org.apache.beam.runners.dataflow.util.CloudObjects.java Source code

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Here is the source code for org.apache.beam.runners.dataflow.util.CloudObjects.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.beam.runners.dataflow.util;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.collect.ImmutableMap;
import java.util.Map;
import java.util.ServiceLoader;
import org.apache.beam.sdk.coders.Coder;
import org.apache.beam.sdk.coders.CustomCoder;

/** Utilities for converting an object to a {@link CloudObject}. */
public class CloudObjects {
    private CloudObjects() {
    }

    static final Map<Class<? extends Coder>, CloudObjectTranslator<? extends Coder>> CODER_TRANSLATORS = populateCoderTranslators();
    static final Map<String, CloudObjectTranslator<? extends Coder>> CLOUD_OBJECT_CLASS_NAME_TRANSLATORS = populateCloudObjectTranslators();

    private static Map<Class<? extends Coder>, CloudObjectTranslator<? extends Coder>> populateCoderTranslators() {
        ImmutableMap.Builder<Class<? extends Coder>, CloudObjectTranslator<? extends Coder>> builder = ImmutableMap
                .builder();
        for (CoderCloudObjectTranslatorRegistrar coderRegistrar : ServiceLoader
                .load(CoderCloudObjectTranslatorRegistrar.class)) {
            builder.putAll(coderRegistrar.classesToTranslators());
        }
        return builder.build();
    }

    private static Map<String, CloudObjectTranslator<? extends Coder>> populateCloudObjectTranslators() {
        ImmutableMap.Builder<String, CloudObjectTranslator<? extends Coder>> builder = ImmutableMap.builder();
        for (CoderCloudObjectTranslatorRegistrar coderRegistrar : ServiceLoader
                .load(CoderCloudObjectTranslatorRegistrar.class)) {
            builder.putAll(coderRegistrar.classNamesToTranslators());
        }
        return builder.build();
    }

    /**
     * Convert the provided {@link Coder} into a {@link CloudObject}.
     */
    public static CloudObject asCloudObject(Coder<?> coder) {
        CloudObjectTranslator<Coder> translator = (CloudObjectTranslator<Coder>) CODER_TRANSLATORS
                .get(coder.getClass());
        if (translator != null) {
            return translator.toCloudObject(coder);
        } else {
            CloudObjectTranslator customCoderTranslator = CODER_TRANSLATORS.get(CustomCoder.class);
            checkNotNull(customCoderTranslator, "No %s registered for %s, but it is in the %s",
                    CloudObjectTranslator.class.getSimpleName(), CustomCoder.class.getSimpleName(),
                    DefaultCoderCloudObjectTranslatorRegistrar.class.getSimpleName());
            return customCoderTranslator.toCloudObject(coder);
        }
    }

    public static Coder<?> coderFromCloudObject(CloudObject cloudObject) {
        CloudObjectTranslator<? extends Coder> translator = CLOUD_OBJECT_CLASS_NAME_TRANSLATORS
                .get(cloudObject.getClassName());
        checkArgument(translator != null, "Unknown %s class %s", Coder.class.getSimpleName(),
                cloudObject.getClassName());
        return translator.fromCloudObject(cloudObject);
    }
}