling {@link #isReservedCqlKeyword(String)}. * * @param id the keyspace or table identifier. * @return {@code id} enclosed in double-quotes, for use in methods like {@link #getReplicas}, * {@link #getKeyspace}, {@link KeyspaceMetadata#getTable} or even {@link * Cluster#connect(String)}. */ public static String quote(String id) { return ParseUtils.doubleQuote(id); } /** * Checks whether an identifier is a known reserved CQL keyword or not. * *

The check is case-insensitive, i.e., the word "{@code KeYsPaCe}" would be considered as a * reserved CQL keyword just as "{@code keyspace}". * *

Note: The list of reserved CQL keywords is subject to change in future versions of * Cassandra. As a consequence, this method is provided solely as a convenience utility and should * not be considered as an authoritative source of truth for checking reserved CQL keywords. * * @param id the identifier to check; should not be {@code null}. * @return {@code true} if the given identifier is a known reserved CQL keyword, {@code false} * otherwise. */ public static boolean isReservedCqlKeyword(String id) { if (id == null) { return false; } int hash = caseInsensitiveHash(id); List keywords = RESERVED_KEYWORDS.get(hash); if (keywords == null) { return false; } else { for (char[] keyword : keywords) { if (equalsIgnoreCaseAscii(id, keyword)) { return true; } } return false; } } private static int caseInsensitiveHash(String str) { int hashCode = 17; for (int i = 0; i < str.length(); i++) { char c = toLowerCaseAscii(str.charAt(i)); hashCode = 31 * hashCode + c; } return hashCode; } // keyword is expected as a second argument always in low case private static boolean equalsIgnoreCaseAscii(String str1, char[] str2LowCase) { if (str1.length() != str2LowCase.length) return false; for (int i = 0; i < str1.length(); i++) { char c1 = str1.charAt(i); char c2Low = str2LowCase[i]; if (c1 == c2Low) { continue; } char low1 = toLowerCaseAscii(c1); if (low1 == c2Low) { continue; } return false; } return true; } private static char toLowerCaseAscii(char c) { if (c >= 65 && c <= 90) { // A-Z c ^= 0x20; // convert to low case } return c; } private static IntObjectHashMap> indexByCaseInsensitiveHash(String... words) { IntObjectHashMap> result = new IntObjectHashMap>(); for (String word : words) { char[] wordAsCharArray = word.toLowerCase().toCharArray(); int hash = caseInsensitiveHash(word); List list = result.get(hash); if (list == null) { list = new ArrayList(); result.put(hash, list); } list.add(wordAsCharArray); } return result; } /** * Returns the token ranges that define data distribution in the ring. * *

Note that this information is refreshed asynchronously by the control connection, when * schema or ring topology changes. It might occasionally be stale. * * @return the token ranges. Note that the result might be stale or empty if metadata was * explicitly disabled with {@link QueryOptions#setMetadataEnabled(boolean)}. */ public Set getTokenRanges() { TokenMap current = tokenMap; return (current == null) ? Collections.emptySet() : current.tokenRanges; } /** * Returns the token ranges that are replicated on the given host, for the given keyspace. * *

Note that this information is refreshed asynchronously by the control connection, when * schema or ring topology changes. It might occasionally be stale (or even empty). * * @param keyspace the name of the keyspace to get token ranges for. * @param host the host. * @return the (immutable) set of token ranges for {@code host} as known by the driver. Note that * the result might be stale or empty if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)}. */ public Set getTokenRanges(String keyspace, Host host) { keyspace = handleId(keyspace); TokenMap current = tokenMap; if (current == null) { return Collections.emptySet(); } else { Map> dcRanges = current.hostsToRangesByKeyspace.get(keyspace); if (dcRanges == null) { return Collections.emptySet(); } else { Set ranges = dcRanges.get(host); return (ranges == null) ? Collections.emptySet() : ranges; } } } /** * Returns the set of hosts that are replica for a given partition key. * *

Note that this information is refreshed asynchronously by the control connection, when * schema or ring topology changes. It might occasionally be stale (or even empty). * * @param keyspace the name of the keyspace to get replicas for. * @param partitionKey the partition key for which to find the set of replica. * @return the (immutable) set of replicas for {@code partitionKey} as known by the driver. Note * that the result might be stale or empty if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)}. */ public Set getReplicas(String keyspace, ByteBuffer partitionKey) { keyspace = handleId(keyspace); TokenMap current = tokenMap; if (current == null) { return Collections.emptySet(); } else { Set hosts = current.getReplicas(keyspace, current.factory.hash(partitionKey)); return hosts == null ? Collections.emptySet() : hosts; } } /** * Returns the set of hosts that are replica for a given token range. * *

Note that it is assumed that the input range does not overlap across multiple host ranges. * If the range extends over multiple hosts, it only returns the replicas for those hosts that are * replicas for the last token of the range. This behavior may change in a future release, see JAVA-1355. * *

Also note that this information is refreshed asynchronously by the control connection, when * schema or ring topology changes. It might occasionally be stale (or even empty). * * @param keyspace the name of the keyspace to get replicas for. * @param range the token range. * @return the (immutable) set of replicas for {@code range} as known by the driver. Note that the * result might be stale or empty if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)}. */ public Set getReplicas(String keyspace, TokenRange range) { keyspace = handleId(keyspace); TokenMap current = tokenMap; if (current == null) { return Collections.emptySet(); } else { Set hosts = current.getReplicas(keyspace, range.getEnd()); return hosts == null ? Collections.emptySet() : hosts; } } /** * The Cassandra name for the cluster connect to. * * @return the Cassandra name for the cluster connect to. */ public String getClusterName() { return clusterName; } /** * The partitioner in use as reported by the Cassandra nodes. * * @return the partitioner in use as reported by the Cassandra nodes. */ public String getPartitioner() { return partitioner; } /** * Returns the known hosts of this cluster. * * @return A set will all the know host of this cluster. */ public Set getAllHosts() { return new HashSet(allHosts()); } /** * Checks whether hosts that are currently up agree on the schema definition. * *

This method performs a one-time check only, without any form of retry; therefore {@link * Cluster.Builder#withMaxSchemaAgreementWaitSeconds(int)} does not apply in this case. * * @return {@code true} if all hosts agree on the schema; {@code false} if they don't agree, or if * the check could not be performed (for example, if the control connection is down). */ public boolean checkSchemaAgreement() { try { return cluster.controlConnection.checkSchemaAgreement(); } catch (Exception e) { logger.warn("Error while checking schema agreement", e); return false; } } /** * Returns the metadata of a keyspace given its name. * * @param keyspace the name of the keyspace for which metadata should be returned. * @return the metadata of the requested keyspace or {@code null} if {@code keyspace} is not a * known keyspace. Note that the result might be stale or null if metadata was explicitly * disabled with {@link QueryOptions#setMetadataEnabled(boolean)}. */ public KeyspaceMetadata getKeyspace(String keyspace) { return keyspaces.get(handleId(keyspace)); } KeyspaceMetadata removeKeyspace(String keyspace) { KeyspaceMetadata removed = keyspaces.remove(keyspace); if (tokenMap != null) tokenMap.tokenToHostsByKeyspace.remove(keyspace); return removed; } /** * Returns a list of all the defined keyspaces. * * @return a list of all the defined keyspaces. Note that the result might be stale or empty if * metadata was explicitly disabled with {@link QueryOptions#setMetadataEnabled(boolean)}. */ public List getKeyspaces() { return new ArrayList(keyspaces.values()); } /** * Returns a {@code String} containing CQL queries representing the schema of this cluster. * *

In other words, this method returns the queries that would allow to recreate the schema of * this cluster. * *

Note that the returned String is formatted to be human readable (for some definition of * human readable at least). * *

It might be stale or empty if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)}. * * @return the CQL queries representing this cluster schema as a {code String}. */ public String exportSchemaAsString() { StringBuilder sb = new StringBuilder(); for (KeyspaceMetadata ksm : keyspaces.values()) sb.append(ksm.exportAsString()).append('\n'); return sb.toString(); } /** * Creates a tuple type given a list of types. * * @param types the types for the tuple type. * @return the newly created tuple type. */ public TupleType newTupleType(DataType... types) { return newTupleType(Arrays.asList(types)); } /** * Creates a tuple type given a list of types. * * @param types the types for the tuple type. * @return the newly created tuple type. */ public TupleType newTupleType(List types) { return new TupleType( types, cluster.protocolVersion(), cluster.configuration.getCodecRegistry()); } /** * Builds a new {@link Token} from its string representation, according to the partitioner * reported by the Cassandra nodes. * * @param tokenStr the string representation. * @return the token. * @throws IllegalStateException if the token factory was not initialized. This would typically * happen if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)} before startup. */ public Token newToken(String tokenStr) { TokenMap current = tokenMap; if (current == null) throw new IllegalStateException( "Token factory not set. This should only happen if metadata was explicitly disabled"); return current.factory.fromString(tokenStr); } /** * Builds a new {@link Token} from a partition key. * * @param components the components of the partition key, in their serialized form (obtained with * {@link TypeCodec#serialize(Object, ProtocolVersion)}). * @return the token. * @throws IllegalStateException if the token factory was not initialized. This would typically * happen if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)} before startup. */ public Token newToken(ByteBuffer... components) { TokenMap current = tokenMap; if (current == null) throw new IllegalStateException( "Token factory not set. This should only happen if metadata was explicitly disabled"); return current.factory.hash(SimpleStatement.compose(components)); } /** * Builds a new {@link TokenRange}. * * @param start the start token. * @param end the end token. * @return the range. * @throws IllegalStateException if the token factory was not initialized. This would typically * happen if metadata was explicitly disabled with {@link * QueryOptions#setMetadataEnabled(boolean)} before startup. */ public TokenRange newTokenRange(Token start, Token end) { TokenMap current = tokenMap; if (current == null) throw new IllegalStateException( "Token factory not set. This should only happen if metadata was explicitly disabled"); return new TokenRange(start, end, current.factory); } Token.Factory tokenFactory() { TokenMap current = tokenMap; return (current == null) ? null : current.factory; } void triggerOnKeyspaceAdded(KeyspaceMetadata keyspace) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onKeyspaceAdded(keyspace); } } void triggerOnKeyspaceChanged(KeyspaceMetadata current, KeyspaceMetadata previous) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onKeyspaceChanged(current, previous); } } void triggerOnKeyspaceRemoved(KeyspaceMetadata keyspace) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onKeyspaceRemoved(keyspace); } } void triggerOnTableAdded(TableMetadata table) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onTableAdded(table); } } void triggerOnTableChanged(TableMetadata current, TableMetadata previous) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onTableChanged(current, previous); } } void triggerOnTableRemoved(TableMetadata table) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onTableRemoved(table); } } void triggerOnUserTypeAdded(UserType type) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onUserTypeAdded(type); } } void triggerOnUserTypeChanged(UserType current, UserType previous) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onUserTypeChanged(current, previous); } } void triggerOnUserTypeRemoved(UserType type) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onUserTypeRemoved(type); } } void triggerOnFunctionAdded(FunctionMetadata function) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onFunctionAdded(function); } } void triggerOnFunctionChanged(FunctionMetadata current, FunctionMetadata previous) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onFunctionChanged(current, previous); } } void triggerOnFunctionRemoved(FunctionMetadata function) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onFunctionRemoved(function); } } void triggerOnAggregateAdded(AggregateMetadata aggregate) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onAggregateAdded(aggregate); } } void triggerOnAggregateChanged(AggregateMetadata current, AggregateMetadata previous) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onAggregateChanged(current, previous); } } void triggerOnAggregateRemoved(AggregateMetadata aggregate) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onAggregateRemoved(aggregate); } } void triggerOnMaterializedViewAdded(MaterializedViewMetadata view) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onMaterializedViewAdded(view); } } void triggerOnMaterializedViewChanged( MaterializedViewMetadata current, MaterializedViewMetadata previous) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onMaterializedViewChanged(current, previous); } } void triggerOnMaterializedViewRemoved(MaterializedViewMetadata view) { for (SchemaChangeListener listener : cluster.schemaChangeListeners) { listener.onMaterializedViewRemoved(view); } } private static class TokenMap { private final Token.Factory factory; private final Map> primaryToTokens; private final Map>> tokenToHostsByKeyspace; private final Map>> hostsToRangesByKeyspace; private final List ring; private final Set tokenRanges; private final Map tokenToPrimary; private TokenMap( Token.Factory factory, List ring, Set tokenRanges, Map tokenToPrimary, Map> primaryToTokens, Map>> tokenToHostsByKeyspace, Map>> hostsToRangesByKeyspace) { this.factory = factory; this.ring = ring; this.tokenRanges = tokenRanges; this.tokenToPrimary = tokenToPrimary; this.primaryToTokens = primaryToTokens; this.tokenToHostsByKeyspace = tokenToHostsByKeyspace; this.hostsToRangesByKeyspace = hostsToRangesByKeyspace; for (Map.Entry> entry : primaryToTokens.entrySet()) { Host host = entry.getKey(); host.setTokens(ImmutableSet.copyOf(entry.getValue())); } } private static TokenMap build( Token.Factory factory, Map> allTokens, Collection keyspaces) { Map tokenToPrimary = new HashMap(); Set allSorted = new TreeSet(); for (Map.Entry> entry : allTokens.entrySet()) { Host host = entry.getKey(); for (Token t : entry.getValue()) { try { allSorted.add(t); tokenToPrimary.put(t, host); } catch (IllegalArgumentException e) { // If we failed parsing that token, skip it } } } List ring = new ArrayList(allSorted); Set tokenRanges = makeTokenRanges(ring, factory); return build(factory, allTokens, keyspaces, ring, tokenRanges, tokenToPrimary); } private static TokenMap build( Token.Factory factory, Map> allTokens, Collection keyspaces, List ring, Set tokenRanges, Map tokenToPrimary) { Set hosts = allTokens.keySet(); Map>> tokenToHosts = new HashMap>>(); Map>> replStrategyToHosts = new HashMap>>(); Map>> hostsToRanges = new HashMap>>(); for (KeyspaceMetadata keyspace : keyspaces) { ReplicationStrategy strategy = keyspace.replicationStrategy(); Map> ksTokens = replStrategyToHosts.get(strategy); if (ksTokens == null) { ksTokens = (strategy == null) ? makeNonReplicatedMap(tokenToPrimary) : strategy.computeTokenToReplicaMap(keyspace.getName(), tokenToPrimary, ring); replStrategyToHosts.put(strategy, ksTokens); } tokenToHosts.put(keyspace.getName(), ksTokens); Map> ksRanges; if (ring.size() == 1) { // We forced the single range to ]minToken,minToken], make sure to use that instead of // relying on the host's token ImmutableMap.Builder> builder = ImmutableMap.builder(); for (Host host : allTokens.keySet()) builder.put(host, tokenRanges); ksRanges = builder.build(); } else { ksRanges = computeHostsToRangesMap(tokenRanges, ksTokens, hosts.size()); } hostsToRanges.put(keyspace.getName(), ksRanges); } return new TokenMap( factory, ring, tokenRanges, tokenToPrimary, allTokens, tokenToHosts, hostsToRanges); } private Set getReplicas(String keyspace, Token token) { Map> tokenToHosts = tokenToHostsByKeyspace.get(keyspace); if (tokenToHosts == null) return Collections.emptySet(); // If the token happens to be one of the "primary" tokens, get result directly Set hosts = tokenToHosts.get(token); if (hosts != null) return hosts; // Otherwise, find closest "primary" token on the ring int i = Collections.binarySearch(ring, token); if (i < 0) { i = -i - 1; if (i >= ring.size()) i = 0; } return tokenToHosts.get(ring.get(i)); } private static Map> makeNonReplicatedMap(Map input) { Map> output = new HashMap>(input.size()); for (Map.Entry entry : input.entrySet()) output.put(entry.getKey(), ImmutableSet.of(entry.getValue())); return output; } private static Set makeTokenRanges(List ring, Token.Factory factory) { ImmutableSet.Builder builder = ImmutableSet.builder(); // JAVA-684: if there is only one token, return the range ]minToken, minToken] if (ring.size() == 1) { builder.add(new TokenRange(factory.minToken(), factory.minToken(), factory)); } else { for (int i = 0; i < ring.size(); i++) { Token start = ring.get(i); Token end = ring.get((i + 1) % ring.size()); builder.add(new TokenRange(start, end, factory)); } } return builder.build(); } private static Map> computeHostsToRangesMap( Set tokenRanges, Map> ksTokens, int hostCount) { Map> builders = Maps.newHashMapWithExpectedSize(hostCount); for (TokenRange range : tokenRanges) { Set replicas = ksTokens.get(range.getEnd()); for (Host host : replicas) { ImmutableSet.Builder hostRanges = builders.get(host); if (hostRanges == null) { hostRanges = ImmutableSet.builder(); builders.put(host, hostRanges); } hostRanges.add(range); } } Map> ksRanges = Maps.newHashMapWithExpectedSize(hostCount); for (Map.Entry> entry : builders.entrySet()) { ksRanges.put(entry.getKey(), entry.getValue().build()); } return ksRanges; } } }





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