org.apache.aurora.scheduler.http.TransformationUtils.java Source code

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Here is the source code for org.apache.aurora.scheduler.http.TransformationUtils.java

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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.aurora.scheduler.http;

import java.util.Collection;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;
import com.google.common.collect.Range;

import org.apache.aurora.scheduler.base.Numbers;
import org.apache.aurora.scheduler.storage.entities.IMetadata;
import org.apache.aurora.scheduler.storage.entities.ITaskConfig;

/**
 * Utility class to hold common object to string transformation helper functions.
 */
final class TransformationUtils {
    public static final Function<IMetadata, String> METADATA_TOSTRING = new com.twitter.common.base.Function<IMetadata, String>() {
        @Override
        public String apply(IMetadata item) {
            return item.getKey() + ": " + item.getValue();
        }
    };

    public static final Function<Range<Integer>, String> RANGE_TOSTRING = new Function<Range<Integer>, String>() {
        @Override
        public String apply(Range<Integer> range) {
            int lower = range.lowerEndpoint();
            int upper = range.upperEndpoint();
            return lower == upper ? String.valueOf(lower) : lower + " - " + upper;
        }
    };

    public static final Function<Collection<Integer>, String> INSTANCES_TOSTRING = new Function<Collection<Integer>, String>() {
        @Override
        public String apply(Collection<Integer> instances) {
            return Joiner.on(", ").join(Iterables.transform(Numbers.toRanges(instances), RANGE_TOSTRING));
        }
    };

    private TransformationUtils() {
        // Utility class
    }

    /**
     * Gets an optional task metadata.
     *
     * @param task Task to get metadata from.
     * @return Present if task metadata exists, absent otherwise.
     */
    public static Optional<String> getMetadata(ITaskConfig task) {
        if (task.isSetMetadata()) {
            Iterable<String> metadata = ImmutableSet
                    .copyOf(Iterables.transform(task.getMetadata(), TransformationUtils.METADATA_TOSTRING));
            return Optional.of(Joiner.on(", ").join(Ordering.natural().sortedCopy(metadata)));
        }
        return Optional.absent();
    }
}