org.apache.bookkeeper.mledger.impl.EntryCache Maven / Gradle / Ivy
/**
* 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.bookkeeper.mledger.impl;
import org.apache.bookkeeper.client.api.ReadHandle;
import org.apache.bookkeeper.mledger.AsyncCallbacks.ReadEntriesCallback;
import org.apache.bookkeeper.mledger.AsyncCallbacks.ReadEntryCallback;
import org.apache.commons.lang3.tuple.Pair;
/**
* Cache of entries used by a single ManagedLedger. An EntryCache is compared to other EntryCache instances using their
* size (the memory that is occupied by each of them).
*/
public interface EntryCache extends Comparable {
/**
* @return the name of the cache
*/
String getName();
/**
* Insert an entry in the cache.
*
* If the overall limit have been reached, this will triggered the eviction of other entries, possibly from
* other EntryCache instances
*
* @param entry
* the entry to be cached
* @return whether the entry was inserted in cache
*/
boolean insert(EntryImpl entry);
/**
* Remove from cache all the entries related to a ledger up to lastPosition included.
*
* @param lastPosition
* the position of the last entry to be invalidated (inclusive)
*/
void invalidateEntries(PositionImpl lastPosition);
/**
* Remove from the cache all the entries belonging to a specific ledger.
*
* @param ledgerId
* the ledger id
*/
void invalidateAllEntries(long ledgerId);
/**
* Remove all the entries from the cache.
*/
void clear();
/**
* Force the cache to drop entries to free space.
*
* @param sizeToFree
* the total memory size to free
* @return a pair containing the number of entries evicted and their total size
*/
Pair evictEntries(long sizeToFree);
/**
* Read entries from the cache or from bookkeeper.
*
* Get the entry data either from cache or bookkeeper and mixes up the results in a single list.
*
* @param lh
* the ledger handle
* @param firstEntry
* the first entry to read (inclusive)
* @param lastEntry
* the last entry to read (inclusive)
* @param isSlowestReader
* whether the reader cursor is the most far behind in the stream
* @param callback
* the callback object that will be notified when read is done
* @param ctx
* the context object
*/
void asyncReadEntry(ReadHandle lh, long firstEntry, long lastEntry, boolean isSlowestReader,
ReadEntriesCallback callback, Object ctx);
/**
* Read entry at given position from the cache or from bookkeeper.
*
* Get the entry data either from cache or bookkeeper and mixes up the results in a single list.
*
* @param lh
* the ledger handle
* @param position
* position to read the entry from
* @param callback
* the callback object that will be notified when read is done
* @param ctx
* the context object
*/
void asyncReadEntry(ReadHandle lh, PositionImpl position, ReadEntryCallback callback, Object ctx);
/**
* Get the total size in bytes of all the entries stored in this cache.
*
* @return the size of the entry cache
*/
long getSize();
}