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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.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSortedSet;
import com.google.common.collect.Lists;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/** Describes a keyspace defined in this cluster. */
public class KeyspaceMetadata {

  public static final String KS_NAME = "keyspace_name";
  private static final String DURABLE_WRITES = "durable_writes";
  private static final String STRATEGY_CLASS = "strategy_class";
  private static final String STRATEGY_OPTIONS = "strategy_options";
  private static final String REPLICATION = "replication";

  private final String name;
  private final boolean durableWrites;
  private final boolean virtual;

  private final ReplicationStrategy strategy;
  private final Map replication;

  final Map tables = new ConcurrentHashMap();
  final Map views =
      new ConcurrentHashMap();
  final Map userTypes =
      Collections.synchronizedMap(new LinkedHashMap());
  final Map functions = new ConcurrentHashMap();
  final Map aggregates =
      new ConcurrentHashMap();

  @VisibleForTesting
  @Deprecated
  KeyspaceMetadata(String name, boolean durableWrites, Map replication) {
    this(name, durableWrites, replication, false);
  }

  @VisibleForTesting
  KeyspaceMetadata(
      String name, boolean durableWrites, Map replication, boolean virtual) {
    this.name = name;
    this.durableWrites = durableWrites;
    this.replication = replication;
    this.strategy = ReplicationStrategy.create(replication);
    this.virtual = virtual;
  }

  static KeyspaceMetadata build(Row row, VersionNumber cassandraVersion) {
    if (cassandraVersion.getMajor() <= 2) {
      String name = row.getString(KS_NAME);
      boolean durableWrites = row.getBool(DURABLE_WRITES);
      Map replicationOptions;
      replicationOptions = new HashMap();
      replicationOptions.put("class", row.getString(STRATEGY_CLASS));
      replicationOptions.putAll(SimpleJSONParser.parseStringMap(row.getString(STRATEGY_OPTIONS)));
      return new KeyspaceMetadata(name, durableWrites, replicationOptions, false);
    } else {
      String name = row.getString(KS_NAME);
      boolean durableWrites = row.getBool(DURABLE_WRITES);
      return new KeyspaceMetadata(
          name, durableWrites, row.getMap(REPLICATION, String.class, String.class), false);
    }
  }

  static KeyspaceMetadata buildVirtual(Row row, VersionNumber cassandraVersion) {
    String name = row.getString(KS_NAME);
    return new KeyspaceMetadata(name, false, Collections.emptyMap(), true);
  }

  /**
   * Returns the name of this keyspace.
   *
   * @return the name of this CQL keyspace.
   */
  public String getName() {
    return name;
  }

  /**
   * Returns whether durable writes are set on this keyspace.
   *
   * @return {@code true} if durable writes are set on this keyspace (the default), {@code false}
   *     otherwise.
   */
  public boolean isDurableWrites() {
    return durableWrites;
  }

  /**
   * Returns whether or not this keyspace is a virtual keyspace
   *
   * @return {@code true} if virtual keyspace default), {@code false} otherwise.
   */
  public boolean isVirtual() {
    return virtual;
  }

  /**
   * Returns the replication options for this keyspace.
   *
   * @return a map containing the replication options for this keyspace.
   */
  public Map getReplication() {
    return Collections.unmodifiableMap(replication);
  }

  /**
   * Returns the metadata for a table contained in this keyspace.
   *
   * @param name the name of table to retrieve
   * @return the metadata for table {@code name} if it exists in this keyspace, {@code null}
   *     otherwise.
   */
  public TableMetadata getTable(String name) {
    return tables.get(Metadata.handleId(name));
  }

  TableMetadata removeTable(String table) {
    return tables.remove(table);
  }

  /**
   * Returns the tables defined in this keyspace.
   *
   * @return a collection of the metadata for the tables defined in this keyspace.
   */
  public Collection getTables() {
    return Collections.unmodifiableCollection(tables.values());
  }

  /**
   * Returns the metadata for a materialized view contained in this keyspace.
   *
   * @param name the name of materialized view to retrieve
   * @return the metadata for materialized view {@code name} if it exists in this keyspace, {@code
   *     null} otherwise.
   */
  public MaterializedViewMetadata getMaterializedView(String name) {
    return views.get(Metadata.handleId(name));
  }

  MaterializedViewMetadata removeMaterializedView(String materializedView) {
    return views.remove(materializedView);
  }

  /**
   * Returns the materialized views defined in this keyspace.
   *
   * @return a collection of the metadata for the materialized views defined in this keyspace.
   */
  public Collection getMaterializedViews() {
    return Collections.unmodifiableCollection(views.values());
  }

  /**
   * Returns the definition for a user defined type (UDT) in this keyspace.
   *
   * @param name the name of UDT definition to retrieve
   * @return the definition for {@code name} if it exists in this keyspace, {@code null} otherwise.
   */
  public UserType getUserType(String name) {
    return userTypes.get(Metadata.handleId(name));
  }

  /**
   * Returns the user types defined in this keyspace.
   *
   * @return a collection of the definition for the user types defined in this keyspace.
   */
  public Collection getUserTypes() {
    return Collections.unmodifiableCollection(userTypes.values());
  }

  UserType removeUserType(String userType) {
    return userTypes.remove(userType);
  }

  /**
   * Returns the definition of a function in this keyspace.
   *
   * @param name the name of the function.
   * @param argumentTypes the types of the function's arguments.
   * @return the function definition if it exists in this keyspace, {@code null} otherwise.
   */
  public FunctionMetadata getFunction(String name, Collection argumentTypes) {
    return functions.get(Metadata.fullFunctionName(Metadata.handleId(name), argumentTypes));
  }

  /**
   * Returns the definition of a function in this keyspace.
   *
   * @param name the name of the function.
   * @param argumentTypes the types of the function's arguments.
   * @return the function definition if it exists in this keyspace, {@code null} otherwise.
   */
  public FunctionMetadata getFunction(String name, DataType... argumentTypes) {
    return getFunction(name, Lists.newArrayList(argumentTypes));
  }

  /**
   * Returns the functions defined in this keyspace.
   *
   * @return a collection of the definition for the functions defined in this keyspace.
   */
  public Collection getFunctions() {
    return Collections.unmodifiableCollection(functions.values());
  }

  FunctionMetadata removeFunction(String fullName) {
    return functions.remove(fullName);
  }

  /**
   * Returns the definition of an aggregate in this keyspace.
   *
   * @param name the name of the aggregate.
   * @param argumentTypes the types of the aggregate's arguments.
   * @return the aggregate definition if it exists in this keyspace, {@code null} otherwise.
   */
  public AggregateMetadata getAggregate(String name, Collection argumentTypes) {
    return aggregates.get(Metadata.fullFunctionName(Metadata.handleId(name), argumentTypes));
  }

  /**
   * Returns the definition of an aggregate in this keyspace.
   *
   * @param name the name of the aggregate.
   * @param argumentTypes the types of the aggregate's arguments.
   * @return the aggregate definition if it exists in this keyspace, {@code null} otherwise.
   */
  public AggregateMetadata getAggregate(String name, DataType... argumentTypes) {
    return getAggregate(name, Lists.newArrayList(argumentTypes));
  }

  /**
   * Returns the aggregates defined in this keyspace.
   *
   * @return a collection of the definition for the aggregates defined in this keyspace.
   */
  public Collection getAggregates() {
    return Collections.unmodifiableCollection(aggregates.values());
  }

  AggregateMetadata removeAggregate(String fullName) {
    return aggregates.remove(fullName);
  }

  // comparators for ordering types in cqlsh output.

  private static final Comparator typeByName =
      new Comparator() {
        @Override
        public int compare(UserType o1, UserType o2) {
          return o1.getTypeName().compareTo(o2.getTypeName());
        }
      };

  private static final Comparator functionByName =
      new Comparator() {
        @Override
        public int compare(FunctionMetadata o1, FunctionMetadata o2) {
          return o1.getSimpleName().compareTo(o2.getSimpleName());
        }
      };

  private static final Comparator aggregateByName =
      new Comparator() {
        @Override
        public int compare(AggregateMetadata o1, AggregateMetadata o2) {
          return o1.getSimpleName().compareTo(o2.getSimpleName());
        }
      };

  /**
   * Returns a {@code String} containing CQL queries representing this keyspace and the user types
   * and tables it contains.
   *
   * 

In other words, this method returns the queries that would allow to recreate the schema of * this keyspace, along with all its user types/tables. * *

Note that the returned String is formatted to be human readable (for some definition of * human readable at least). * * @return the CQL queries representing this keyspace schema as a {code String}. */ public String exportAsString() { StringBuilder sb = new StringBuilder(); sb.append(asCQLQuery()).append('\n'); // include types, tables, views, functions and aggregates, each ordered by name, with one small // exception // being that user types are ordered topologically and then by name within same level. for (UserType udt : getSortedUserTypes()) sb.append('\n').append(udt.exportAsString()).append('\n'); for (AbstractTableMetadata tm : ImmutableSortedSet.orderedBy(AbstractTableMetadata.byNameComparator) .addAll(tables.values()) .build()) sb.append('\n').append(tm.exportAsString()).append('\n'); for (FunctionMetadata fm : ImmutableSortedSet.orderedBy(functionByName).addAll(functions.values()).build()) sb.append('\n').append(fm.exportAsString()).append('\n'); for (AggregateMetadata am : ImmutableSortedSet.orderedBy(aggregateByName).addAll(aggregates.values()).build()) sb.append('\n').append(am.exportAsString()).append('\n'); return sb.toString(); } private List getSortedUserTypes() { // rebuilds dependency tree of user types so they may be sorted within each dependency level. List unsortedTypes = new ArrayList(userTypes.values()); DirectedGraph graph = new DirectedGraph(typeByName, unsortedTypes); for (UserType from : unsortedTypes) { for (UserType to : unsortedTypes) { if (from != to && dependsOn(to, from)) graph.addEdge(from, to); } } return graph.topologicalSort(); } private boolean dependsOn(UserType udt1, UserType udt2) { for (UserType.Field field : udt1) { if (references(field.getType(), udt2)) { return true; } } return false; } private boolean references(DataType dataType, DataType udtType) { if (dataType.equals(udtType)) return true; for (DataType arg : dataType.getTypeArguments()) { if (references(arg, udtType)) return true; } if (dataType instanceof TupleType) { for (DataType arg : ((TupleType) dataType).getComponentTypes()) { if (references(arg, udtType)) return true; } } return false; } /** * Returns a CQL query representing this keyspace. * *

This method returns a single 'CREATE KEYSPACE' query with the options corresponding to this * keyspace definition. * * @return the 'CREATE KEYSPACE' query corresponding to this keyspace. * @see #exportAsString */ public String asCQLQuery() { StringBuilder sb = new StringBuilder(); if (virtual) { sb.append("/* VIRTUAL "); } else { sb.append("CREATE "); } sb.append("KEYSPACE ").append(Metadata.quoteIfNecessary(name)).append(" WITH "); sb.append("REPLICATION = { 'class' : '").append(replication.get("class")).append('\''); for (Map.Entry entry : replication.entrySet()) { if (entry.getKey().equals("class")) continue; sb.append(", '").append(entry.getKey()).append("': '").append(entry.getValue()).append('\''); } sb.append(" } AND DURABLE_WRITES = ").append(durableWrites); sb.append(';'); if (virtual) { sb.append("*/"); } return sb.toString(); } @Override public String toString() { if (virtual) { return name; } return asCQLQuery(); } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; KeyspaceMetadata that = (KeyspaceMetadata) o; if (durableWrites != that.durableWrites) return false; if (!name.equals(that.name)) return false; if (strategy != null ? !strategy.equals(that.strategy) : that.strategy != null) return false; if (!replication.equals(that.replication)) return false; return tables.equals(that.tables); } @Override public int hashCode() { int result = name.hashCode(); result = 31 * result + (durableWrites ? 1 : 0); result = 31 * result + (strategy != null ? strategy.hashCode() : 0); result = 31 * result + replication.hashCode(); result = 31 * result + tables.hashCode(); return result; } void add(TableMetadata tm) { tables.put(tm.getName(), tm); } void add(MaterializedViewMetadata view) { views.put(view.getName(), view); } void add(FunctionMetadata function) { String functionName = Metadata.fullFunctionName(function.getSimpleName(), function.getArguments().values()); functions.put(functionName, function); } void add(AggregateMetadata aggregate) { String aggregateName = Metadata.fullFunctionName(aggregate.getSimpleName(), aggregate.getArgumentTypes()); aggregates.put(aggregateName, aggregate); } void add(UserType type) { userTypes.put(type.getTypeName(), type); } ReplicationStrategy replicationStrategy() { return strategy; } }





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