| /* |
| * 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.selection; |
| |
| import java.nio.ByteBuffer; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.apache.cassandra.cql3.ResultSet; |
| import org.apache.cassandra.cql3.ResultSet.ResultMetadata; |
| import org.apache.cassandra.cql3.selection.Selection.Selectors; |
| import org.apache.cassandra.db.Clustering; |
| import org.apache.cassandra.db.DecoratedKey; |
| import org.apache.cassandra.db.aggregation.GroupMaker; |
| import org.apache.cassandra.db.context.CounterContext; |
| import org.apache.cassandra.db.rows.Cell; |
| import org.apache.cassandra.utils.ByteBufferUtil; |
| |
| public final class ResultSetBuilder |
| { |
| private final ResultSet resultSet; |
| |
| /** |
| * As multiple thread can access a <code>Selection</code> instance each <code>ResultSetBuilder</code> will use |
| * its own <code>Selectors</code> instance. |
| */ |
| private final Selectors selectors; |
| |
| /** |
| * The <code>GroupMaker</code> used to build the aggregates. |
| */ |
| private final GroupMaker groupMaker; |
| |
| /* |
| * We'll build CQL3 row one by one. |
| * The currentRow is the values for the (CQL3) columns we've fetched. |
| * We also collect timestamps and ttls for the case where the writetime and |
| * ttl functions are used. Note that we might collect timestamp and/or ttls |
| * we don't care about, but since the array below are allocated just once, |
| * it doesn't matter performance wise. |
| */ |
| List<ByteBuffer> current; |
| final long[] timestamps; |
| final int[] ttls; |
| |
| public ResultSetBuilder(ResultMetadata metadata, Selectors selectors) |
| { |
| this(metadata, selectors, null); |
| } |
| |
| public ResultSetBuilder(ResultMetadata metadata, Selectors selectors, GroupMaker groupMaker) |
| { |
| this.resultSet = new ResultSet(metadata.copy(), new ArrayList<List<ByteBuffer>>()); |
| this.selectors = selectors; |
| this.groupMaker = groupMaker; |
| this.timestamps = selectors.collectTimestamps() ? new long[selectors.numberOfFetchedColumns()] : null; |
| this.ttls = selectors.collectTTLs() ? new int[selectors.numberOfFetchedColumns()] : null; |
| |
| // We use MIN_VALUE to indicate no timestamp and -1 for no ttl |
| if (timestamps != null) |
| Arrays.fill(timestamps, Long.MIN_VALUE); |
| if (ttls != null) |
| Arrays.fill(ttls, -1); |
| } |
| |
| public void add(ByteBuffer v) |
| { |
| current.add(v); |
| } |
| |
| public void add(Cell<?> c, int nowInSec) |
| { |
| if (c == null) |
| { |
| current.add(null); |
| return; |
| } |
| |
| current.add(value(c)); |
| |
| if (timestamps != null) |
| timestamps[current.size() - 1] = c.timestamp(); |
| |
| if (ttls != null) |
| ttls[current.size() - 1] = remainingTTL(c, nowInSec); |
| } |
| |
| private int remainingTTL(Cell<?> c, int nowInSec) |
| { |
| if (!c.isExpiring()) |
| return -1; |
| |
| int remaining = c.localDeletionTime() - nowInSec; |
| return remaining >= 0 ? remaining : -1; |
| } |
| |
| private <V> ByteBuffer value(Cell<V> c) |
| { |
| return c.isCounterCell() |
| ? ByteBufferUtil.bytes(CounterContext.instance().total(c.value(), c.accessor())) |
| : c.buffer(); |
| } |
| |
| /** |
| * Notifies this <code>Builder</code> that a new row is being processed. |
| * |
| * @param partitionKey the partition key of the new row |
| * @param clustering the clustering of the new row |
| */ |
| public void newRow(DecoratedKey partitionKey, Clustering<?> clustering) |
| { |
| // The groupMaker needs to be called for each row |
| boolean isNewAggregate = groupMaker == null || groupMaker.isNewGroup(partitionKey, clustering); |
| if (current != null) |
| { |
| selectors.addInputRow(this); |
| if (isNewAggregate) |
| { |
| resultSet.addRow(getOutputRow()); |
| selectors.reset(); |
| } |
| } |
| current = new ArrayList<>(selectors.numberOfFetchedColumns()); |
| |
| // Timestamps and TTLs are arrays per row, we must null them out between rows |
| if (timestamps != null) |
| Arrays.fill(timestamps, Long.MIN_VALUE); |
| if (ttls != null) |
| Arrays.fill(ttls, -1); |
| } |
| |
| /** |
| * Builds the <code>ResultSet</code> |
| */ |
| public ResultSet build() |
| { |
| if (current != null) |
| { |
| selectors.addInputRow(this); |
| resultSet.addRow(getOutputRow()); |
| selectors.reset(); |
| current = null; |
| } |
| |
| // For aggregates we need to return a row even it no records have been found |
| if (resultSet.isEmpty() && groupMaker != null && groupMaker.returnAtLeastOneRow()) |
| resultSet.addRow(getOutputRow()); |
| return resultSet; |
| } |
| |
| private List<ByteBuffer> getOutputRow() |
| { |
| return selectors.getOutputRow(); |
| } |
| } |