com.twitter.distributedlog.util.DLUtils Maven / Gradle / Ivy
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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 com.twitter.distributedlog.util;
import com.twitter.distributedlog.LogSegmentMetadata;
import com.twitter.distributedlog.exceptions.UnexpectedException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.net.URI;
import java.util.List;
import static com.google.common.base.Charsets.UTF_8;
/**
* Utilities about DL implementations like uri, log segments, metadata serialization and deserialization.
*/
public class DLUtils {
static final Logger logger = LoggerFactory.getLogger(DLUtils.class);
/**
* Extract zk servers fro dl uri.
*
* @param uri
* dl uri
* @return zk servers
*/
public static String getZKServersFromDLUri(URI uri) {
return uri.getAuthority().replace(";", ",");
}
/**
* Find the log segment whose transaction ids are not less than provided transactionId.
*
* @param segments
* segments to search
* @param transactionId
* transaction id to find
* @return the first log segment whose transaction ids are not less than transactionId.
*/
public static int findLogSegmentNotLessThanTxnId(List segments,
long transactionId) {
int found = -1;
for (int i = segments.size() - 1; i >= 0; i--) {
LogSegmentMetadata segment = segments.get(i);
if (segment.getFirstTxId() <= transactionId) {
found = i;
break;
}
}
if (found <= -1) {
return -1;
}
if (found == 0 && segments.get(0).getFirstTxId() == transactionId) {
return 0;
}
LogSegmentMetadata foundSegment = segments.get(found);
if (foundSegment.getFirstTxId() == transactionId) {
for (int i = found - 1; i >= 0; i--) {
LogSegmentMetadata segment = segments.get(i);
if (segment.isInProgress()) {
break;
}
if (segment.getLastTxId() < transactionId) {
break;
}
found = i;
}
return found;
} else {
if (foundSegment.isInProgress()
|| found == segments.size() - 1) {
return found;
}
if (foundSegment.getLastTxId() >= transactionId) {
return found;
}
return found + 1;
}
}
/**
* Assign next log segment sequence number based on a decreasing list of log segments.
*
* @param segmentListDesc
* a decreasing list of log segments
* @return null if no log segments was assigned a sequence number in segmentListDesc.
* otherwise, return next log segment sequence number
*/
public static Long nextLogSegmentSequenceNumber(List segmentListDesc) {
int lastAssignedLogSegmentIdx = -1;
Long lastAssignedLogSegmentSeqNo = null;
Long nextLogSegmentSeqNo = null;
for (int i = 0; i < segmentListDesc.size(); i++) {
LogSegmentMetadata metadata = segmentListDesc.get(i);
if (LogSegmentMetadata.supportsLogSegmentSequenceNo(metadata.getVersion())) {
lastAssignedLogSegmentSeqNo = metadata.getLogSegmentSequenceNumber();
lastAssignedLogSegmentIdx = i;
break;
}
}
if (null != lastAssignedLogSegmentSeqNo) {
// latest log segment is assigned with a sequence number, start with next sequence number
nextLogSegmentSeqNo = lastAssignedLogSegmentSeqNo + lastAssignedLogSegmentIdx + 1;
}
return nextLogSegmentSeqNo;
}
/**
* Compute the start sequence id for segment, based on previous segment list
* segmentListDesc.
*
* @param logSegmentDescList
* list of segments in descending order
* @param segment
* segment to compute start sequence id for
* @return start sequence id
*/
public static long computeStartSequenceId(List logSegmentDescList,
LogSegmentMetadata segment)
throws UnexpectedException {
long startSequenceId = 0L;
for (LogSegmentMetadata metadata : logSegmentDescList) {
if (metadata.getLogSegmentSequenceNumber() >= segment.getLogSegmentSequenceNumber()) {
continue;
} else if (metadata.getLogSegmentSequenceNumber() < (segment.getLogSegmentSequenceNumber() - 1)) {
break;
}
if (metadata.isInProgress()) {
throw new UnexpectedException("Should not complete log segment " + segment.getLogSegmentSequenceNumber()
+ " since it's previous log segment is still inprogress : " + logSegmentDescList);
}
if (metadata.supportsSequenceId()) {
startSequenceId = metadata.getStartSequenceId() + metadata.getRecordCount();
}
}
return startSequenceId;
}
/**
* Deserialize log segment sequence number for bytes data.
*
* @param data
* byte representation of log segment sequence number
* @return log segment sequence number
* @throws NumberFormatException if the bytes aren't valid
*/
public static long deserializeLogSegmentSequenceNumber(byte[] data) {
String seqNoStr = new String(data, UTF_8);
return Long.valueOf(seqNoStr);
}
/**
* Serilize log segment sequence number logSegmentSeqNo into bytes.
*
* @param logSegmentSeqNo
* log segment sequence number
* @return byte representation of log segment sequence number
*/
public static byte[] serializeLogSegmentSequenceNumber(long logSegmentSeqNo) {
return Long.toString(logSegmentSeqNo).getBytes(UTF_8);
}
/**
* Deserialize log record transaction id for bytes data.
*
* @param data
* byte representation of log record transaction id
* @return log record transaction id
* @throws NumberFormatException if the bytes aren't valid
*/
public static long deserializeTransactionId(byte[] data) {
String seqNoStr = new String(data, UTF_8);
return Long.valueOf(seqNoStr);
}
/**
* Serilize log record transaction id transactionId into bytes.
*
* @param transactionId
* log record transaction id
* @return byte representation of log record transaction id.
*/
public static byte[] serializeTransactionId(long transactionId) {
return Long.toString(transactionId).getBytes(UTF_8);
}
/**
* Serialize ledger id into bytes.
*
* @param ledgerId
* ledger id
* @return bytes representation of ledger id
*/
public static byte[] ledgerId2Bytes(long ledgerId) {
return Long.toString(ledgerId).getBytes(UTF_8);
}
/**
* Deserialize bytes into ledger id.
*
* @param data
* bytes representation of ledger id
* @return ledger id
*/
public static long bytes2LedgerId(byte[] data) {
return Long.valueOf(new String(data, UTF_8));
}
}
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