bereng commented on code in PR #3095: URL: https://github.com/apache/cassandra/pull/3095#discussion_r1538723514
########## src/java/org/apache/cassandra/cql3/ColumnsExpression.java: ########## @@ -0,0 +1,574 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * 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, + * 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 org.apache.cassandra.cql3; + +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.HashSet; +import java.util.List; +import java.util.Objects; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import com.google.common.base.Joiner; +import com.google.common.collect.ImmutableList; + +import org.apache.cassandra.cql3.functions.Function; +import org.apache.cassandra.cql3.terms.Term; +import org.apache.cassandra.db.marshal.AbstractType; +import org.apache.cassandra.db.marshal.CollectionType; +import org.apache.cassandra.db.marshal.ListType; +import org.apache.cassandra.db.marshal.MapType; +import org.apache.cassandra.db.marshal.TupleType; +import org.apache.cassandra.exceptions.InvalidRequestException; +import org.apache.cassandra.schema.ColumnMetadata; +import org.apache.cassandra.schema.TableMetadata; +import org.apache.cassandra.utils.ByteBufferUtil; + +import static org.apache.cassandra.cql3.statements.RequestValidations.checkContainsNoDuplicates; +import static org.apache.cassandra.cql3.statements.RequestValidations.checkContainsOnly; +import static org.apache.cassandra.cql3.statements.RequestValidations.checkFalse; +import static org.apache.cassandra.cql3.statements.RequestValidations.checkTrue; +import static org.apache.cassandra.cql3.statements.RequestValidations.invalidRequest; + +/** + * An expression including one or several columns. + */ +public final class ColumnsExpression +{ + /** + * Represent the expression kind + */ + public enum Kind + { + /** + * Single column expression (e.g. {@code columnA}) + */ + SINGLE_COLUMN + { + @Override + void validateColumns(TableMetadata table, List<ColumnMetadata> columns) + { + } + + @Override + AbstractType<?> type(TableMetadata table, List<ColumnMetadata> columns) + { + return columns.get(0).type; + } + + @Override + String toCQLString(Stream<String> columns, String mapKey) + { + return columns.findFirst().orElseThrow(); + } + + @Override + public String toString() + { + return "single column"; + } + }, + /** + * Multi-column expression (e.g. {@code (columnA, columnB)}) + */ + MULTI_COLUMN + { + @Override + protected void validateColumns(TableMetadata table, List<ColumnMetadata> columns) + { + int previousPosition = -1; + for (int i = 0, m = columns.size(); i < m; i++) + { + ColumnMetadata column = columns.get(i); + checkTrue(column.isClusteringColumn(), "Multi-column relations can only be applied to clustering columns but was applied to: %s", column.name); + checkFalse(columns.lastIndexOf(column) != i, "Column \"%s\" appeared twice in a relation: %s", column.name, this); + + // check that no clustering columns were skipped + checkFalse(previousPosition != -1 && column.position() != previousPosition + 1, + "Clustering columns must appear in the PRIMARY KEY order in multi-column relations: %s", toCQLString(columns, null)); + + previousPosition = column.position(); + } + } + + @Override + AbstractType<?> type(TableMetadata table, List<ColumnMetadata> columns) + { + return new TupleType(columns.stream() + .map(c -> c.type) + .collect(Collectors.toList())); + } + + @Override + String toCQLString(Stream<String> columns, String mapKey) + { + return columns.collect(Collectors.joining(", ", "(", ")")); + } + + @Override + public String toString() + { + return "multi-column"; + } + }, + /** + * Token expression (e.g. {@code token(columnA, columnB)}) + */ + TOKEN + { + @Override + protected void validateColumns(TableMetadata table, List<ColumnMetadata> columns) + { + if (columns.equals(table.partitionKeyColumns())) + return; + + // If the columns do not match the partition key columns, let's try to narrow down the problem + checkTrue(new HashSet<>(columns).containsAll(table.partitionKeyColumns()), + "The token() function must be applied to all partition key components or none of them"); + + checkContainsNoDuplicates(columns, "The token() function contains duplicate partition key components"); + + checkContainsOnly(columns, table.partitionKeyColumns(), "The token() function must contains only partition key components"); + + throw invalidRequest("The token function arguments must be in the partition key order: %s", + Joiner.on(", ").join(ColumnMetadata.toIdentifiers(table.partitionKeyColumns()))); + } + + @Override + AbstractType<?> type(TableMetadata table, List<ColumnMetadata> columns) + { + return table.partitioner.getTokenValidator(); + } + + @Override + String toCQLString(Stream<String> columns, String mapKey) + { + return columns.collect(Collectors.joining(", ", "token(", ")")); + } + + @Override + public String toString() + { + return "token"; + } + }, + /** + * Map element expression (e.g. {@code columnA[?]}) + */ + MAP_ELEMENT + { + @Override + void validateColumns(TableMetadata table, List<ColumnMetadata> columns) + { + ColumnMetadata column = columns.get(0); + checkFalse(column.type instanceof ListType, "Indexes on list entries (%s[index] = value) are not supported.", column.name); + checkTrue(column.type instanceof MapType, "Column %s cannot be used as a map", column.name); + checkTrue(column.type.isMultiCell(), "Map-entry predicates on frozen map column %s are not supported", column.name); + } + + @Override + AbstractType<?> type(TableMetadata table, List<ColumnMetadata> columns) + { + return ((MapType<?, ?>) columns.get(0).type).getValuesType(); + } + + @Override + String toCQLString(Stream<String> columns, String mapKey) + { + return new StringBuilder().append(columns.findFirst().orElseThrow()) + .append('[') + .append(mapKey) + .append(']') + .toString(); + } + + @Override + public String toString() + { + return "Map element"; + } + }; + + /** + * Validates that the specified columns are valid for this kind of expression. + * @param table the table metadata + * @param columns the expression column + */ + abstract void validateColumns(TableMetadata table, List<ColumnMetadata> columns); + + /** + * Returns the expression type. + * @param table the table metadata + * @param columns the expression columns + * @return the expression type + */ + abstract AbstractType<?> type(TableMetadata table, List<ColumnMetadata> columns); + + /** + * Returns CQL representation of the expression. + * @param columns the expression's columns + * @param mapKey the key used to access the map element + * @return the CQL representation of the expression. + */ + abstract String toCQLString(Stream<String> columns, String mapKey); + + String toCQLString(List<ColumnMetadata> columns, Term mapKey) + { + String k = null; + if (this == Kind.MAP_ELEMENT) + { + CQL3Type type = ((MapType<?, ?>) columns.get(0).type).getKeysType().asCQL3Type(); + // If a Term is not terminal it can be a row marker or a function. + // We ignore the fact that it could be a function for now. + k = mapKey.isTerminal() ? type.toCQLLiteral(((Term.Terminal) mapKey).get()) : "?"; + } + + return toCQLString(columns.stream().map(c -> c.name.toCQLString()), k); + } + + String toCQLString(List<ColumnIdentifier> identifiers, Term.Raw rawMapKey) + { + String mapKey = rawMapKey == null ? null : rawMapKey.getText(); + return toCQLString(identifiers.stream().map(ColumnIdentifier::toCQLString), mapKey); + } + } + + /** + * The kind of columns expression. + */ + private final Kind kind; + + /** + * The type of this expression + */ + private final AbstractType<?> type; + + /** + * The expression columns + */ + private final List<ColumnMetadata> columns; + + /** + * The key used to access the map element if this expression is for a map element, + * {@code null} otherwise. + */ + private final Term mapKey; + + + private ColumnsExpression(Kind kind, AbstractType<?> type, List<ColumnMetadata> columns, Term mapKey) + { + this.kind = kind; + this.type = type; + this.columns = columns; + this.mapKey = mapKey; + } + + /** + * Creates an expression for a single column (e.g. {@code columnA}). + * @param column the column + * @return an expression for a single column. + */ + public static ColumnsExpression singleColumn(ColumnMetadata column) + { + return new ColumnsExpression(Kind.SINGLE_COLUMN, column.type, ImmutableList.of(column), null); + } + + /** + * Creates an expression for multi-columns (e.g. {@code (columnA, columnB)}). + * @param columns the columns + * @return an expression for multi-columns. + */ + public static ColumnsExpression multiColumns(List<ColumnMetadata> columns) + { + AbstractType<?> type = new TupleType(columns.stream() + .map(c -> c.type) + .collect(Collectors.toList())); + return new ColumnsExpression(Kind.MULTI_COLUMN, type, ImmutableList.copyOf(columns), null); + } + + /** + * Returns the first column metadata. + * @return the first column metadata. + */ + public ColumnMetadata firstColumn() + { + return columns().get(0); + } + + /** + * Returns the last column metadata. + * @return the last column metadata. + */ + public ColumnMetadata lastColumn() + { + List<ColumnMetadata> columns = columns(); Review Comment: Unnecessary? -- This is an automated message from the Apache Git Service. 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