| /* |
| * 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.db.aggregation; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| import org.apache.cassandra.db.Clustering; |
| import org.apache.cassandra.db.ClusteringComparator; |
| import org.apache.cassandra.db.TypeSizes; |
| import org.apache.cassandra.db.marshal.ByteArrayAccessor; |
| import org.apache.cassandra.io.util.DataInputPlus; |
| import org.apache.cassandra.io.util.DataOutputPlus; |
| import org.apache.cassandra.utils.ByteBufferUtil; |
| |
| /** |
| * {@code GroupMaker} state. |
| * |
| * <p>The state contains the primary key of the last row that has been processed by the previous |
| * {@code GroupMaker} used. It can be passed to a {@code GroupMaker} to allow to resuming the grouping. |
| * </p> |
| * <p> |
| * {@code GroupingState} is only used for internal paging. When a new page is requested by a client the initial state |
| * will always be empty.</p> |
| * <p> |
| * If the state has a partition key but no clustering, it means that the previous group ended at the end of the |
| * previous partition. If the clustering is not null it means that we are in the middle of a group. |
| * </p> |
| */ |
| public final class GroupingState |
| { |
| public static final GroupingState.Serializer serializer = new Serializer(); |
| |
| public static final GroupingState EMPTY_STATE = new GroupingState(null, null); |
| |
| /** |
| * The last row partition key. |
| */ |
| private final ByteBuffer partitionKey; |
| |
| /** |
| * The last row clustering |
| */ |
| final Clustering<?> clustering; |
| |
| public GroupingState(ByteBuffer partitionKey, Clustering<?> clustering) |
| { |
| this.partitionKey = partitionKey; |
| this.clustering = clustering; |
| } |
| |
| /** |
| * Returns the last row partition key or <code>null</code> if no rows has been processed yet. |
| * @return the last row partition key or <code>null</code> if no rows has been processed yet |
| */ |
| public ByteBuffer partitionKey() |
| { |
| return partitionKey; |
| } |
| |
| /** |
| * Returns the last row clustering or <code>null</code> if either no rows has been processed yet or the last |
| * row was a static row. |
| * @return he last row clustering or <code>null</code> if either no rows has been processed yet or the last |
| * row was a static row |
| */ |
| public Clustering<?> clustering() |
| { |
| return clustering; |
| } |
| |
| /** |
| * Checks if the state contains a Clustering for the last row that has been processed. |
| * @return <code>true</code> if the state contains a Clustering for the last row that has been processed, |
| * <code>false</code> otherwise. |
| */ |
| public boolean hasClustering() |
| { |
| return clustering != null; |
| } |
| |
| public static class Serializer |
| { |
| public void serialize(GroupingState state, DataOutputPlus out, int version, ClusteringComparator comparator) throws IOException |
| { |
| boolean hasPartitionKey = state.partitionKey != null; |
| out.writeBoolean(hasPartitionKey); |
| if (hasPartitionKey) |
| { |
| ByteBufferUtil.writeWithVIntLength(state.partitionKey, out); |
| boolean hasClustering = state.hasClustering(); |
| out.writeBoolean(hasClustering); |
| if (hasClustering) |
| Clustering.serializer.serialize(state.clustering, out, version, comparator.subtypes()); |
| } |
| } |
| |
| public GroupingState deserialize(DataInputPlus in, int version, ClusteringComparator comparator) throws IOException |
| { |
| if (!in.readBoolean()) |
| return GroupingState.EMPTY_STATE; |
| |
| ByteBuffer partitionKey = ByteBufferUtil.readWithVIntLength(in); |
| Clustering<byte[]> clustering = null; |
| if (in.readBoolean()) |
| clustering = Clustering.serializer.deserialize(in, version, comparator.subtypes()); |
| |
| return new GroupingState(partitionKey, clustering); |
| } |
| |
| public long serializedSize(GroupingState state, int version, ClusteringComparator comparator) |
| { |
| boolean hasPartitionKey = state.partitionKey != null; |
| long size = TypeSizes.sizeof(hasPartitionKey); |
| if (hasPartitionKey) |
| { |
| size += ByteBufferUtil.serializedSizeWithVIntLength(state.partitionKey); |
| boolean hasClustering = state.hasClustering(); |
| size += TypeSizes.sizeof(hasClustering); |
| if (hasClustering) |
| { |
| size += Clustering.serializer.serializedSize(state.clustering, version, comparator.subtypes()); |
| } |
| } |
| return size; |
| } |
| } |
| } |