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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.cassandra.db.rows;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Comparator;
import org.apache.cassandra.config.ColumnDefinition;
import org.apache.cassandra.db.*;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.utils.memory.AbstractAllocator;
/**
* A cell is our atomic unit for a single value of a single column.
*
* A cell always holds at least a timestamp that gives us how the cell reconcile. We then
* have 3 main types of cells:
* 1) live regular cells: those will also have a value and, if for a complex column, a path.
* 2) expiring cells: on top of regular cells, those have a ttl and a local deletion time (when they are expired).
* 3) tombstone cells: those won't have value, but they have a local deletion time (when the tombstone was created).
*/
public abstract class Cell extends ColumnData
{
public static final int NO_TTL = 0;
public static final int NO_DELETION_TIME = Integer.MAX_VALUE;
public final static Comparator comparator = (c1, c2) ->
{
int cmp = c1.column().compareTo(c2.column());
if (cmp != 0)
return cmp;
Comparator pathComparator = c1.column().cellPathComparator();
return pathComparator == null ? 0 : pathComparator.compare(c1.path(), c2.path());
};
public static final Serializer serializer = new BufferCell.Serializer();
protected Cell(ColumnDefinition column)
{
super(column);
}
/**
* Whether the cell is a counter cell or not.
*
* @return whether the cell is a counter cell or not.
*/
public abstract boolean isCounterCell();
/**
* The cell value.
*
* @return the cell value.
*/
public abstract ByteBuffer value();
/**
* The cell timestamp.
*
* @return the cell timestamp.
*/
public abstract long timestamp();
/**
* The cell ttl.
*
* @return the cell ttl, or {@code NO_TTL} if the cell isn't an expiring one.
*/
public abstract int ttl();
/**
* The cell local deletion time.
*
* @return the cell local deletion time, or {@code NO_DELETION_TIME} if the cell is neither
* a tombstone nor an expiring one.
*/
public abstract int localDeletionTime();
/**
* Whether the cell is a tombstone or not.
*
* @return whether the cell is a tombstone or not.
*/
public abstract boolean isTombstone();
/**
* Whether the cell is an expiring one or not.
*
* Note that this only correspond to whether the cell liveness info
* have a TTL or not, but doesn't tells whether the cell is already expired
* or not. You should use {@link #isLive} for that latter information.
*
* @return whether the cell is an expiring one or not.
*/
public abstract boolean isExpiring();
/**
* Whether the cell is live or not given the current time.
*
* @param nowInSec the current time in seconds. This is used to
* decide if an expiring cell is expired or live.
* @return whether the cell is live or not at {@code nowInSec}.
*/
public abstract boolean isLive(int nowInSec);
/**
* For cells belonging to complex types (non-frozen collection and UDT), the
* path to the cell.
*
* @return the cell path for cells of complex column, and {@code null} for other cells.
*/
public abstract CellPath path();
public abstract Cell withUpdatedColumn(ColumnDefinition newColumn);
public abstract Cell withUpdatedValue(ByteBuffer newValue);
public abstract Cell copy(AbstractAllocator allocator);
@Override
// Overrides super type to provide a more precise return type.
public abstract Cell markCounterLocalToBeCleared();
@Override
// Overrides super type to provide a more precise return type.
public abstract Cell purge(DeletionPurger purger, int nowInSec);
public interface Serializer
{
public void serialize(Cell cell, ColumnDefinition column, DataOutputPlus out, LivenessInfo rowLiveness, SerializationHeader header) throws IOException;
public Cell deserialize(DataInputPlus in, LivenessInfo rowLiveness, ColumnDefinition column, SerializationHeader header, SerializationHelper helper) throws IOException;
public long serializedSize(Cell cell, ColumnDefinition column, LivenessInfo rowLiveness, SerializationHeader header);
// Returns if the skipped cell was an actual cell (i.e. it had its presence flag).
public boolean skip(DataInputPlus in, ColumnDefinition column, SerializationHeader header) throws IOException;
}
}
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