| /* |
| * 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.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 {@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 {@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 {@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 |
| * {@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). |
| * |
| * @return the last row of the partition, or {@code null} if the partition is empty. |
| */ |
| public Row lastRow(); |
| |
| /** |
| * 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 |
| * {@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(); |
| } |