| /* |
| * 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; |
| |
| import java.io.DataInput; |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| import org.apache.cassandra.config.DatabaseDescriptor; |
| import org.apache.cassandra.db.filter.IDiskAtomFilter; |
| import org.apache.cassandra.db.filter.NamesQueryFilter; |
| import org.apache.cassandra.db.filter.SliceQueryFilter; |
| import org.apache.cassandra.io.IVersionedSerializer; |
| import org.apache.cassandra.io.util.DataOutputPlus; |
| import org.apache.cassandra.net.MessageOut; |
| import org.apache.cassandra.net.MessagingService; |
| import org.apache.cassandra.service.IReadCommand; |
| import org.apache.cassandra.service.RowDataResolver; |
| import org.apache.cassandra.service.pager.Pageable; |
| |
| public abstract class ReadCommand implements IReadCommand, Pageable |
| { |
| public enum Type |
| { |
| GET_BY_NAMES((byte)1), |
| GET_SLICES((byte)2); |
| |
| public final byte serializedValue; |
| |
| private Type(byte b) |
| { |
| this.serializedValue = b; |
| } |
| |
| public static Type fromSerializedValue(byte b) |
| { |
| return b == 1 ? GET_BY_NAMES : GET_SLICES; |
| } |
| } |
| |
| public static final ReadCommandSerializer serializer = new ReadCommandSerializer(); |
| |
| public MessageOut<ReadCommand> createMessage() |
| { |
| return new MessageOut<>(MessagingService.Verb.READ, this, serializer); |
| } |
| |
| public final String ksName; |
| public final String cfName; |
| public final ByteBuffer key; |
| public final long timestamp; |
| private boolean isDigestQuery = false; |
| protected final Type commandType; |
| |
| protected ReadCommand(String ksName, ByteBuffer key, String cfName, long timestamp, Type cmdType) |
| { |
| this.ksName = ksName; |
| this.key = key; |
| this.cfName = cfName; |
| this.timestamp = timestamp; |
| this.commandType = cmdType; |
| } |
| |
| public static ReadCommand create(String ksName, ByteBuffer key, String cfName, long timestamp, IDiskAtomFilter filter) |
| { |
| if (filter instanceof SliceQueryFilter) |
| return new SliceFromReadCommand(ksName, key, cfName, timestamp, (SliceQueryFilter)filter); |
| else |
| return new SliceByNamesReadCommand(ksName, key, cfName, timestamp, (NamesQueryFilter)filter); |
| } |
| |
| public boolean isDigestQuery() |
| { |
| return isDigestQuery; |
| } |
| |
| public ReadCommand setIsDigestQuery(boolean isDigestQuery) |
| { |
| this.isDigestQuery = isDigestQuery; |
| return this; |
| } |
| |
| public String getColumnFamilyName() |
| { |
| return cfName; |
| } |
| |
| public abstract ReadCommand copy(); |
| |
| public abstract Row getRow(Keyspace keyspace); |
| |
| public abstract IDiskAtomFilter filter(); |
| |
| public String getKeyspace() |
| { |
| return ksName; |
| } |
| |
| // maybeGenerateRetryCommand is used to generate a retry for short reads |
| public ReadCommand maybeGenerateRetryCommand(RowDataResolver resolver, Row row) |
| { |
| return null; |
| } |
| |
| // maybeTrim removes columns from a response that is too long |
| public Row maybeTrim(Row row) |
| { |
| return row; |
| } |
| |
| public long getTimeout() |
| { |
| return DatabaseDescriptor.getReadRpcTimeout(); |
| } |
| } |
| |
| class ReadCommandSerializer implements IVersionedSerializer<ReadCommand> |
| { |
| public void serialize(ReadCommand command, DataOutputPlus out, int version) throws IOException |
| { |
| out.writeByte(command.commandType.serializedValue); |
| switch (command.commandType) |
| { |
| case GET_BY_NAMES: |
| SliceByNamesReadCommand.serializer.serialize(command, out, version); |
| break; |
| case GET_SLICES: |
| SliceFromReadCommand.serializer.serialize(command, out, version); |
| break; |
| default: |
| throw new AssertionError(); |
| } |
| } |
| |
| public ReadCommand deserialize(DataInput in, int version) throws IOException |
| { |
| ReadCommand.Type msgType = ReadCommand.Type.fromSerializedValue(in.readByte()); |
| switch (msgType) |
| { |
| case GET_BY_NAMES: |
| return SliceByNamesReadCommand.serializer.deserialize(in, version); |
| case GET_SLICES: |
| return SliceFromReadCommand.serializer.deserialize(in, version); |
| default: |
| throw new AssertionError(); |
| } |
| } |
| |
| public long serializedSize(ReadCommand command, int version) |
| { |
| switch (command.commandType) |
| { |
| case GET_BY_NAMES: |
| return 1 + SliceByNamesReadCommand.serializer.serializedSize(command, version); |
| case GET_SLICES: |
| return 1 + SliceFromReadCommand.serializer.serializedSize(command, version); |
| default: |
| throw new AssertionError(); |
| } |
| } |
| } |