com.hazelcast.sql.impl.extract.QueryTarget Maven / Gradle / Ivy
/*
* Copyright 2024 Hazelcast Inc.
*
* Licensed under the Hazelcast Community License (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://hazelcast.com/hazelcast-community-license
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.sql.impl.extract;
import com.hazelcast.internal.serialization.Data;
import com.hazelcast.sql.impl.type.QueryDataType;
/**
* Target that is used to extract values from map entry's key or value.
*
* Extractors are created once per query using the {@link #createExtractor(String, QueryDataType)} method. The target is then
* updated for every map record using the {@link #setTarget(Object, Data)} method, while extractors remain the same.
*
* The motivation for this design is to minimize the overhead on extractors creation and to avoid constant overhead associated
* with data extraction, by maintaining the state. An example is {@code PortableGetter} that opens a reader on every get
* operation. Instead, the reader might be opened in {@code setTarget} once and then reused for all fields.
*/
public interface QueryTarget {
void setTarget(Object target, Data targetData);
QueryExtractor createExtractor(String path, QueryDataType type);
}