org.apache.cassandra.io.sstable.SequenceBasedSSTableId Maven / Gradle / Ivy
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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.io.sstable;
import java.nio.ByteBuffer;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Supplier;
import java.util.regex.Pattern;
import java.util.stream.Stream;
import com.google.common.base.Preconditions;
/**
* Generation identifier based on sequence of integers.
* This has been the standard implementation in C* since inception.
*/
public class SequenceBasedSSTableId implements SSTableId, Comparable
{
public final int generation;
public SequenceBasedSSTableId(final int generation)
{
assert generation >= 0;
this.generation = generation;
}
@Override
public int compareTo(SequenceBasedSSTableId o)
{
if (o == null)
return 1;
else if (o == this)
return 0;
return Integer.compare(this.generation, o.generation);
}
@Override
public boolean equals(Object o)
{
if (this == o) return true;
if (o == null || getClass() != o.getClass())
return false;
SequenceBasedSSTableId that = (SequenceBasedSSTableId) o;
return generation == that.generation;
}
@Override
public int hashCode()
{
return Objects.hash(generation);
}
@Override
public ByteBuffer asBytes()
{
ByteBuffer bytes = ByteBuffer.allocate(Integer.BYTES);
bytes.putInt(0, generation);
return bytes;
}
@Override
public String toString()
{
return String.valueOf(generation);
}
public static class Builder implements SSTableId.Builder
{
public final static Builder instance = new Builder();
private final static Pattern PATTERN = Pattern.compile("\\d+");
/**
* Generates a sequential number to represent an sstables identifier. The first generated identifier will be
* greater by one than the largest generation number found across the provided existing identifiers.
*/
@Override
public Supplier generator(Stream existingIdentifiers)
{
int value = existingIdentifiers.filter(SequenceBasedSSTableId.class::isInstance)
.map(SequenceBasedSSTableId.class::cast)
.mapToInt(id -> id.generation)
.max()
.orElse(0);
AtomicInteger fileIndexGenerator = new AtomicInteger(value);
return () -> new SequenceBasedSSTableId(fileIndexGenerator.incrementAndGet());
}
@Override
public boolean isUniqueIdentifier(String str)
{
return str != null && !str.isEmpty() && str.length() <= 10 && PATTERN.matcher(str).matches();
}
@Override
public boolean isUniqueIdentifier(ByteBuffer bytes)
{
return bytes != null && bytes.remaining() == Integer.BYTES && bytes.getInt(0) >= 0;
}
@Override
public SequenceBasedSSTableId fromString(String token) throws IllegalArgumentException
{
return new SequenceBasedSSTableId(Integer.parseInt(token));
}
@Override
public SequenceBasedSSTableId fromBytes(ByteBuffer bytes) throws IllegalArgumentException
{
Preconditions.checkArgument(bytes.remaining() == Integer.BYTES, "Buffer does not have a valid number of bytes remaining. Expecting: %s but was: %s", Integer.BYTES, bytes.remaining());
return new SequenceBasedSSTableId(bytes.getInt(0));
}
}
}