forked from apache/ratis
/
LogReaderImpl.java
187 lines (164 loc) · 5.95 KB
/
LogReaderImpl.java
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/**
* 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.ratis.logservice.impl;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import org.apache.ratis.client.RaftClient;
import org.apache.ratis.logservice.api.LogReader;
import org.apache.ratis.logservice.api.LogServiceConfiguration;
import org.apache.ratis.logservice.api.LogStream;
import org.apache.ratis.logservice.proto.LogServiceProtos.*;
import org.apache.ratis.logservice.util.LogServiceProtoUtil;
import org.apache.ratis.protocol.Message;
import org.apache.ratis.protocol.RaftClientReply;
import org.apache.ratis.thirdparty.com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Log Reader implementation. This class is not thread-safe
*
*/
public class LogReaderImpl implements LogReader {
public static final Logger LOG = LoggerFactory.getLogger(LogReaderImpl.class);
/*
* Parent log stream
*/
private LogStream parent;
/*
* Raft client
*/
private RaftClient raftClient;
/*
* Log service configuration object
*/
private LogServiceConfiguration config;
/*
* offset
*/
long currentRecordId;
public LogReaderImpl(LogStream logStream) {
this.parent = logStream;
this.raftClient = logStream.getRaftClient();
this.config = logStream.getConfiguration();
}
@Override
public void seek(long recordId) throws IOException {
Preconditions.checkArgument(recordId >= 0, "recordId must be >= 0");
this.currentRecordId = recordId;
}
@Override
public ByteBuffer readNext() throws IOException {
try {
RaftClientReply reply =
raftClient
.sendReadOnly(Message.valueOf(LogServiceProtoUtil
.toReadLogRequestProto(parent.getName(), currentRecordId, 1).toByteString()));
ReadLogReplyProto proto = ReadLogReplyProto.parseFrom(reply.getMessage().getContent());
if (proto.hasException()) {
LogServiceException e = proto.getException();
throw new IOException(e.getErrorMsg());
}
currentRecordId++;
if (proto.getLogRecordCount() > 0) {
proto.getLogRecord(0);
return ByteBuffer.wrap(proto.getLogRecord(0).toByteArray());
} else {
return null;
}
} catch (Exception e) {
throw new IOException(e);
}
}
@Override
public void readNext(ByteBuffer buffer) throws IOException {
Preconditions.checkNotNull(buffer, "buffer is NULL" );
try {
RaftClientReply reply = raftClient.sendReadOnly(Message.valueOf(LogServiceProtoUtil
.toReadLogRequestProto(parent.getName(), currentRecordId, 1).toByteString()));
ReadLogReplyProto proto = ReadLogReplyProto.parseFrom(reply.getMessage().getContent());
if (proto.hasException()) {
LogServiceException e = proto.getException();
throw new IOException(e.getErrorMsg());
}
currentRecordId++;
if (proto.getLogRecordCount() > 0) {
// TODO limits
buffer.put(proto.getLogRecord(0).toByteArray());
}
} catch (Exception e) {
throw new IOException(e);
}
}
@Override
public List<ByteBuffer> readBulk(int numRecords) throws IOException {
Preconditions.checkArgument(numRecords > 0, "number of records must be greater than 0");
try {
RaftClientReply reply = raftClient
.sendReadOnly(Message.valueOf(LogServiceProtoUtil
.toReadLogRequestProto(parent.getName(), currentRecordId, numRecords).toByteString()));
ReadLogReplyProto proto = ReadLogReplyProto.parseFrom(reply.getMessage().getContent());
if (proto.hasException()) {
LogServiceException e = proto.getException();
throw new IOException(e.getErrorMsg());
}
int n = proto.getLogRecordCount();
// TODO correct current record
currentRecordId += n;
List<ByteBuffer> ret = new ArrayList<ByteBuffer>();
for (int i = 0; i < n; i++) {
ret.add(ByteBuffer.wrap(proto.getLogRecord(i).toByteArray()));
}
return ret;
} catch (Exception e) {
throw new IOException(e);
}
}
@Override
public int readBulk(ByteBuffer[] buffers) throws IOException {
Preconditions.checkNotNull(buffers, "list of buffers is NULL" );
Preconditions.checkArgument(buffers.length > 0, "list of buffers is empty");
try {
RaftClientReply reply = raftClient.sendReadOnly(Message.valueOf(LogServiceProtoUtil
.toReadLogRequestProto(parent.getName(), currentRecordId, buffers.length).toByteString()));
ReadLogReplyProto proto = ReadLogReplyProto.parseFrom(reply.getMessage().getContent());
if (proto.hasException()) {
LogServiceException e = proto.getException();
throw new IOException(e.getErrorMsg());
}
// TODO correct current record
int n = proto.getLogRecordCount();
currentRecordId += n;
for (int i = 0; i < n; i++) {
buffers[i] = ByteBuffer.wrap(proto.getLogRecord(i).toByteArray());
}
return n;
} catch (Exception e) {
throw new IOException(e);
}
}
@Override
public long getPosition() {
return currentRecordId;
}
@Override
public void close() throws IOException {
// TODO Auto-generated method stub
}
}