net.openhft.chronicle.map.replication.MapRemoteQueryContext Maven / Gradle / Ivy

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/*
 * Copyright 2012-2018 Chronicle Map Contributors
 *
 * 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 net.openhft.chronicle.map.replication;

import net.openhft.chronicle.hash.Data;
import net.openhft.chronicle.hash.replication.RemoteOperationContext;
import net.openhft.chronicle.hash.serialization.SizeMarshaller;
import net.openhft.chronicle.map.ChronicleMap;
import net.openhft.chronicle.map.ChronicleMapBuilder;
import net.openhft.chronicle.map.MapEntryOperations;
import net.openhft.chronicle.map.MapQueryContext;
import org.jetbrains.annotations.Nullable;

/**
 * Context of remote {@link ChronicleMap} queries and internal replication operations.
 *
 * @param  the map key type
 * @param  the map value type
 * @param  the return type of {@link MapEntryOperations} specified for the queried map
 * @see MapRemoteOperations
 */
public interface MapRemoteQueryContext extends MapQueryContext,
        RemoteOperationContext {
    @Nullable
    @Override
    MapReplicableEntry entry();

    /**
     * The value used as a tombstone, for removed entries, to save space. This value has {@linkplain
     * SizeMarshaller#minStorableSize()} minimum possible size} for {@linkplain
     * ChronicleMapBuilder#valueSizeMarshaller(SizeMarshaller) the configured value size
     * marshaller}.
     * 
     * The returned value doesn't have object form (i. e. it's {@link Data#get()} and {@link
     * Data#getUsing(Object)} methods throw {@code UnsupportedOperationException}), it has only
     * bytes form, of all zero bytes.
     *
     * @return dummy value of all zeros, of the minimum possible size.
     */
    Data dummyZeroValue();
}