mehakmeet commented on a change in pull request #2069: URL: https://github.com/apache/hadoop/pull/2069#discussion_r466152709
########## File path: hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/statistics/impl/IOStatisticsBinding.java ########## @@ -0,0 +1,300 @@ +/* + * 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.fs.statistics.impl; + +import java.io.Serializable; +import java.util.Iterator; +import java.util.Map; +import java.util.TreeMap; +import java.util.concurrent.atomic.AtomicLong; +import java.util.function.BiFunction; +import java.util.function.Function; + +import com.google.common.annotations.VisibleForTesting; + +import org.apache.hadoop.fs.StorageStatistics; +import org.apache.hadoop.fs.statistics.IOStatistics; +import org.apache.hadoop.fs.statistics.IOStatisticsSource; +import org.apache.hadoop.fs.statistics.MeanStatistic; + +/** + * Support for implementing IOStatistics interfaces. + */ +public final class IOStatisticsBinding { + + /** Pattern used for each entry. */ + public static final String ENTRY_PATTERN = "(%s=%s)"; + + /** String to return when a source is null. */ + @VisibleForTesting + public static final String NULL_SOURCE = "()"; + + private IOStatisticsBinding() { + } + + /** + * Create IOStatistics from a storage statistics instance. + * This will be updated as the storage statistics change. + * @param storageStatistics source data. + * @return an IO statistics source. + */ + public static IOStatistics fromStorageStatistics( + StorageStatistics storageStatistics) { + DynamicIOStatisticsBuilder builder = dynamicIOStatistics(); + Iterator<StorageStatistics.LongStatistic> it = storageStatistics + .getLongStatistics(); + while (it.hasNext()) { + StorageStatistics.LongStatistic next = it.next(); + builder.withLongFunctionCounter(next.getName(), + k -> storageStatistics.getLong(k)); + } + return builder.build(); + } + + /** + * Create a builder for dynamic IO Statistics. + * @return a builder to be completed. + */ + public static DynamicIOStatisticsBuilder dynamicIOStatistics() { + return new DynamicIOStatisticsBuilder(); + } + + /** + * Get the shared instance of the immutable empty statistics + * object. + * @return an empty statistics object. + */ + public static IOStatistics emptyStatistics() { + return EmptyIOStatistics.getInstance(); + } + + /** + * Take an IOStatistics instance and wrap it in a source. + * @param statistics statistics. + * @return a source which will return the values + */ + public static IOStatisticsSource wrap(IOStatistics statistics) { + return new SourceWrappedStatistics(statistics); + } + + /** + * Create an a builder for an {@link IOStatisticsStore}. + * + * @return a builder instance. + */ + public static IOStatisticsStoreBuilder iostatisticsStore() { + return new IOStatisticsStoreBuilderImpl(); + } + + /** + * Convert an entry to the string format used in logging. + * + * @param entry entry to evaluate + * @param <E> entry type + * @return formatted string + */ + public static <E> String entryToString( + final Map.Entry<String, E> entry) { + return entryToString(entry.getKey(), entry.getValue()); + } + + /** + * Convert entry values to the string format used in logging. + * + * @param name statistic name + * @param value stat value + * @return formatted string + */ + public static <E> String entryToString( + final String name, final E value) { + return String.format( + ENTRY_PATTERN, + name, + value); + } + + /** + * Copy into the dest map all the source entries. + * The destination is cleared first. + * @param <E> entry type + * @param dest destination of the copy + * @param source source + * @param copyFn function to copy entries + * @return the destination. + */ + public static <E> Map<String, E> copyMap( Review comment: can make this method private. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
