org.apache.hadoop.hive.serde2.avro.InstanceCache Maven / Gradle / Ivy

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/*
 * 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.apache.hadoop.hive.serde2.avro;

import com.facebook.presto.hive.$internal.com.google.common.cache.Cache;
import com.facebook.presto.hive.$internal.com.google.common.cache.CacheBuilder;

import java.util.Set;
import java.util.concurrent.TimeUnit;

/**
 * This is a thread-safe, time-bounded fork of the Hive version.
 * It also includes the correctness fix from HIVE-11288.
 */
public abstract class InstanceCache
{
    private final Cache cache = CacheBuilder.newBuilder()
            .expireAfterWrite(1, TimeUnit.MINUTES)
            .build();

    protected InstanceCache() {}

    public V retrieve(K hv)
            throws AvroSerdeException
    {
        return retrieve(hv, null);
    }

    public V retrieve(K hv, Set seenSchemas)
            throws AvroSerdeException
    {
        V instance = cache.getIfPresent(hv);

        if (instance == null) {
            instance = makeInstance(hv, seenSchemas);
            cache.put(hv, instance);
        }

        return instance;
    }

    protected abstract V makeInstance(K hv, Set seenSchemas)
            throws AvroSerdeException;
}