org.apache.hadoop.hive.ql.exec.tez.ObjectCache.java Source code

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Here is the source code for org.apache.hadoop.hive.ql.exec.tez.ObjectCache.java

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/**
 * 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.hadoop.hive.ql.exec.tez;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.tez.runtime.api.ObjectRegistry;

import com.google.common.base.Preconditions;

/**
 * ObjectCache. Tez implementation based on the tez object registry.
 *
 */
public class ObjectCache implements org.apache.hadoop.hive.ql.exec.ObjectCache {

    private static final Log LOG = LogFactory.getLog(ObjectCache.class.getName());

    // ObjectRegistry is available via the Input/Output/ProcessorContext.
    // This is setup as part of the Tez Processor construction, so that it is available whenever an
    // instance of the ObjectCache is created. The assumption is that Tez will initialize the Processor
    // before anything else.
    private volatile static ObjectRegistry staticRegistry;

    private static ExecutorService staticPool;

    private final ObjectRegistry registry;

    public ObjectCache() {
        Preconditions.checkNotNull(staticRegistry,
                "Object registry not setup yet. This should have been setup by the TezProcessor");
        registry = staticRegistry;
    }

    public static void setupObjectRegistry(ObjectRegistry objectRegistry) {
        staticRegistry = objectRegistry;
        staticPool = Executors.newCachedThreadPool();
    }

    @Override
    public void release(String key) {
        // nothing to do
        LOG.info("Releasing key: " + key);
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> T retrieve(String key, Callable<T> fn) throws HiveException {
        T value;
        try {
            value = (T) registry.get(key);
            if (value == null) {
                value = fn.call();
                LOG.info("Caching key: " + key);
                registry.cacheForVertex(key, value);
            } else {
                LOG.info("Found " + key + " in cache with value: " + value);
            }
        } catch (Exception e) {
            throw new HiveException(e);
        }
        return value;
    }

    @Override
    public <T> Future<T> retrieveAsync(final String key, final Callable<T> fn) throws HiveException {
        return staticPool.submit(new Callable<T>() {
            @Override
            public T call() throws Exception {
                return retrieve(key, fn);
            }
        });
    }

    @Override
    public void remove(String key) {
        LOG.info("Removing key: " + key);
        registry.delete(key);
    }
}