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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;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.twitter.distributedlog.exceptions.LogRecordTooLongException;
import com.twitter.distributedlog.exceptions.WriteException;
import com.twitter.distributedlog.io.CompressionCodec;
import com.twitter.util.Promise;
import org.apache.bookkeeper.stats.NullStatsLogger;
import org.apache.bookkeeper.stats.StatsLogger;
import javax.annotation.Nullable;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* A set of {@link LogRecord}s.
*/
public class Entry {
/**
* Create a new log record set.
*
* @param logName
* name of the log
* @param initialBufferSize
* initial buffer size
* @param envelopeBeforeTransmit
* if envelope the buffer before transmit
* @param codec
* compression codec
* @param statsLogger
* stats logger to receive stats
* @return writer to build a log record set.
*/
public static Writer newEntry(
String logName,
int initialBufferSize,
boolean envelopeBeforeTransmit,
CompressionCodec.Type codec,
StatsLogger statsLogger) {
return new EnvelopedEntryWriter(
logName,
initialBufferSize,
envelopeBeforeTransmit,
codec,
statsLogger);
}
public static Builder newBuilder() {
return new Builder();
}
/**
* Build the record set object.
*/
public static class Builder {
private long logSegmentSequenceNumber = -1;
private long entryId = -1;
private long startSequenceId = Long.MIN_VALUE;
private boolean envelopeEntry = true;
// input stream
private InputStream in = null;
// or bytes array
private byte[] data = null;
private int offset = -1;
private int length = -1;
private Optional txidToSkipTo = Optional.absent();
private Optional dlsnToSkipTo = Optional.absent();
private boolean deserializeRecordSet = true;
private Builder() {}
/**
* Reset the builder.
*
* @return builder
*/
public Builder reset() {
logSegmentSequenceNumber = -1;
entryId = -1;
startSequenceId = Long.MIN_VALUE;
envelopeEntry = true;
// input stream
in = null;
// or bytes array
data = null;
offset = -1;
length = -1;
txidToSkipTo = Optional.absent();
dlsnToSkipTo = Optional.absent();
return this;
}
/**
* Set the segment info of the log segment that this record
* set belongs to.
*
* @param lssn
* log segment sequence number
* @param startSequenceId
* start sequence id of this log segment
* @return builder
*/
public Builder setLogSegmentInfo(long lssn, long startSequenceId) {
this.logSegmentSequenceNumber = lssn;
this.startSequenceId = startSequenceId;
return this;
}
/**
* Set the entry id of this log record set.
*
* @param entryId
* entry id assigned for this log record set.
* @return builder
*/
public Builder setEntryId(long entryId) {
this.entryId = entryId;
return this;
}
/**
* Set whether this record set is enveloped or not.
*
* @param enabled
* flag indicates whether this record set is enveloped or not.
* @return builder
*/
public Builder setEnvelopeEntry(boolean enabled) {
this.envelopeEntry = enabled;
return this;
}
/**
* Set the serialized bytes data of this record set.
*
* @param data
* serialized bytes data of this record set.
* @param offset
* offset of the bytes data
* @param length
* length of the bytes data
* @return builder
*/
public Builder setData(byte[] data, int offset, int length) {
this.data = data;
this.offset = offset;
this.length = length;
return this;
}
/**
* Set the input stream of the serialized bytes data of this record set.
*
* @param in
* input stream
* @return builder
*/
public Builder setInputStream(InputStream in) {
this.in = in;
return this;
}
/**
* Set the record set starts from dlsn.
*
* @param dlsn
* dlsn to skip to
* @return builder
*/
public Builder skipTo(@Nullable DLSN dlsn) {
this.dlsnToSkipTo = Optional.fromNullable(dlsn);
return this;
}
/**
* Set the record set starts from txid.
*
* @param txid
* txid to skip to
* @return builder
*/
public Builder skipTo(long txid) {
this.txidToSkipTo = Optional.of(txid);
return this;
}
/**
* Enable/disable deserialize record set.
*
* @param enabled
* flag to enable/disable dserialize record set.
* @return builder
*/
public Builder deserializeRecordSet(boolean enabled) {
this.deserializeRecordSet = enabled;
return this;
}
public Entry build() {
Preconditions.checkNotNull(data, "Serialized data isn't provided");
Preconditions.checkArgument(offset >= 0 && length >= 0
&& (offset + length) <= data.length,
"Invalid offset or length of serialized data");
return new Entry(
logSegmentSequenceNumber,
entryId,
startSequenceId,
envelopeEntry,
deserializeRecordSet,
data,
offset,
length,
txidToSkipTo,
dlsnToSkipTo);
}
public Entry.Reader buildReader() throws IOException {
Preconditions.checkArgument(data != null || in != null,
"Serialized data or input stream isn't provided");
InputStream in;
if (null != this.in) {
in = this.in;
} else {
Preconditions.checkArgument(offset >= 0 && length >= 0
&& (offset + length) <= data.length,
"Invalid offset or length of serialized data");
in = new ByteArrayInputStream(data, offset, length);
}
return new EnvelopedEntryReader(
logSegmentSequenceNumber,
entryId,
startSequenceId,
in,
envelopeEntry,
deserializeRecordSet,
NullStatsLogger.INSTANCE);
}
}
private final long logSegmentSequenceNumber;
private final long entryId;
private final long startSequenceId;
private final boolean envelopedEntry;
private final boolean deserializeRecordSet;
private final byte[] data;
private final int offset;
private final int length;
private final Optional txidToSkipTo;
private final Optional dlsnToSkipTo;
private Entry(long logSegmentSequenceNumber,
long entryId,
long startSequenceId,
boolean envelopedEntry,
boolean deserializeRecordSet,
byte[] data,
int offset,
int length,
Optional txidToSkipTo,
Optional dlsnToSkipTo) {
this.logSegmentSequenceNumber = logSegmentSequenceNumber;
this.entryId = entryId;
this.startSequenceId = startSequenceId;
this.envelopedEntry = envelopedEntry;
this.deserializeRecordSet = deserializeRecordSet;
this.data = data;
this.offset = offset;
this.length = length;
this.txidToSkipTo = txidToSkipTo;
this.dlsnToSkipTo = dlsnToSkipTo;
}
/**
* Get raw data of this record set.
*
* @return raw data representation of this record set.
*/
public byte[] getRawData() {
return data;
}
/**
* Create reader to iterate over this record set.
*
* @return reader to iterate over this record set.
* @throws IOException if the record set is invalid record set.
*/
public Reader reader() throws IOException {
InputStream in = new ByteArrayInputStream(data, offset, length);
Reader reader = new EnvelopedEntryReader(
logSegmentSequenceNumber,
entryId,
startSequenceId,
in,
envelopedEntry,
deserializeRecordSet,
NullStatsLogger.INSTANCE);
if (txidToSkipTo.isPresent()) {
reader.skipTo(txidToSkipTo.get());
}
if (dlsnToSkipTo.isPresent()) {
reader.skipTo(dlsnToSkipTo.get());
}
return reader;
}
/**
* Writer to append {@link LogRecord}s to {@link Entry}.
*/
public interface Writer extends EntryBuffer {
/**
* Write a {@link LogRecord} to this record set.
*
* @param record
* record to write
* @param transmitPromise
* callback for transmit result. the promise is only
* satisfied when this record set is transmitted.
* @throws LogRecordTooLongException if the record is too long
* @throws WriteException when encountered exception writing the record
*/
void writeRecord(LogRecord record, Promise transmitPromise)
throws LogRecordTooLongException, WriteException;
/**
* Reset the writer to write records.
*/
void reset();
}
/**
* Reader to read {@link LogRecord}s from this record set.
*/
public interface Reader {
/**
* Read next log record from this record set.
*
* @return next log record from this record set.
*/
LogRecordWithDLSN nextRecord() throws IOException;
/**
* Skip the reader to the record whose transaction id is txId.
*
* @param txId
* transaction id to skip to.
* @return true if skip succeeds, otherwise false.
* @throws IOException
*/
boolean skipTo(long txId) throws IOException;
/**
* Skip the reader to the record whose DLSN is dlsn.
*
* @param dlsn
* DLSN to skip to.
* @return true if skip succeeds, otherwise false.
* @throws IOException
*/
boolean skipTo(DLSN dlsn) throws IOException;
}
}
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