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 *     http://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
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package org.apache.cassandra.db.partitions;

import org.apache.cassandra.cache.IRowCacheEntry;
import org.apache.cassandra.db.rows.Row;
import org.apache.cassandra.io.ISerializer;

A partition stored in the partition cache. Note that in practice, the only implementation of this is CachedBTreePartition, we keep this interface mainly to make it clear what we need from partition in the cache (that we don't otherwise) /**
 * A partition stored in the partition cache.
 *
 * Note that in practice, the only implementation of this is {@link CachedBTreePartition},
 * we keep this interface mainly to make it clear what we need from partition in the cache
 * (that we don't otherwise)
 */
public interface CachedPartition extends Partition, IRowCacheEntry
{
    public static final ISerializer<CachedPartition> cacheSerializer = new CachedBTreePartition.Serializer();

    
The number of Row objects in this cached partition. Please note that this is not the number of live rows since
some of the row may only contains deleted (or expired) information.
Returns:
the number of row in the partition./**
     * The number of {@code Row} objects in this cached partition.
     *
     * Please note that this is <b>not</b> the number of <em>live</em> rows since
     * some of the row may only contains deleted (or expired) information.
     *
     * @return the number of row in the partition.
     */
    public int rowCount();

    
The number of rows that were live at the time the partition was cached. See ColumnFamilyStore.isFilterFullyCoveredBy to see why we need this. 
Returns:
the number of rows in this partition that were live at the time the
partition was cached (this can be different from the number of live rows now
due to expiring cells)./**
     * The number of rows that were live at the time the partition was cached.
     *
     * See {@link org.apache.cassandra.db.ColumnFamilyStore#isFilterFullyCoveredBy} to see why we need this.
     *
     * @return the number of rows in this partition that were live at the time the
     * partition was cached (this can be different from the number of live rows now
     * due to expiring cells).
     */
    public int cachedLiveRows();

    
The number of rows in this cached partition that have at least one non-expiring non-deleted cell. Note that this is generally not a very meaningful number, but this is used by DataLimits.hasEnoughLiveData as an optimization. 
Returns:
the number of row that have at least one non-expiring non-deleted cell./**
     * The number of rows in this cached partition that have at least one non-expiring
     * non-deleted cell.
     *
     * Note that this is generally not a very meaningful number, but this is used by
     * {@link org.apache.cassandra.db.filter.DataLimits#hasEnoughLiveData} as an optimization.
     *
     * @return the number of row that have at least one non-expiring non-deleted cell.
     */
    public int rowsWithNonExpiringCells();

    
The last row in this cached partition (in order words, the row with the
biggest clustering that the partition contains).
Returns:
the last row of the partition, or null if the partition is empty./**
     * The last row in this cached partition (in order words, the row with the
     * biggest clustering that the partition contains).
     *
     * @return the last row of the partition, or {@code null} if the partition is empty.
     */
    public Row lastRow();

    
The number of cell objects that are not tombstone in this cached partition. Please note that this is not the number of live cells since
some of the cells might be expired.
Returns:
the number of non tombstone cells in the partition./**
     * The number of {@code cell} objects that are not tombstone in this cached partition.
     *
     * Please note that this is <b>not</b> the number of <em>live</em> cells since
     * some of the cells might be expired.
     *
     * @return the number of non tombstone cells in the partition.
     */
    public int nonTombstoneCellCount();

    
The number of cells in this cached partition that are neither tombstone nor expiring. Note that this is generally not a very meaningful number, but this is used by DataLimits.hasEnoughLiveData as an optimization. 
Returns:
the number of cells that are neither tombstones nor expiring./**
     * The number of cells in this cached partition that are neither tombstone nor expiring.
     *
     * Note that this is generally not a very meaningful number, but this is used by
     * {@link org.apache.cassandra.db.filter.DataLimits#hasEnoughLiveData} as an optimization.
     *
     * @return the number of cells that are neither tombstones nor expiring.
     */
    public int nonExpiringLiveCells();
}