org.apache.jackrabbit.mk.persistence.GCPersistence Maven / Gradle / Ivy
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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.jackrabbit.mk.persistence;
import org.apache.jackrabbit.mk.model.Commit;
import org.apache.jackrabbit.mk.model.Id;
/**
* Advanced persistence implementation offering GC support.
*
* The persistence implementation must ensure that objects written between {@link #start()}
* and {@link #sweep()} are not swept, in other words, they must be marked implicitely.
*/
public interface GCPersistence extends Persistence {
/**
* Start a GC cycle. All objects written to the persistence in subsequent calls are
* marked implicitely, i.e. they must be retained on {@link #sweep()}.
*/
void start();
/**
* Mark a commit.
*
* @param id
* commit id
* @return {@code true} if the commit was not marked before;
* {@code false} otherwise
*
* @throws Exception if an error occurs
*/
boolean markCommit(Id id) throws Exception;
/**
* Replace a commit. Introduced to replace dangling parent commits where
* a parent commit might be collected.
*
* @param id commit id
* @param commit the commit
*
* @throws Exception if an error occurs
*/
void replaceCommit(Id id, Commit commit) throws Exception;
/**
* Mark a node.
*
* @param id
* node id
* @return {@code true} if the node was not marked before;
* {@code false} otherwise
*
* @throws Exception if an error occurs
*/
boolean markNode(Id id) throws Exception;
/**
* Mark a child node entry map.
*
* @param id
* child node entry map id
* @return {@code true} if the child node entry map was not marked before;
* {@code false} otherwise
*
* @throws Exception if an error occurs
*/
boolean markCNEMap(Id id) throws Exception;
/**
* Sweep all objects that are not marked and were written before the GC started.
*
* @return number of swept items or -1 if number is unknown
* @throws Exception if an error occurs
*/
int sweep() throws Exception;
}