org.modeshape.jcr.journal.ChangeJournal Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
*
* Licensed 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.modeshape.jcr.journal;
import java.util.Collections;
import java.util.Iterator;
import org.joda.time.DateTime;
import org.modeshape.jcr.cache.change.ChangeSetListener;
/**
* An entity which records all changes which occur in a repository via {@code ChangeSet} instances.
*
* @author Horia Chiorean ([email protected])
*/
public interface ChangeJournal extends ChangeSetListener {
/**
* Starts this journal instance.
*
* @throws Exception if anything fails during start
*/
public void start() throws Exception;
/**
* Stops the journal.
*/
public void shutdown();
/**
* Removes older entries. Each journal is free to decide the semantics behind "old".
*/
public void removeOldRecords();
/**
* Returns all the records this journal holds
*
* @param descendingOrder flag which indicates whether the entries
* @return a {@link Records} instance
*/
public Records allRecords( boolean descendingOrder );
/**
* Returns the last record from the journal.
*
* @return either a {@link org.modeshape.jcr.journal.JournalRecord} instance or {@code null} if the journal is empty.
*/
public JournalRecord lastRecord();
/**
* Returns all records that have changesets which are newer than a given timestamp.
*
* @param changeSetTime the {@link org.joda.time.DateTime} of the changes representing the lower bound; may be null indicating
* that *all the records* should be returned.
* @param inclusive flag indicating whether the timestamp should be used inclusively or exclusively
* @param descendingOrder flag indicating if the records should be returned in ascending order (oldest to newest) or
* descending order (newest to oldest)
* @return a {@link Records} instance; never {@code null}
*/
public Records recordsNewerThan( DateTime changeSetTime,
boolean inclusive,
boolean descendingOrder );
/**
* Adds one or more journal records to a journal.
*
* @param records a {@link JournalRecord} array.
*/
public void addRecords( JournalRecord... records );
/**
* Returns the id of this change journal.
*
* @return a {@link String}, never {@code null}
*/
public String journalId();
/**
* An {@link Iterable} extension which provides information about the number of entries the underlying collection holds.
*/
public interface Records extends Iterable {
public static final Records EMPTY = new Records() {
@Override
public int size() {
return 0;
}
@Override
public Iterator iterator() {
return Collections.emptySet().iterator();
}
@Override
public boolean isEmpty() {
return true;
}
};
/**
* Returns the number of records.
*
* @return an int
*/
public int size();
/**
* Returns true if the records set is empty.
*
* @return {@code true} if there aren't any records.
*/
public boolean isEmpty();
}
}
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