org.factcast.store.pgsql.internal.catchup.PgCatchUpFetchPage.java Source code

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Here is the source code for org.factcast.store.pgsql.internal.catchup.PgCatchUpFetchPage.java

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/*
 * Copyright  2018 Mercateo AG (http://www.mercateo.com)
 *
 * 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.factcast.store.pgsql.internal.catchup;

import java.util.LinkedList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

import org.factcast.core.Fact;
import org.factcast.core.subscription.SubscriptionRequestTO;
import org.factcast.store.pgsql.internal.PgConstants;
import org.factcast.store.pgsql.internal.rowmapper.PgFactExtractor;
import org.factcast.store.pgsql.internal.rowmapper.PgIdFactExtractor;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.PreparedStatementSetter;

import com.google.common.base.Stopwatch;

import lombok.NonNull;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;

@Slf4j
@RequiredArgsConstructor
public class PgCatchUpFetchPage {

    @NonNull
    final JdbcTemplate jdbc;

    final int pageSize;

    @NonNull
    final SubscriptionRequestTO req;

    final long clientId;

    // use LinkedLists so that we can use remove() rather than iteration, in
    // order to release Facts for GC asap.
    public LinkedList<Fact> fetchFacts(@NonNull AtomicLong serial) {
        Stopwatch sw = Stopwatch.createStarted();
        final LinkedList<Fact> list = new LinkedList<>(jdbc.query(PgConstants.SELECT_FACT_FROM_CATCHUP,
                createSetter(serial, pageSize), new PgFactExtractor(serial)));
        sw.stop();
        log.debug("{}  fetched next page of Facts for cid={}, limit={}, ser>{} in {}ms", req, clientId, pageSize,
                serial.get(), sw.elapsed(TimeUnit.MILLISECONDS));
        return list;
    }

    private PreparedStatementSetter createSetter(AtomicLong serial, int pageSize) {
        return ps -> {
            ps.setLong(1, clientId);
            ps.setLong(2, serial.get());
            ps.setLong(3, pageSize);
        };
    }

    // use LinkedLists so that we can use remove() rather than iteration, in
    // order to release Facts for GC asap.
    public LinkedList<Fact> fetchIdFacts(@NonNull AtomicLong serial) {
        Stopwatch sw = Stopwatch.createStarted();
        final LinkedList<Fact> list = new LinkedList<>(jdbc.query(PgConstants.SELECT_ID_FROM_CATCHUP,
                createSetter(serial, pageSize), new PgIdFactExtractor(serial)));
        sw.stop();
        log.debug("{}  fetched next page of Ids for cid={}, limit={}, ser>{} in {}ms", req, clientId, pageSize,
                serial.get(), sw.elapsed(TimeUnit.MILLISECONDS));
        return list;
    }
}