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* to you 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,
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* See the License for the specific language governing permissions and
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package com.datastax.oss.driver.internal.core.metadata.schema.parsing;
import com.datastax.oss.driver.api.core.CqlIdentifier;
import com.datastax.oss.driver.api.core.type.DataType;
import com.datastax.oss.driver.api.core.type.ListType;
import com.datastax.oss.driver.api.core.type.MapType;
import com.datastax.oss.driver.api.core.type.SetType;
import com.datastax.oss.driver.api.core.type.TupleType;
import com.datastax.oss.driver.api.core.type.UserDefinedType;
import com.datastax.oss.driver.internal.core.adminrequest.AdminRow;
import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
import com.datastax.oss.driver.internal.core.type.DefaultUserDefinedType;
import com.datastax.oss.driver.internal.core.util.DirectedGraph;
import com.datastax.oss.driver.shaded.guava.common.annotations.VisibleForTesting;
import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableList;
import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableMap;
import com.datastax.oss.driver.shaded.guava.common.collect.Lists;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import net.jcip.annotations.ThreadSafe;
@ThreadSafe
public class UserDefinedTypeParser {
private final DataTypeParser dataTypeParser;
private final InternalDriverContext context;
public UserDefinedTypeParser(DataTypeParser dataTypeParser, InternalDriverContext context) {
this.dataTypeParser = dataTypeParser;
this.context = context;
}
/**
* Contrary to other element parsers, this one processes all the types of a keyspace in one go.
* UDTs can depend on each other, but the system table returns them in alphabetical order. In
* order to properly build the definitions, we need to do a topological sort of the rows first, so
* that each type is parsed after its dependencies.
*/
public Map parse(
Collection typeRows, CqlIdentifier keyspaceId) {
if (typeRows.isEmpty()) {
return Collections.emptyMap();
} else {
Map types = new LinkedHashMap<>();
for (AdminRow row : topologicalSort(typeRows, keyspaceId)) {
UserDefinedType type = parseType(row, keyspaceId, types);
types.put(type.getName(), type);
}
return ImmutableMap.copyOf(types);
}
}
@VisibleForTesting
Map parse(CqlIdentifier keyspaceId, AdminRow... typeRows) {
return parse(Arrays.asList(typeRows), keyspaceId);
}
private List topologicalSort(Collection typeRows, CqlIdentifier keyspaceId) {
if (typeRows.size() == 1) {
AdminRow row = typeRows.iterator().next();
return Collections.singletonList(row);
} else {
DirectedGraph graph = new DirectedGraph<>(typeRows);
for (AdminRow dependent : typeRows) {
for (AdminRow dependency : typeRows) {
if (dependent != dependency && dependsOn(dependent, dependency, keyspaceId)) {
// Edges mean "is depended upon by"; we want the types with no dependencies to come
// first in the sort.
graph.addEdge(dependency, dependent);
}
}
}
return graph.topologicalSort();
}
}
private boolean dependsOn(AdminRow dependent, AdminRow dependency, CqlIdentifier keyspaceId) {
CqlIdentifier dependencyId = CqlIdentifier.fromInternal(dependency.getString("type_name"));
for (String fieldTypeName : dependent.getListOfString("field_types")) {
DataType fieldType = dataTypeParser.parse(keyspaceId, fieldTypeName, null, context);
if (references(fieldType, dependencyId)) {
return true;
}
}
return false;
}
private boolean references(DataType dependent, CqlIdentifier dependency) {
if (dependent instanceof UserDefinedType) {
UserDefinedType userType = (UserDefinedType) dependent;
return userType.getName().equals(dependency);
} else if (dependent instanceof ListType) {
ListType listType = (ListType) dependent;
return references(listType.getElementType(), dependency);
} else if (dependent instanceof SetType) {
SetType setType = (SetType) dependent;
return references(setType.getElementType(), dependency);
} else if (dependent instanceof MapType) {
MapType mapType = (MapType) dependent;
return references(mapType.getKeyType(), dependency)
|| references(mapType.getValueType(), dependency);
} else if (dependent instanceof TupleType) {
TupleType tupleType = (TupleType) dependent;
for (DataType componentType : tupleType.getComponentTypes()) {
if (references(componentType, dependency)) {
return true;
}
}
}
return false;
}
private UserDefinedType parseType(
AdminRow row,
CqlIdentifier keyspaceId,
Map userDefinedTypes) {
// Cassandra < 3.0:
// CREATE TABLE system.schema_usertypes (
// keyspace_name text,
// type_name text,
// field_names list,
// field_types list,
// PRIMARY KEY (keyspace_name, type_name)
// ) WITH CLUSTERING ORDER BY (type_name ASC)
//
// Cassandra >= 3.0:
// CREATE TABLE system_schema.types (
// keyspace_name text,
// type_name text,
// field_names frozen>,
// field_types frozen>,
// PRIMARY KEY (keyspace_name, type_name)
// ) WITH CLUSTERING ORDER BY (type_name ASC)
CqlIdentifier name = CqlIdentifier.fromInternal(row.getString("type_name"));
List fieldNames =
ImmutableList.copyOf(
Lists.transform(row.getListOfString("field_names"), CqlIdentifier::fromInternal));
List fieldTypes =
dataTypeParser.parse(
keyspaceId, row.getListOfString("field_types"), userDefinedTypes, context);
return new DefaultUserDefinedType(keyspaceId, name, false, fieldNames, fieldTypes, context);
}
}