com.hazelcast.cache.impl.journal.CacheEventJournalReadOperation Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.cache.impl.journal;
import com.hazelcast.cache.impl.CacheDataSerializerHook;
import com.hazelcast.cache.impl.CacheService;
import com.hazelcast.cache.EventJournalCacheEvent;
import com.hazelcast.internal.journal.EventJournal;
import com.hazelcast.internal.journal.EventJournalReadOperation;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.ringbuffer.impl.ReadResultSetImpl;
import java.io.IOException;
import java.util.function.Function;
import java.util.function.Predicate;
/**
* Reads from the cache event journal in batches. You may specify the start sequence,
* the minumum required number of items in the response, the maximum number of items
* in the response, a predicate that the events should pass and a projection to
* apply to the events in the journal.
* If the event journal currently contains less events than the required minimum, the
* call will wait until it has sufficient items.
* The predicate, filter and projection may be {@code null} in which case all elements are returned
* and no projection is applied.
*
* @param the return type of the projection. It is equal to the journal event type
* if the projection is {@code null} or it is the identity projection
* @since 3.9
*/
public class CacheEventJournalReadOperation
extends EventJournalReadOperation {
protected Predicate> predicate;
protected Function, ? extends T> projection;
public CacheEventJournalReadOperation() {
}
public CacheEventJournalReadOperation(
String cacheName, long startSequence, int minSize, int maxSize,
Predicate> predicate,
Function, ? extends T> projection
) {
super(cacheName, startSequence, minSize, maxSize);
this.predicate = predicate;
this.projection = projection;
}
@Override
protected EventJournal getJournal() {
final CacheService service = getService();
return service.getEventJournal();
}
@Override
public int getFactoryId() {
return CacheDataSerializerHook.F_ID;
}
@Override
public int getClassId() {
return CacheDataSerializerHook.EVENT_JOURNAL_READ_OPERATION;
}
@Override
public String getServiceName() {
return CacheService.SERVICE_NAME;
}
@Override
protected void writeInternal(ObjectDataOutput out) throws IOException {
super.writeInternal(out);
out.writeObject(predicate);
out.writeObject(projection);
}
@Override
protected void readInternal(ObjectDataInput in) throws IOException {
super.readInternal(in);
predicate = in.readObject();
projection = in.readObject();
}
@Override
protected ReadResultSetImpl createResultSet() {
return new CacheEventJournalReadResultSetImpl(
minSize, maxSize, getNodeEngine().getSerializationService(), predicate, projection);
}
}