/*
* 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.IOError;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.security.MessageDigest;
import java.util.Iterator;
import com.google.common.collect.AbstractIterator;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.db.composites.CellName;
import org.apache.cassandra.db.composites.CellNameType;
import org.apache.cassandra.db.marshal.*;
import org.apache.cassandra.io.sstable.Descriptor;
import org.apache.cassandra.io.util.DataOutputBuffer;
import org.apache.cassandra.serializers.MarshalException;
import org.apache.cassandra.utils.Allocator;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.HeapAllocator;
/**
* Cell is immutable, which prevents all kinds of confusion in a multithreaded environment.
*/
public class Cell implements OnDiskAtom
{
public static final int MAX_NAME_LENGTH = FBUtilities.MAX_UNSIGNED_SHORT;
/**
* For 2.0-formatted sstables (where column count is not stored), @param count should be Integer.MAX_VALUE,
* and we will look for the end-of-row column name marker instead of relying on that.
*/
public static Iterator<OnDiskAtom> onDiskIterator(final DataInput in,
final int count,
final ColumnSerializer.Flag flag,
final int expireBefore,
final Descriptor.Version version,
final CellNameType type)
{
return new AbstractIterator<OnDiskAtom>()
{
int i = 0;
protected OnDiskAtom computeNext()
{
if (i++ >= count)
return endOfData();
OnDiskAtom atom;
try
{
atom = type.onDiskAtomSerializer().deserializeFromSSTable(in, flag, expireBefore, version);
}
catch (IOException e)
{
throw new IOError(e);
}
if (atom == null)
return endOfData();
return atom;
}
};
}
protected final CellName name;
protected final ByteBuffer value;
protected final long timestamp;
Cell(CellName name)
{
this(name, ByteBufferUtil.EMPTY_BYTE_BUFFER);
}
public Cell(CellName name, ByteBuffer value)
{
this(name, value, 0);
}
public Cell(CellName name, ByteBuffer value, long timestamp)
{
assert name != null;
assert value != null;
this.name = name;
this.value = value;
this.timestamp = timestamp;
}
public Cell withUpdatedName(CellName newName)
{
return new Cell(newName, value, timestamp);
}
public Cell withUpdatedTimestamp(long newTimestamp)
{
return new Cell(name, value, newTimestamp);
}
public CellName name()
{
return name;
}
public ByteBuffer value()
{
return value;
}
public long timestamp()
{
return timestamp;
}
public long minTimestamp()
{
return timestamp;
}
public long maxTimestamp()
{
return timestamp;
}
public boolean isMarkedForDelete(long now)
{
return false;
}
public boolean isLive(long now)
{
return !isMarkedForDelete(now);
}
// Don't call unless the column is actually marked for delete.
public long getMarkedForDeleteAt()
{
return Long.MAX_VALUE;
}
public int dataSize()
{
return name().dataSize() + value.remaining() + TypeSizes.NATIVE.sizeof(timestamp);
}
public int serializedSize(CellNameType type, TypeSizes typeSizes)
{
/*
* Size of a column is =
* size of a name (short + length of the string)
* + 1 byte to indicate if the column has been deleted
* + 8 bytes for timestamp
* + 4 bytes which basically indicates the size of the byte array
* + entire byte array.
*/
int valueSize = value.remaining();
return ((int)type.cellSerializer().serializedSize(name, typeSizes)) + 1 + typeSizes.sizeof(timestamp) + typeSizes.sizeof(valueSize) + valueSize;
}
public int serializationFlags()
{
return 0;
}
public Cell diff(Cell cell)
{
if (timestamp() < cell.timestamp())
return cell;
return null;
}
public void updateDigest(MessageDigest digest)
{
digest.update(name.toByteBuffer().duplicate());
digest.update(value.duplicate());
DataOutputBuffer buffer = new DataOutputBuffer();
try
{
buffer.writeLong(timestamp);
buffer.writeByte(serializationFlags());
}
catch (IOException e)
{
throw new RuntimeException(e);
}
digest.update(buffer.getData(), 0, buffer.getLength());
}
public int getLocalDeletionTime()
{
return Integer.MAX_VALUE;
}
public Cell reconcile(Cell cell)
{
return reconcile(cell, HeapAllocator.instance);
}
public Cell reconcile(Cell cell, Allocator allocator)
{
// tombstones take precedence. (if both are tombstones, then it doesn't matter which one we use.)
if (isMarkedForDelete(System.currentTimeMillis()))
return timestamp() < cell.timestamp() ? cell : this;
if (cell.isMarkedForDelete(System.currentTimeMillis()))
return timestamp() > cell.timestamp() ? this : cell;
// break ties by comparing values.
if (timestamp() == cell.timestamp())
return value().compareTo(cell.value()) < 0 ? cell : this;
// neither is tombstoned and timestamps are different
return timestamp() < cell.timestamp() ? cell : this;
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
if (o == null || getClass() != o.getClass())
return false;
Cell cell = (Cell)o;
if (timestamp != cell.timestamp)
return false;
if (!name.equals(cell.name))
return false;
return value.equals(cell.value);
}
@Override
public int hashCode()
{
int result = name != null ? name.hashCode() : 0;
result = 31 * result + (value != null ? value.hashCode() : 0);
result = 31 * result + (int)(timestamp ^ (timestamp >>> 32));
return result;
}
public Cell localCopy(ColumnFamilyStore cfs)
{
return localCopy(cfs, HeapAllocator.instance);
}
public Cell localCopy(ColumnFamilyStore cfs, Allocator allocator)
{
return new Cell(name.copy(allocator), allocator.clone(value), timestamp);
}
public String getString(CellNameType comparator)
{
return String.format("%s:%b:%d@%d",
comparator.getString(name),
isMarkedForDelete(System.currentTimeMillis()),
value.remaining(),
timestamp);
}
protected void validateName(CFMetaData metadata) throws MarshalException
{
metadata.comparator.validate(name());
}
public void validateFields(CFMetaData metadata) throws MarshalException
{
validateName(metadata);
AbstractType<?> valueValidator = metadata.getValueValidator(name());
if (valueValidator != null)
valueValidator.validate(value());
}
public boolean hasIrrelevantData(int gcBefore)
{
return getLocalDeletionTime() < gcBefore;
}
public static Cell create(CellName name, ByteBuffer value, long timestamp, int ttl, CFMetaData metadata)
{
if (ttl <= 0)
ttl = metadata.getDefaultTimeToLive();
return ttl > 0
? new ExpiringCell(name, value, timestamp, ttl)
: new Cell(name, value, timestamp);
}
}