| /* |
| * 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.statements; |
| |
| import java.nio.ByteBuffer; |
| import java.util.*; |
| import java.util.concurrent.TimeUnit; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.base.MoreObjects; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.cassandra.audit.AuditLogContext; |
| import org.apache.cassandra.audit.AuditLogEntryType; |
| import org.apache.cassandra.auth.Permission; |
| import org.apache.cassandra.schema.ColumnMetadata; |
| import org.apache.cassandra.schema.Schema; |
| import org.apache.cassandra.schema.TableMetadata; |
| import org.apache.cassandra.schema.TableMetadataRef; |
| import org.apache.cassandra.cql3.*; |
| import org.apache.cassandra.cql3.functions.Function; |
| import org.apache.cassandra.cql3.restrictions.StatementRestrictions; |
| import org.apache.cassandra.cql3.selection.RawSelector; |
| import org.apache.cassandra.cql3.selection.ResultSetBuilder; |
| import org.apache.cassandra.cql3.selection.Selectable; |
| import org.apache.cassandra.cql3.selection.Selection; |
| import org.apache.cassandra.cql3.selection.Selection.Selectors; |
| import org.apache.cassandra.db.*; |
| import org.apache.cassandra.db.aggregation.AggregationSpecification; |
| import org.apache.cassandra.db.aggregation.GroupMaker; |
| import org.apache.cassandra.db.filter.*; |
| import org.apache.cassandra.db.marshal.CollectionType; |
| import org.apache.cassandra.db.marshal.CompositeType; |
| import org.apache.cassandra.db.marshal.Int32Type; |
| import org.apache.cassandra.db.marshal.UserType; |
| import org.apache.cassandra.db.partitions.PartitionIterator; |
| import org.apache.cassandra.db.rows.ComplexColumnData; |
| import org.apache.cassandra.db.rows.Row; |
| import org.apache.cassandra.db.rows.RowIterator; |
| import org.apache.cassandra.db.view.View; |
| import org.apache.cassandra.dht.AbstractBounds; |
| import org.apache.cassandra.exceptions.*; |
| import org.apache.cassandra.index.IndexRegistry; |
| import org.apache.cassandra.serializers.MarshalException; |
| import org.apache.cassandra.service.ClientState; |
| import org.apache.cassandra.service.ClientWarn; |
| import org.apache.cassandra.service.QueryState; |
| import org.apache.cassandra.service.pager.AggregationQueryPager; |
| import org.apache.cassandra.service.pager.PagingState; |
| import org.apache.cassandra.service.pager.QueryPager; |
| import org.apache.cassandra.transport.ProtocolVersion; |
| import org.apache.cassandra.transport.messages.ResultMessage; |
| import org.apache.cassandra.utils.ByteBufferUtil; |
| import org.apache.cassandra.utils.NoSpamLogger; |
| import org.apache.commons.lang3.builder.ToStringBuilder; |
| import org.apache.commons.lang3.builder.ToStringStyle; |
| |
| import static org.apache.cassandra.cql3.statements.RequestValidations.checkFalse; |
| import static org.apache.cassandra.cql3.statements.RequestValidations.checkNotNull; |
| import static org.apache.cassandra.cql3.statements.RequestValidations.checkNull; |
| import static org.apache.cassandra.cql3.statements.RequestValidations.checkTrue; |
| import static org.apache.cassandra.utils.ByteBufferUtil.UNSET_BYTE_BUFFER; |
| |
| /** |
| * Encapsulates a completely parsed SELECT query, including the target |
| * column family, expression, result count, and ordering clause. |
| * |
| * A number of public methods here are only used internally. However, |
| * many of these are made accessible for the benefit of custom |
| * QueryHandler implementations, so before reducing their accessibility |
| * due consideration should be given. |
| */ |
| public class SelectStatement implements CQLStatement.SingleKeyspaceCqlStatement |
| { |
| private static final Logger logger = LoggerFactory.getLogger(SelectStatement.class); |
| private static final NoSpamLogger noSpamLogger = NoSpamLogger.getLogger(SelectStatement.logger, 1, TimeUnit.MINUTES); |
| |
| public static final int DEFAULT_PAGE_SIZE = 10000; |
| |
| public final VariableSpecifications bindVariables; |
| public final TableMetadata table; |
| public final Parameters parameters; |
| private final Selection selection; |
| private final Term limit; |
| private final Term perPartitionLimit; |
| |
| private final StatementRestrictions restrictions; |
| |
| private final boolean isReversed; |
| |
| /** |
| * The <code>AggregationSpecification</code> used to make the aggregates. |
| */ |
| private final AggregationSpecification aggregationSpec; |
| |
| /** |
| * The comparator used to orders results when multiple keys are selected (using IN). |
| */ |
| private final Comparator<List<ByteBuffer>> orderingComparator; |
| |
| // Used by forSelection below |
| private static final Parameters defaultParameters = new Parameters(Collections.emptyMap(), |
| Collections.emptyList(), |
| false, |
| false, |
| false); |
| |
| public SelectStatement(TableMetadata table, |
| VariableSpecifications bindVariables, |
| Parameters parameters, |
| Selection selection, |
| StatementRestrictions restrictions, |
| boolean isReversed, |
| AggregationSpecification aggregationSpec, |
| Comparator<List<ByteBuffer>> orderingComparator, |
| Term limit, |
| Term perPartitionLimit) |
| { |
| this.table = table; |
| this.bindVariables = bindVariables; |
| this.selection = selection; |
| this.restrictions = restrictions; |
| this.isReversed = isReversed; |
| this.aggregationSpec = aggregationSpec; |
| this.orderingComparator = orderingComparator; |
| this.parameters = parameters; |
| this.limit = limit; |
| this.perPartitionLimit = perPartitionLimit; |
| } |
| |
| @Override |
| public List<ColumnSpecification> getBindVariables() |
| { |
| return bindVariables.getBindVariables(); |
| } |
| |
| @Override |
| public short[] getPartitionKeyBindVariableIndexes() |
| { |
| return bindVariables.getPartitionKeyBindVariableIndexes(table); |
| } |
| |
| @Override |
| public Iterable<Function> getFunctions() |
| { |
| List<Function> functions = new ArrayList<>(); |
| addFunctionsTo(functions); |
| return functions; |
| } |
| |
| private void addFunctionsTo(List<Function> functions) |
| { |
| selection.addFunctionsTo(functions); |
| restrictions.addFunctionsTo(functions); |
| |
| if (limit != null) |
| limit.addFunctionsTo(functions); |
| |
| if (perPartitionLimit != null) |
| perPartitionLimit.addFunctionsTo(functions); |
| } |
| |
| /** |
| * The columns to fetch internally for this SELECT statement (which can be more than the one selected by the |
| * user as it also include any restricted column in particular). |
| */ |
| public ColumnFilter queriedColumns() |
| { |
| return selection.newSelectors(QueryOptions.DEFAULT).getColumnFilter(); |
| } |
| |
| // Creates a simple select based on the given selection. |
| // Note that the results select statement should not be used for actual queries, but only for processing already |
| // queried data through processColumnFamily. |
| static SelectStatement forSelection(TableMetadata table, Selection selection) |
| { |
| return new SelectStatement(table, |
| VariableSpecifications.empty(), |
| defaultParameters, |
| selection, |
| StatementRestrictions.empty(StatementType.SELECT, table), |
| false, |
| null, |
| null, |
| null, |
| null); |
| } |
| |
| public ResultSet.ResultMetadata getResultMetadata() |
| { |
| return selection.getResultMetadata(); |
| } |
| |
| public void authorize(ClientState state) throws InvalidRequestException, UnauthorizedException |
| { |
| if (table.isView()) |
| { |
| TableMetadataRef baseTable = View.findBaseTable(keyspace(), columnFamily()); |
| if (baseTable != null) |
| state.ensureTablePermission(baseTable, Permission.SELECT); |
| } |
| else |
| { |
| state.ensureTablePermission(table, Permission.SELECT); |
| } |
| |
| for (Function function : getFunctions()) |
| state.ensurePermission(Permission.EXECUTE, function); |
| } |
| |
| public void validate(ClientState state) throws InvalidRequestException |
| { |
| // Nothing to do, all validation has been done by RawStatement.prepare() |
| } |
| |
| public ResultMessage.Rows execute(QueryState state, QueryOptions options, long queryStartNanoTime) |
| { |
| ConsistencyLevel cl = options.getConsistency(); |
| checkNotNull(cl, "Invalid empty consistency level"); |
| |
| cl.validateForRead(); |
| |
| int nowInSec = options.getNowInSeconds(state); |
| int userLimit = getLimit(options); |
| int userPerPartitionLimit = getPerPartitionLimit(options); |
| int pageSize = options.getPageSize(); |
| |
| Selectors selectors = selection.newSelectors(options); |
| ReadQuery query = getQuery(options, selectors.getColumnFilter(), nowInSec, userLimit, userPerPartitionLimit, pageSize); |
| |
| if (aggregationSpec == null && (pageSize <= 0 || (query.limits().count() <= pageSize))) |
| return execute(query, options, state, selectors, nowInSec, userLimit, queryStartNanoTime); |
| |
| QueryPager pager = getPager(query, options); |
| |
| return execute(Pager.forDistributedQuery(pager, cl, state.getClientState()), |
| options, |
| selectors, |
| pageSize, |
| nowInSec, |
| userLimit, |
| queryStartNanoTime); |
| } |
| |
| public ReadQuery getQuery(QueryOptions options, int nowInSec) throws RequestValidationException |
| { |
| Selectors selectors = selection.newSelectors(options); |
| return getQuery(options, |
| selectors.getColumnFilter(), |
| nowInSec, |
| getLimit(options), |
| getPerPartitionLimit(options), |
| options.getPageSize()); |
| } |
| |
| public ReadQuery getQuery(QueryOptions options, |
| ColumnFilter columnFilter, |
| int nowInSec, |
| int userLimit, |
| int perPartitionLimit, |
| int pageSize) |
| { |
| boolean isPartitionRangeQuery = restrictions.isKeyRange() || restrictions.usesSecondaryIndexing(); |
| |
| DataLimits limit = getDataLimits(userLimit, perPartitionLimit, pageSize); |
| |
| if (isPartitionRangeQuery) |
| return getRangeCommand(options, columnFilter, limit, nowInSec); |
| |
| return getSliceCommands(options, columnFilter, limit, nowInSec); |
| } |
| |
| private ResultMessage.Rows execute(ReadQuery query, |
| QueryOptions options, |
| QueryState state, |
| Selectors selectors, |
| int nowInSec, |
| int userLimit, long queryStartNanoTime) throws RequestValidationException, RequestExecutionException |
| { |
| try (PartitionIterator data = query.execute(options.getConsistency(), state.getClientState(), queryStartNanoTime)) |
| { |
| return processResults(data, options, selectors, nowInSec, userLimit); |
| } |
| } |
| |
| @Override |
| public AuditLogContext getAuditLogContext() |
| { |
| return new AuditLogContext(AuditLogEntryType.SELECT, keyspace(), table.name); |
| } |
| |
| // Simple wrapper class to avoid some code duplication |
| private static abstract class Pager |
| { |
| protected QueryPager pager; |
| |
| protected Pager(QueryPager pager) |
| { |
| this.pager = pager; |
| } |
| |
| public static Pager forInternalQuery(QueryPager pager, ReadExecutionController executionController) |
| { |
| return new InternalPager(pager, executionController); |
| } |
| |
| public static Pager forDistributedQuery(QueryPager pager, ConsistencyLevel consistency, ClientState clientState) |
| { |
| return new NormalPager(pager, consistency, clientState); |
| } |
| |
| public boolean isExhausted() |
| { |
| return pager.isExhausted(); |
| } |
| |
| public PagingState state() |
| { |
| return pager.state(); |
| } |
| |
| public abstract PartitionIterator fetchPage(int pageSize, long queryStartNanoTime); |
| |
| public static class NormalPager extends Pager |
| { |
| private final ConsistencyLevel consistency; |
| private final ClientState clientState; |
| |
| private NormalPager(QueryPager pager, ConsistencyLevel consistency, ClientState clientState) |
| { |
| super(pager); |
| this.consistency = consistency; |
| this.clientState = clientState; |
| } |
| |
| public PartitionIterator fetchPage(int pageSize, long queryStartNanoTime) |
| { |
| return pager.fetchPage(pageSize, consistency, clientState, queryStartNanoTime); |
| } |
| } |
| |
| public static class InternalPager extends Pager |
| { |
| private final ReadExecutionController executionController; |
| |
| private InternalPager(QueryPager pager, ReadExecutionController executionController) |
| { |
| super(pager); |
| this.executionController = executionController; |
| } |
| |
| public PartitionIterator fetchPage(int pageSize, long queryStartNanoTime) |
| { |
| return pager.fetchPageInternal(pageSize, executionController); |
| } |
| } |
| } |
| |
| private ResultMessage.Rows execute(Pager pager, |
| QueryOptions options, |
| Selectors selectors, |
| int pageSize, |
| int nowInSec, |
| int userLimit, |
| long queryStartNanoTime) throws RequestValidationException, RequestExecutionException |
| { |
| if (aggregationSpec != null) |
| { |
| if (!restrictions.hasPartitionKeyRestrictions()) |
| { |
| warn("Aggregation query used without partition key"); |
| noSpamLogger.warn(String.format("Aggregation query used without partition key on table %s.%s, aggregation type: %s", |
| keyspace(), columnFamily(), aggregationSpec.kind())); |
| } |
| else if (restrictions.keyIsInRelation()) |
| { |
| warn("Aggregation query used on multiple partition keys (IN restriction)"); |
| noSpamLogger.warn(String.format("Aggregation query used on multiple partition keys (IN restriction) on table %s.%s, aggregation type: %s", |
| keyspace(), columnFamily(), aggregationSpec.kind())); |
| } |
| } |
| |
| // We can't properly do post-query ordering if we page (see #6722) |
| // For GROUP BY or aggregation queries we always page internally even if the user has turned paging off |
| checkFalse(pageSize > 0 && needsPostQueryOrdering(), |
| "Cannot page queries with both ORDER BY and a IN restriction on the partition key;" |
| + " you must either remove the ORDER BY or the IN and sort client side, or disable paging for this query"); |
| |
| ResultMessage.Rows msg; |
| try (PartitionIterator page = pager.fetchPage(pageSize, queryStartNanoTime)) |
| { |
| msg = processResults(page, options, selectors, nowInSec, userLimit); |
| } |
| |
| // Please note that the isExhausted state of the pager only gets updated when we've closed the page, so this |
| // shouldn't be moved inside the 'try' above. |
| if (!pager.isExhausted()) |
| msg.result.metadata.setHasMorePages(pager.state()); |
| |
| return msg; |
| } |
| |
| private void warn(String msg) |
| { |
| logger.warn(msg); |
| ClientWarn.instance.warn(msg); |
| } |
| |
| private ResultMessage.Rows processResults(PartitionIterator partitions, |
| QueryOptions options, |
| Selectors selectors, |
| int nowInSec, |
| int userLimit) throws RequestValidationException |
| { |
| ResultSet rset = process(partitions, options, selectors, nowInSec, userLimit); |
| return new ResultMessage.Rows(rset); |
| } |
| |
| public ResultMessage.Rows executeLocally(QueryState state, QueryOptions options) throws RequestExecutionException, RequestValidationException |
| { |
| return executeInternal(state, options, options.getNowInSeconds(state), System.nanoTime()); |
| } |
| |
| public ResultMessage.Rows executeInternal(QueryState state, QueryOptions options, int nowInSec, long queryStartNanoTime) throws RequestExecutionException, RequestValidationException |
| { |
| int userLimit = getLimit(options); |
| int userPerPartitionLimit = getPerPartitionLimit(options); |
| int pageSize = options.getPageSize(); |
| |
| Selectors selectors = selection.newSelectors(options); |
| ReadQuery query = getQuery(options, selectors.getColumnFilter(), nowInSec, userLimit, userPerPartitionLimit, pageSize); |
| |
| try (ReadExecutionController executionController = query.executionController()) |
| { |
| if (aggregationSpec == null && (pageSize <= 0 || (query.limits().count() <= pageSize))) |
| { |
| try (PartitionIterator data = query.executeInternal(executionController)) |
| { |
| return processResults(data, options, selectors, nowInSec, userLimit); |
| } |
| } |
| |
| QueryPager pager = getPager(query, options); |
| |
| return execute(Pager.forInternalQuery(pager, executionController), |
| options, |
| selectors, |
| pageSize, |
| nowInSec, |
| userLimit, |
| queryStartNanoTime); |
| } |
| } |
| |
| private QueryPager getPager(ReadQuery query, QueryOptions options) |
| { |
| QueryPager pager = query.getPager(options.getPagingState(), options.getProtocolVersion()); |
| |
| if (aggregationSpec == null || query.isEmpty()) |
| return pager; |
| |
| return new AggregationQueryPager(pager, query.limits()); |
| } |
| |
| public ResultSet process(PartitionIterator partitions, int nowInSec) throws InvalidRequestException |
| { |
| QueryOptions options = QueryOptions.DEFAULT; |
| Selectors selectors = selection.newSelectors(options); |
| return process(partitions, options, selectors, nowInSec, getLimit(options)); |
| } |
| |
| @Override |
| public String keyspace() |
| { |
| return table.keyspace; |
| } |
| |
| public String columnFamily() |
| { |
| return table.name; |
| } |
| |
| /** |
| * May be used by custom QueryHandler implementations |
| */ |
| public Selection getSelection() |
| { |
| return selection; |
| } |
| |
| /** |
| * May be used by custom QueryHandler implementations |
| */ |
| public StatementRestrictions getRestrictions() |
| { |
| return restrictions; |
| } |
| |
| private ReadQuery getSliceCommands(QueryOptions options, ColumnFilter columnFilter, DataLimits limit, int nowInSec) |
| { |
| Collection<ByteBuffer> keys = restrictions.getPartitionKeys(options); |
| if (keys.isEmpty()) |
| return ReadQuery.empty(table); |
| |
| ClusteringIndexFilter filter = makeClusteringIndexFilter(options, columnFilter); |
| if (filter == null || filter.isEmpty(table.comparator)) |
| return ReadQuery.empty(table); |
| |
| RowFilter rowFilter = getRowFilter(options); |
| |
| List<DecoratedKey> decoratedKeys = new ArrayList<>(keys.size()); |
| for (ByteBuffer key : keys) |
| { |
| QueryProcessor.validateKey(key); |
| decoratedKeys.add(table.partitioner.decorateKey(ByteBufferUtil.clone(key))); |
| } |
| |
| return SinglePartitionReadQuery.createGroup(table, nowInSec, columnFilter, rowFilter, limit, decoratedKeys, filter); |
| } |
| |
| /** |
| * Returns the slices fetched by this SELECT, assuming an internal call (no bound values in particular). |
| * <p> |
| * Note that if the SELECT intrinsically selects rows by names, we convert them into equivalent slices for |
| * the purpose of this method. This is used for MVs to restrict what needs to be read when we want to read |
| * everything that could be affected by a given view (and so, if the view SELECT statement has restrictions |
| * on the clustering columns, we can restrict what we read). |
| */ |
| public Slices clusteringIndexFilterAsSlices() |
| { |
| QueryOptions options = QueryOptions.forInternalCalls(Collections.emptyList()); |
| ColumnFilter columnFilter = selection.newSelectors(options).getColumnFilter(); |
| ClusteringIndexFilter filter = makeClusteringIndexFilter(options, columnFilter); |
| if (filter instanceof ClusteringIndexSliceFilter) |
| return ((ClusteringIndexSliceFilter)filter).requestedSlices(); |
| |
| Slices.Builder builder = new Slices.Builder(table.comparator); |
| for (Clustering<?> clustering: ((ClusteringIndexNamesFilter)filter).requestedRows()) |
| builder.add(Slice.make(clustering)); |
| return builder.build(); |
| } |
| |
| /** |
| * Returns a read command that can be used internally to query all the rows queried by this SELECT for a |
| * give key (used for materialized views). |
| */ |
| public SinglePartitionReadCommand internalReadForView(DecoratedKey key, int nowInSec) |
| { |
| QueryOptions options = QueryOptions.forInternalCalls(Collections.emptyList()); |
| ColumnFilter columnFilter = selection.newSelectors(options).getColumnFilter(); |
| ClusteringIndexFilter filter = makeClusteringIndexFilter(options, columnFilter); |
| RowFilter rowFilter = getRowFilter(options); |
| return SinglePartitionReadCommand.create(table, nowInSec, columnFilter, rowFilter, DataLimits.NONE, key, filter); |
| } |
| |
| /** |
| * The {@code RowFilter} for this SELECT, assuming an internal call (no bound values in particular). |
| */ |
| public RowFilter rowFilterForInternalCalls() |
| { |
| return getRowFilter(QueryOptions.forInternalCalls(Collections.emptyList())); |
| } |
| |
| private ReadQuery getRangeCommand(QueryOptions options, ColumnFilter columnFilter, DataLimits limit, int nowInSec) |
| { |
| ClusteringIndexFilter clusteringIndexFilter = makeClusteringIndexFilter(options, columnFilter); |
| if (clusteringIndexFilter == null) |
| return ReadQuery.empty(table); |
| |
| RowFilter rowFilter = getRowFilter(options); |
| |
| // The LIMIT provided by the user is the number of CQL row he wants returned. |
| // We want to have getRangeSlice to count the number of columns, not the number of keys. |
| AbstractBounds<PartitionPosition> keyBounds = restrictions.getPartitionKeyBounds(options); |
| if (keyBounds == null) |
| return ReadQuery.empty(table); |
| |
| ReadQuery command = |
| PartitionRangeReadQuery.create(table, nowInSec, columnFilter, rowFilter, limit, new DataRange(keyBounds, clusteringIndexFilter)); |
| |
| // If there's a secondary index that the command can use, have it validate the request parameters. |
| command.maybeValidateIndex(); |
| |
| return command; |
| } |
| |
| private ClusteringIndexFilter makeClusteringIndexFilter(QueryOptions options, ColumnFilter columnFilter) |
| { |
| if (parameters.isDistinct) |
| { |
| // We need to be able to distinguish between partition having live rows and those that don't. But |
| // doing so is not trivial since "having a live row" depends potentially on |
| // 1) when the query is performed, due to TTLs |
| // 2) how thing reconcile together between different nodes |
| // so that it's hard to really optimize properly internally. So to keep it simple, we simply query |
| // for the first row of the partition and hence uses Slices.ALL. We'll limit it to the first live |
| // row however in getLimit(). |
| return new ClusteringIndexSliceFilter(Slices.ALL, false); |
| } |
| |
| if (restrictions.isColumnRange()) |
| { |
| Slices slices = makeSlices(options); |
| if (slices == Slices.NONE && !selection.containsStaticColumns()) |
| return null; |
| |
| return new ClusteringIndexSliceFilter(slices, isReversed); |
| } |
| |
| NavigableSet<Clustering<?>> clusterings = getRequestedRows(options); |
| // We can have no clusterings if either we're only selecting the static columns, or if we have |
| // a 'IN ()' for clusterings. In that case, we still want to query if some static columns are |
| // queried. But we're fine otherwise. |
| if (clusterings.isEmpty() && columnFilter.fetchedColumns().statics.isEmpty()) |
| return null; |
| |
| return new ClusteringIndexNamesFilter(clusterings, isReversed); |
| } |
| |
| @VisibleForTesting |
| public Slices makeSlices(QueryOptions options) |
| throws InvalidRequestException |
| { |
| SortedSet<ClusteringBound<?>> startBounds = restrictions.getClusteringColumnsBounds(Bound.START, options); |
| SortedSet<ClusteringBound<?>> endBounds = restrictions.getClusteringColumnsBounds(Bound.END, options); |
| assert startBounds.size() == endBounds.size(); |
| |
| // The case where startBounds == 1 is common enough that it's worth optimizing |
| if (startBounds.size() == 1) |
| { |
| ClusteringBound<?> start = startBounds.first(); |
| ClusteringBound<?> end = endBounds.first(); |
| return Slice.isEmpty(table.comparator, start, end) |
| ? Slices.NONE |
| : Slices.with(table.comparator, Slice.make(start, end)); |
| } |
| |
| Slices.Builder builder = new Slices.Builder(table.comparator, startBounds.size()); |
| Iterator<ClusteringBound<?>> startIter = startBounds.iterator(); |
| Iterator<ClusteringBound<?>> endIter = endBounds.iterator(); |
| while (startIter.hasNext() && endIter.hasNext()) |
| { |
| ClusteringBound<?> start = startIter.next(); |
| ClusteringBound<?> end = endIter.next(); |
| |
| // Ignore slices that are nonsensical |
| if (Slice.isEmpty(table.comparator, start, end)) |
| continue; |
| |
| builder.add(start, end); |
| } |
| |
| return builder.build(); |
| } |
| |
| private DataLimits getDataLimits(int userLimit, int perPartitionLimit, int pageSize) |
| { |
| int cqlRowLimit = DataLimits.NO_LIMIT; |
| int cqlPerPartitionLimit = DataLimits.NO_LIMIT; |
| |
| // If we do post ordering we need to get all the results sorted before we can trim them. |
| if (aggregationSpec != AggregationSpecification.AGGREGATE_EVERYTHING) |
| { |
| if (!needsPostQueryOrdering()) |
| cqlRowLimit = userLimit; |
| cqlPerPartitionLimit = perPartitionLimit; |
| } |
| |
| // Group by and aggregation queries will always be paged internally to avoid OOM. |
| // If the user provided a pageSize we'll use that to page internally (because why not), otherwise we use our default |
| if (pageSize <= 0) |
| pageSize = DEFAULT_PAGE_SIZE; |
| |
| // Aggregation queries work fine on top of the group by paging but to maintain |
| // backward compatibility we need to use the old way. |
| if (aggregationSpec != null && aggregationSpec != AggregationSpecification.AGGREGATE_EVERYTHING) |
| { |
| if (parameters.isDistinct) |
| return DataLimits.distinctLimits(cqlRowLimit); |
| |
| return DataLimits.groupByLimits(cqlRowLimit, |
| cqlPerPartitionLimit, |
| pageSize, |
| aggregationSpec); |
| } |
| |
| if (parameters.isDistinct) |
| return cqlRowLimit == DataLimits.NO_LIMIT ? DataLimits.DISTINCT_NONE : DataLimits.distinctLimits(cqlRowLimit); |
| |
| return DataLimits.cqlLimits(cqlRowLimit, cqlPerPartitionLimit); |
| } |
| |
| /** |
| * Returns the limit specified by the user. |
| * May be used by custom QueryHandler implementations |
| * |
| * @return the limit specified by the user or <code>DataLimits.NO_LIMIT</code> if no value |
| * as been specified. |
| */ |
| public int getLimit(QueryOptions options) |
| { |
| return getLimit(limit, options); |
| } |
| |
| /** |
| * Returns the per partition limit specified by the user. |
| * May be used by custom QueryHandler implementations |
| * |
| * @return the per partition limit specified by the user or <code>DataLimits.NO_LIMIT</code> if no value |
| * as been specified. |
| */ |
| public int getPerPartitionLimit(QueryOptions options) |
| { |
| return getLimit(perPartitionLimit, options); |
| } |
| |
| private int getLimit(Term limit, QueryOptions options) |
| { |
| int userLimit = DataLimits.NO_LIMIT; |
| |
| if (limit != null) |
| { |
| ByteBuffer b = checkNotNull(limit.bindAndGet(options), "Invalid null value of limit"); |
| // treat UNSET limit value as 'unlimited' |
| if (b != UNSET_BYTE_BUFFER) |
| { |
| try |
| { |
| Int32Type.instance.validate(b); |
| userLimit = Int32Type.instance.compose(b); |
| checkTrue(userLimit > 0, "LIMIT must be strictly positive"); |
| } |
| catch (MarshalException e) |
| { |
| throw new InvalidRequestException("Invalid limit value"); |
| } |
| } |
| } |
| return userLimit; |
| } |
| |
| private NavigableSet<Clustering<?>> getRequestedRows(QueryOptions options) throws InvalidRequestException |
| { |
| // Note: getRequestedColumns don't handle static columns, but due to CASSANDRA-5762 |
| // we always do a slice for CQL3 tables, so it's ok to ignore them here |
| assert !restrictions.isColumnRange(); |
| return restrictions.getClusteringColumns(options); |
| } |
| |
| /** |
| * May be used by custom QueryHandler implementations |
| */ |
| public RowFilter getRowFilter(QueryOptions options) throws InvalidRequestException |
| { |
| IndexRegistry indexRegistry = IndexRegistry.obtain(table); |
| return restrictions.getRowFilter(indexRegistry, options); |
| } |
| |
| private ResultSet process(PartitionIterator partitions, |
| QueryOptions options, |
| Selectors selectors, |
| int nowInSec, |
| int userLimit) throws InvalidRequestException |
| { |
| GroupMaker groupMaker = aggregationSpec == null ? null : aggregationSpec.newGroupMaker(); |
| ResultSetBuilder result = new ResultSetBuilder(getResultMetadata(), selectors, groupMaker); |
| |
| while (partitions.hasNext()) |
| { |
| try (RowIterator partition = partitions.next()) |
| { |
| processPartition(partition, options, result, nowInSec); |
| } |
| } |
| |
| ResultSet cqlRows = result.build(); |
| |
| orderResults(cqlRows); |
| |
| cqlRows.trim(userLimit); |
| |
| return cqlRows; |
| } |
| |
| public static ByteBuffer[] getComponents(TableMetadata metadata, DecoratedKey dk) |
| { |
| ByteBuffer key = dk.getKey(); |
| if (metadata.partitionKeyType instanceof CompositeType) |
| { |
| return ((CompositeType)metadata.partitionKeyType).split(key); |
| } |
| else |
| { |
| return new ByteBuffer[]{ key }; |
| } |
| } |
| |
| // Used by ModificationStatement for CAS operations |
| void processPartition(RowIterator partition, QueryOptions options, ResultSetBuilder result, int nowInSec) |
| throws InvalidRequestException |
| { |
| ProtocolVersion protocolVersion = options.getProtocolVersion(); |
| |
| ByteBuffer[] keyComponents = getComponents(table, partition.partitionKey()); |
| |
| Row staticRow = partition.staticRow(); |
| // If there is no rows, we include the static content if we should and we're done. |
| if (!partition.hasNext()) |
| { |
| if (!staticRow.isEmpty() && restrictions.returnStaticContentOnPartitionWithNoRows()) |
| { |
| result.newRow(partition.partitionKey(), staticRow.clustering()); |
| for (ColumnMetadata def : selection.getColumns()) |
| { |
| switch (def.kind) |
| { |
| case PARTITION_KEY: |
| result.add(keyComponents[def.position()]); |
| break; |
| case STATIC: |
| addValue(result, def, staticRow, nowInSec, protocolVersion); |
| break; |
| default: |
| result.add((ByteBuffer)null); |
| } |
| } |
| } |
| return; |
| } |
| |
| while (partition.hasNext()) |
| { |
| Row row = partition.next(); |
| result.newRow( partition.partitionKey(), row.clustering()); |
| // Respect selection order |
| for (ColumnMetadata def : selection.getColumns()) |
| { |
| switch (def.kind) |
| { |
| case PARTITION_KEY: |
| result.add(keyComponents[def.position()]); |
| break; |
| case CLUSTERING: |
| result.add(row.clustering().bufferAt(def.position())); |
| break; |
| case REGULAR: |
| addValue(result, def, row, nowInSec, protocolVersion); |
| break; |
| case STATIC: |
| addValue(result, def, staticRow, nowInSec, protocolVersion); |
| break; |
| } |
| } |
| } |
| } |
| |
| private static void addValue(ResultSetBuilder result, ColumnMetadata def, Row row, int nowInSec, ProtocolVersion protocolVersion) |
| { |
| if (def.isComplex()) |
| { |
| assert def.type.isMultiCell(); |
| ComplexColumnData complexData = row.getComplexColumnData(def); |
| if (complexData == null) |
| result.add(null); |
| else if (def.type.isCollection()) |
| result.add(((CollectionType) def.type).serializeForNativeProtocol(complexData.iterator(), protocolVersion)); |
| else |
| result.add(((UserType) def.type).serializeForNativeProtocol(complexData.iterator(), protocolVersion)); |
| } |
| else |
| { |
| result.add(row.getCell(def), nowInSec); |
| } |
| } |
| |
| private boolean needsPostQueryOrdering() |
| { |
| // We need post-query ordering only for queries with IN on the partition key and an ORDER BY. |
| return restrictions.keyIsInRelation() && !parameters.orderings.isEmpty(); |
| } |
| |
| /** |
| * Orders results when multiple keys are selected (using IN) |
| */ |
| private void orderResults(ResultSet cqlRows) |
| { |
| if (cqlRows.size() == 0 || !needsPostQueryOrdering()) |
| return; |
| |
| Collections.sort(cqlRows.rows, orderingComparator); |
| } |
| |
| public static class RawStatement extends QualifiedStatement |
| { |
| public final Parameters parameters; |
| public final List<RawSelector> selectClause; |
| public final WhereClause whereClause; |
| public final Term.Raw limit; |
| public final Term.Raw perPartitionLimit; |
| |
| public RawStatement(QualifiedName cfName, |
| Parameters parameters, |
| List<RawSelector> selectClause, |
| WhereClause whereClause, |
| Term.Raw limit, |
| Term.Raw perPartitionLimit) |
| { |
| super(cfName); |
| this.parameters = parameters; |
| this.selectClause = selectClause; |
| this.whereClause = whereClause; |
| this.limit = limit; |
| this.perPartitionLimit = perPartitionLimit; |
| } |
| |
| public SelectStatement prepare(ClientState state) |
| { |
| return prepare(false); |
| } |
| |
| public SelectStatement prepare(boolean forView) throws InvalidRequestException |
| { |
| TableMetadata table = Schema.instance.validateTable(keyspace(), name()); |
| |
| List<Selectable> selectables = RawSelector.toSelectables(selectClause, table); |
| boolean containsOnlyStaticColumns = selectOnlyStaticColumns(table, selectables); |
| |
| StatementRestrictions restrictions = prepareRestrictions(table, bindVariables, containsOnlyStaticColumns, forView); |
| |
| // If we order post-query, the sorted column needs to be in the ResultSet for sorting, |
| // even if we don't ultimately ship them to the client (CASSANDRA-4911). |
| Map<ColumnMetadata, Boolean> orderingColumns = getOrderingColumns(table); |
| Set<ColumnMetadata> resultSetOrderingColumns = restrictions.keyIsInRelation() ? orderingColumns.keySet() |
| : Collections.emptySet(); |
| |
| Selection selection = prepareSelection(table, |
| selectables, |
| bindVariables, |
| resultSetOrderingColumns, |
| restrictions); |
| |
| if (parameters.isDistinct) |
| { |
| checkNull(perPartitionLimit, "PER PARTITION LIMIT is not allowed with SELECT DISTINCT queries"); |
| validateDistinctSelection(table, selection, restrictions); |
| } |
| |
| AggregationSpecification aggregationSpec = getAggregationSpecification(table, |
| selection, |
| restrictions, |
| parameters.isDistinct); |
| |
| checkFalse(aggregationSpec == AggregationSpecification.AGGREGATE_EVERYTHING && perPartitionLimit != null, |
| "PER PARTITION LIMIT is not allowed with aggregate queries."); |
| |
| Comparator<List<ByteBuffer>> orderingComparator = null; |
| boolean isReversed = false; |
| |
| if (!orderingColumns.isEmpty()) |
| { |
| assert !forView; |
| verifyOrderingIsAllowed(restrictions); |
| orderingComparator = getOrderingComparator(selection, restrictions, orderingColumns); |
| isReversed = isReversed(table, orderingColumns, restrictions); |
| if (isReversed) |
| orderingComparator = Collections.reverseOrder(orderingComparator); |
| } |
| |
| checkNeedsFiltering(restrictions); |
| |
| return new SelectStatement(table, |
| bindVariables, |
| parameters, |
| selection, |
| restrictions, |
| isReversed, |
| aggregationSpec, |
| orderingComparator, |
| prepareLimit(bindVariables, limit, keyspace(), limitReceiver()), |
| prepareLimit(bindVariables, perPartitionLimit, keyspace(), perPartitionLimitReceiver())); |
| } |
| |
| private Selection prepareSelection(TableMetadata table, |
| List<Selectable> selectables, |
| VariableSpecifications boundNames, |
| Set<ColumnMetadata> resultSetOrderingColumns, |
| StatementRestrictions restrictions) |
| { |
| boolean hasGroupBy = !parameters.groups.isEmpty(); |
| |
| if (selectables.isEmpty()) // wildcard query |
| { |
| return hasGroupBy ? Selection.wildcardWithGroupBy(table, boundNames, parameters.isJson, restrictions.returnStaticContentOnPartitionWithNoRows()) |
| : Selection.wildcard(table, parameters.isJson, restrictions.returnStaticContentOnPartitionWithNoRows()); |
| } |
| |
| return Selection.fromSelectors(table, |
| selectables, |
| boundNames, |
| resultSetOrderingColumns, |
| restrictions.nonPKRestrictedColumns(false), |
| hasGroupBy, |
| parameters.isJson, |
| restrictions.returnStaticContentOnPartitionWithNoRows()); |
| } |
| |
| /** |
| * Checks if the specified selectables select only partition key columns or static columns |
| * |
| * @param table the table metadata |
| * @param selectables the selectables to check |
| * @return {@code true} if the specified selectables select only partition key columns or static columns, |
| * {@code false} otherwise. |
| */ |
| private boolean selectOnlyStaticColumns(TableMetadata table, List<Selectable> selectables) |
| { |
| if (table.isStaticCompactTable()) |
| return false; |
| |
| if (!table.hasStaticColumns() || selectables.isEmpty()) |
| return false; |
| |
| return Selectable.selectColumns(selectables, (column) -> column.isStatic()) |
| && !Selectable.selectColumns(selectables, (column) -> !column.isPartitionKey() && !column.isStatic()); |
| } |
| |
| /** |
| * Returns the columns used to order the data. |
| * @return the columns used to order the data. |
| */ |
| private Map<ColumnMetadata, Boolean> getOrderingColumns(TableMetadata table) |
| { |
| if (parameters.orderings.isEmpty()) |
| return Collections.emptyMap(); |
| |
| Map<ColumnMetadata, Boolean> orderingColumns = new LinkedHashMap<>(); |
| for (Map.Entry<ColumnIdentifier, Boolean> entry : parameters.orderings.entrySet()) |
| { |
| orderingColumns.put(table.getExistingColumn(entry.getKey()), entry.getValue()); |
| } |
| return orderingColumns; |
| } |
| |
| /** |
| * Prepares the restrictions. |
| * |
| * @param metadata the column family meta data |
| * @param boundNames the variable specifications |
| * @param selectsOnlyStaticColumns {@code true} if the query select only static columns, {@code false} otherwise. |
| * @return the restrictions |
| * @throws InvalidRequestException if a problem occurs while building the restrictions |
| */ |
| private StatementRestrictions prepareRestrictions(TableMetadata metadata, |
| VariableSpecifications boundNames, |
| boolean selectsOnlyStaticColumns, |
| boolean forView) throws InvalidRequestException |
| { |
| return new StatementRestrictions(StatementType.SELECT, |
| metadata, |
| whereClause, |
| boundNames, |
| selectsOnlyStaticColumns, |
| parameters.allowFiltering, |
| forView); |
| } |
| |
| /** Returns a Term for the limit or null if no limit is set */ |
| private Term prepareLimit(VariableSpecifications boundNames, Term.Raw limit, |
| String keyspace, ColumnSpecification limitReceiver) throws InvalidRequestException |
| { |
| if (limit == null) |
| return null; |
| |
| Term prepLimit = limit.prepare(keyspace, limitReceiver); |
| prepLimit.collectMarkerSpecification(boundNames); |
| return prepLimit; |
| } |
| |
| private static void verifyOrderingIsAllowed(StatementRestrictions restrictions) throws InvalidRequestException |
| { |
| checkFalse(restrictions.usesSecondaryIndexing(), "ORDER BY with 2ndary indexes is not supported."); |
| checkFalse(restrictions.isKeyRange(), "ORDER BY is only supported when the partition key is restricted by an EQ or an IN."); |
| } |
| |
| private static void validateDistinctSelection(TableMetadata metadata, |
| Selection selection, |
| StatementRestrictions restrictions) |
| throws InvalidRequestException |
| { |
| checkFalse(restrictions.hasClusteringColumnsRestrictions() || |
| (restrictions.hasNonPrimaryKeyRestrictions() && !restrictions.nonPKRestrictedColumns(true).stream().allMatch(ColumnMetadata::isStatic)), |
| "SELECT DISTINCT with WHERE clause only supports restriction by partition key and/or static columns."); |
| |
| Collection<ColumnMetadata> requestedColumns = selection.getColumns(); |
| for (ColumnMetadata def : requestedColumns) |
| checkFalse(!def.isPartitionKey() && !def.isStatic(), |
| "SELECT DISTINCT queries must only request partition key columns and/or static columns (not %s)", |
| def.name); |
| |
| // If it's a key range, we require that all partition key columns are selected so we don't have to bother |
| // with post-query grouping. |
| if (!restrictions.isKeyRange()) |
| return; |
| |
| for (ColumnMetadata def : metadata.partitionKeyColumns()) |
| checkTrue(requestedColumns.contains(def), |
| "SELECT DISTINCT queries must request all the partition key columns (missing %s)", def.name); |
| } |
| |
| /** |
| * Creates the <code>AggregationSpecification</code>s used to make the aggregates. |
| * |
| * @param metadata the table metadata |
| * @param selection the selection |
| * @param restrictions the restrictions |
| * @param isDistinct <code>true</code> if the query is a DISTINCT one. |
| * @return the <code>AggregationSpecification</code>s used to make the aggregates |
| */ |
| private AggregationSpecification getAggregationSpecification(TableMetadata metadata, |
| Selection selection, |
| StatementRestrictions restrictions, |
| boolean isDistinct) |
| { |
| if (parameters.groups.isEmpty()) |
| return selection.isAggregate() ? AggregationSpecification.AGGREGATE_EVERYTHING |
| : null; |
| |
| int clusteringPrefixSize = 0; |
| |
| Iterator<ColumnMetadata> pkColumns = metadata.primaryKeyColumns().iterator(); |
| for (ColumnIdentifier id : parameters.groups) |
| { |
| ColumnMetadata def = metadata.getExistingColumn(id); |
| |
| checkTrue(def.isPartitionKey() || def.isClusteringColumn(), |
| "Group by is currently only supported on the columns of the PRIMARY KEY, got %s", def.name); |
| |
| while (true) |
| { |
| checkTrue(pkColumns.hasNext(), |
| "Group by currently only support groups of columns following their declared order in the PRIMARY KEY"); |
| |
| ColumnMetadata pkColumn = pkColumns.next(); |
| |
| if (pkColumn.isClusteringColumn()) |
| clusteringPrefixSize++; |
| |
| // As we do not support grouping on only part of the partition key, we only need to know |
| // which clustering columns need to be used to build the groups |
| if (pkColumn.equals(def)) |
| break; |
| |
| checkTrue(restrictions.isColumnRestrictedByEq(pkColumn), |
| "Group by currently only support groups of columns following their declared order in the PRIMARY KEY"); |
| } |
| } |
| |
| checkFalse(pkColumns.hasNext() && pkColumns.next().isPartitionKey(), |
| "Group by is not supported on only a part of the partition key"); |
| |
| checkFalse(clusteringPrefixSize > 0 && isDistinct, |
| "Grouping on clustering columns is not allowed for SELECT DISTINCT queries"); |
| |
| return AggregationSpecification.aggregatePkPrefix(metadata.comparator, clusteringPrefixSize); |
| } |
| |
| private Comparator<List<ByteBuffer>> getOrderingComparator(Selection selection, |
| StatementRestrictions restrictions, |
| Map<ColumnMetadata, Boolean> orderingColumns) |
| throws InvalidRequestException |
| { |
| if (!restrictions.keyIsInRelation()) |
| return null; |
| |
| List<Integer> idToSort = new ArrayList<Integer>(orderingColumns.size()); |
| List<Comparator<ByteBuffer>> sorters = new ArrayList<Comparator<ByteBuffer>>(orderingColumns.size()); |
| |
| for (ColumnMetadata orderingColumn : orderingColumns.keySet()) |
| { |
| idToSort.add(selection.getOrderingIndex(orderingColumn)); |
| sorters.add(orderingColumn.type); |
| } |
| return idToSort.size() == 1 ? new SingleColumnComparator(idToSort.get(0), sorters.get(0)) |
| : new CompositeComparator(sorters, idToSort); |
| } |
| |
| private boolean isReversed(TableMetadata table, Map<ColumnMetadata, Boolean> orderingColumns, StatementRestrictions restrictions) throws InvalidRequestException |
| { |
| Boolean[] reversedMap = new Boolean[table.clusteringColumns().size()]; |
| int i = 0; |
| for (Map.Entry<ColumnMetadata, Boolean> entry : orderingColumns.entrySet()) |
| { |
| ColumnMetadata def = entry.getKey(); |
| boolean reversed = entry.getValue(); |
| |
| checkTrue(def.isClusteringColumn(), |
| "Order by is currently only supported on the clustered columns of the PRIMARY KEY, got %s", def.name); |
| |
| while (i != def.position()) |
| { |
| checkTrue(restrictions.isColumnRestrictedByEq(table.clusteringColumns().get(i++)), |
| "Order by currently only supports the ordering of columns following their declared order in the PRIMARY KEY"); |
| } |
| i++; |
| reversedMap[def.position()] = (reversed != def.isReversedType()); |
| } |
| |
| // Check that all boolean in reversedMap, if set, agrees |
| Boolean isReversed = null; |
| for (Boolean b : reversedMap) |
| { |
| // Column on which order is specified can be in any order |
| if (b == null) |
| continue; |
| |
| if (isReversed == null) |
| { |
| isReversed = b; |
| continue; |
| } |
| checkTrue(isReversed.equals(b), "Unsupported order by relation"); |
| } |
| assert isReversed != null; |
| return isReversed; |
| } |
| |
| /** If ALLOW FILTERING was not specified, this verifies that it is not needed */ |
| private void checkNeedsFiltering(StatementRestrictions restrictions) throws InvalidRequestException |
| { |
| // non-key-range non-indexed queries cannot involve filtering underneath |
| if (!parameters.allowFiltering && (restrictions.isKeyRange() || restrictions.usesSecondaryIndexing())) |
| { |
| // We will potentially filter data if either: |
| // - Have more than one IndexExpression |
| // - Have no index expression and the row filter is not the identity |
| checkFalse(restrictions.needFiltering(), StatementRestrictions.REQUIRES_ALLOW_FILTERING_MESSAGE); |
| } |
| } |
| |
| private ColumnSpecification limitReceiver() |
| { |
| return new ColumnSpecification(keyspace(), name(), new ColumnIdentifier("[limit]", true), Int32Type.instance); |
| } |
| |
| private ColumnSpecification perPartitionLimitReceiver() |
| { |
| return new ColumnSpecification(keyspace(), name(), new ColumnIdentifier("[per_partition_limit]", true), Int32Type.instance); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return MoreObjects.toStringHelper(this) |
| .add("name", qualifiedName) |
| .add("selectClause", selectClause) |
| .add("whereClause", whereClause) |
| .add("isDistinct", parameters.isDistinct) |
| .toString(); |
| } |
| } |
| |
| public static class Parameters |
| { |
| // Public because CASSANDRA-9858 |
| public final Map<ColumnIdentifier, Boolean> orderings; |
| public final List<ColumnIdentifier> groups; |
| public final boolean isDistinct; |
| public final boolean allowFiltering; |
| public final boolean isJson; |
| |
| public Parameters(Map<ColumnIdentifier, Boolean> orderings, |
| List<ColumnIdentifier> groups, |
| boolean isDistinct, |
| boolean allowFiltering, |
| boolean isJson) |
| { |
| this.orderings = orderings; |
| this.groups = groups; |
| this.isDistinct = isDistinct; |
| this.allowFiltering = allowFiltering; |
| this.isJson = isJson; |
| } |
| } |
| |
| private static abstract class ColumnComparator<T> implements Comparator<T> |
| { |
| protected final int compare(Comparator<ByteBuffer> comparator, ByteBuffer aValue, ByteBuffer bValue) |
| { |
| if (aValue == null) |
| return bValue == null ? 0 : -1; |
| |
| return bValue == null ? 1 : comparator.compare(aValue, bValue); |
| } |
| } |
| |
| /** |
| * Used in orderResults(...) method when single 'ORDER BY' condition where given |
| */ |
| private static class SingleColumnComparator extends ColumnComparator<List<ByteBuffer>> |
| { |
| private final int index; |
| private final Comparator<ByteBuffer> comparator; |
| |
| public SingleColumnComparator(int columnIndex, Comparator<ByteBuffer> orderer) |
| { |
| index = columnIndex; |
| comparator = orderer; |
| } |
| |
| public int compare(List<ByteBuffer> a, List<ByteBuffer> b) |
| { |
| return compare(comparator, a.get(index), b.get(index)); |
| } |
| } |
| |
| /** |
| * Used in orderResults(...) method when multiple 'ORDER BY' conditions where given |
| */ |
| private static class CompositeComparator extends ColumnComparator<List<ByteBuffer>> |
| { |
| private final List<Comparator<ByteBuffer>> orderTypes; |
| private final List<Integer> positions; |
| |
| private CompositeComparator(List<Comparator<ByteBuffer>> orderTypes, List<Integer> positions) |
| { |
| this.orderTypes = orderTypes; |
| this.positions = positions; |
| } |
| |
| public int compare(List<ByteBuffer> a, List<ByteBuffer> b) |
| { |
| for (int i = 0; i < positions.size(); i++) |
| { |
| Comparator<ByteBuffer> type = orderTypes.get(i); |
| int columnPos = positions.get(i); |
| |
| int comparison = compare(type, a.get(columnPos), b.get(columnPos)); |
| |
| if (comparison != 0) |
| return comparison; |
| } |
| |
| return 0; |
| } |
| } |
| |
| @Override |
| public String toString() |
| { |
| return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE); |
| } |
| } |
