nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/status/history/storage/BufferedWriterForStatusStorage.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.nifi.controller.status.history.storage;

import org.apache.commons.lang3.tuple.Pair;

import java.time.Instant;
import java.util.ArrayList;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

public class BufferedWriterForStatusStorage<T> implements BufferedEntryWriter<Pair<Instant, T>> {
    private final BlockingQueue<Pair<Instant, T>> queue = new LinkedBlockingQueue<>();
    private final StatusStorage<T> statusStorage;
    private final int batchSize;

    public BufferedWriterForStatusStorage(final StatusStorage<T> statusStorage, final int batchSize) {
        this.statusStorage = statusStorage;
        this.batchSize = batchSize;
    }

    @Override
    public void collect(final Pair<Instant, T> entryToStore) {
        queue.add(entryToStore);
    }

    @Override
    public void flush() {
        final ArrayList<Pair<Instant, T>> entries = new ArrayList<>(batchSize);
        queue.drainTo(entries, batchSize);

        if (!entries.isEmpty()) {
            statusStorage.store(entries);
        }
    }
}