DadanielZ commented on a change in pull request #1694: HADOOP-13327 Output Stream Specification. URL: https://github.com/apache/hadoop/pull/1694#discussion_r352788938
########## File path: hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/impl/StoreImplementationUtils.java ########## @@ -0,0 +1,95 @@ +/* + * 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.impl; + +import java.io.InputStream; +import java.io.OutputStream; + +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.classification.InterfaceStability; +import org.apache.hadoop.fs.StreamCapabilities; + +import static org.apache.hadoop.fs.StreamCapabilities.HFLUSH; +import static org.apache.hadoop.fs.StreamCapabilities.HSYNC; + +/** + * Utility classes to help implementing filesystems and streams. + */ [email protected] [email protected] +public final class StoreImplementationUtils { + + private StoreImplementationUtils() { + } + + /** + * Check the supplied capabilities for being those required for full + * {@code Syncable.hsync()} and {@code Syncable.hflush()} functionality. + * @param capability capability string. + * @return true if either refers to one of the Syncable operations. + */ + public static boolean supportsSyncable(String capability) { + return capability.equalsIgnoreCase(HSYNC) || + capability.equalsIgnoreCase((HFLUSH)); + } + + /** + * Probe for an object having a capability; returns true + * iff the stream implements {@link StreamCapabilities} and its + * {@code hasCapabilities()} method returns true for the capability. + * This is a package private method intended to provided a common + * implementation for input and output streams. + * {@link StreamCapabilities#hasCapability(String)} call is for public use. + * @param object object to probe. + * @param capability capability to probe for + * @return true iff the object implements stream capabilities and + * declares that it supports the capability. + */ + static boolean objectHasCapability(Object object, String capability) { + if (object instanceof StreamCapabilities) { + return ((StreamCapabilities) object).hasCapability(capability); + } + return false; + } + + /** + * Probe for an output stream having a capability; returns true + * iff the stream implements {@link StreamCapabilities} and its + * {@code hasCapabilities()} method returns true for the capability. + * @param out output stream + * @param capability capability to probe for + * @return true iff the stream declares that it supports the capability. + */ + public static boolean hasCapability(OutputStream out, String capability) { + return objectHasCapability(out, capability); + } + + /** + * Probe for an input stream having a capability; returns true + * iff the stream implements {@link StreamCapabilities} and its Review comment: typo ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
