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ASF GitHub Bot logged work on HADOOP-17475: ------------------------------------------- Author: ASF GitHub Bot Created on: 01/Feb/21 17:17 Start Date: 01/Feb/21 17:17 Worklog Time Spent: 10m Work Description: steveloughran commented on a change in pull request #2548: URL: https://github.com/apache/hadoop/pull/2548#discussion_r567989510 ########## File path: hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/ITestAbfsListStatusRemoteIterator.java ########## @@ -0,0 +1,338 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.azurebfs; + +import java.io.FileNotFoundException; +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.Callable; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.Future; + +import org.assertj.core.api.Assertions; +import org.junit.Test; +import org.mockito.Mockito; + +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.fs.RemoteIterator; +import org.apache.hadoop.fs.azurebfs.services.AbfsListStatusRemoteIterator; +import org.apache.hadoop.fs.azurebfs.services.ListingSupport; + +import static org.mockito.ArgumentMatchers.any; +import static org.mockito.ArgumentMatchers.anyBoolean; +import static org.mockito.ArgumentMatchers.anyList; +import static org.mockito.ArgumentMatchers.nullable; +import static org.mockito.Mockito.verify; + +/** + * Test ListStatusRemoteIterator operation. + */ +public class ITestAbfsListStatusRemoteIterator extends AbstractAbfsIntegrationTest { + + private static final int TEST_FILES_NUMBER = 1000; + + public ITestAbfsListStatusRemoteIterator() throws Exception { + super(); Review comment: cut ########## File path: hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java ########## @@ -982,6 +985,19 @@ public boolean exists(Path f) throws IOException { return super.exists(f); } + @Override + public RemoteIterator<FileStatus> listStatusIterator(Path path) + throws IOException { + LOG.debug("AzureBlobFileSystem.listStatusIterator path : {}", path); + if (abfsStore.getAbfsConfiguration().enableAbfsListIterator()) { + AbfsListStatusRemoteIterator abfsLsItr = + new AbfsListStatusRemoteIterator(getFileStatus(path), abfsStore); + return RemoteIterators.typeCastingRemoteIterator(abfsLsItr); Review comment: nice ########## File path: hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsListStatusRemoteIterator.java ########## @@ -0,0 +1,159 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.azurebfs.services; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.TimeUnit; +import javax.activation.UnsupportedDataTypeException; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.RemoteIterator; + +public class AbfsListStatusRemoteIterator + implements RemoteIterator<FileStatus> { + + private static final Logger LOG = LoggerFactory + .getLogger(AbfsListStatusRemoteIterator.class); + + private static final boolean FETCH_ALL_FALSE = false; + private static final int MAX_QUEUE_SIZE = 10; + private static final long POLL_WAIT_TIME_IN_MS = 250; + + private final FileStatus fileStatus; + private final ListingSupport listingSupport; + private final ArrayBlockingQueue<Object> iteratorsQueue; + + private volatile boolean isAsyncInProgress = false; + private boolean isIterationComplete = false; + private String continuation; + private Iterator<FileStatus> currIterator; + + public AbfsListStatusRemoteIterator(final FileStatus fileStatus, + final ListingSupport listingSupport) { + this.fileStatus = fileStatus; + this.listingSupport = listingSupport; + iteratorsQueue = new ArrayBlockingQueue<>(MAX_QUEUE_SIZE); + currIterator = Collections.emptyIterator(); + fetchBatchesAsync(); + } + + @Override + public boolean hasNext() throws IOException { + if (currIterator.hasNext()) { + return true; + } + currIterator = getNextIterator(); + return currIterator.hasNext(); + } + + @Override + public FileStatus next() throws IOException { + if (!this.hasNext()) { + throw new NoSuchElementException(); + } + return currIterator.next(); + } + + private Iterator<FileStatus> getNextIterator() throws IOException { + fetchBatchesAsync(); + try { + Object obj = null; + while (obj == null + && (!isIterationComplete || !iteratorsQueue.isEmpty())) { + obj = iteratorsQueue.poll(POLL_WAIT_TIME_IN_MS, TimeUnit.MILLISECONDS); + } + if (obj == null) { + return Collections.emptyIterator(); + } else if (obj instanceof Iterator) { + return (Iterator<FileStatus>) obj; + } else if (obj instanceof IOException) { + throw (IOException) obj; + } else { + throw new UnsupportedDataTypeException(); + } + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + LOG.error("Thread got interrupted: {}", e); + throw new IOException(e); + } + } + + private void fetchBatchesAsync() { + if (isAsyncInProgress || isIterationComplete) { + return; + } + synchronized (this) { + if (isAsyncInProgress || isIterationComplete) { + return; + } + isAsyncInProgress = true; + } + CompletableFuture.runAsync(() -> asyncOp()); + } + + private void asyncOp() { + try { + while (!isIterationComplete && iteratorsQueue.size() <= MAX_QUEUE_SIZE) { + addNextBatchIteratorToQueue(); + } + } catch (IOException ioe) { + LOG.error("Fetching filestatuses failed", ioe); + try { + iteratorsQueue.put(ioe); + } catch (InterruptedException interruptedException) { + Thread.currentThread().interrupt(); + LOG.error("Thread got interrupted: {}", interruptedException); + } + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + LOG.error("Thread got interrupted: {}", e); + } finally { + synchronized (this) { + isAsyncInProgress = false; + } + } + } + + private void addNextBatchIteratorToQueue() + throws IOException, InterruptedException { + List<FileStatus> fileStatuses = new ArrayList<>(); + continuation = listingSupport + .listStatus(fileStatus.getPath(), null, fileStatuses, FETCH_ALL_FALSE, + continuation); + if(!fileStatuses.isEmpty()) { Review comment: nit: space after `if` ########## File path: hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/AzureBlobFileSystem.java ########## @@ -982,6 +985,19 @@ public boolean exists(Path f) throws IOException { return super.exists(f); } + @Override + public RemoteIterator<FileStatus> listStatusIterator(Path path) + throws IOException { + LOG.debug("AzureBlobFileSystem.listStatusIterator path : {}", path); + if (abfsStore.getAbfsConfiguration().enableAbfsListIterator()) { Review comment: OK, but it's something to plan to cut after a release has been out. So file a new JIRA about cutting the old one. ########## File path: hadoop-tools/hadoop-azure/src/test/java/org/apache/hadoop/fs/azurebfs/ITestAbfsListStatusRemoteIterator.java ########## @@ -0,0 +1,338 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.azurebfs; + +import java.io.FileNotFoundException; +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.Callable; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.Future; + +import org.assertj.core.api.Assertions; +import org.junit.Test; +import org.mockito.Mockito; + +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.fs.RemoteIterator; +import org.apache.hadoop.fs.azurebfs.services.AbfsListStatusRemoteIterator; +import org.apache.hadoop.fs.azurebfs.services.ListingSupport; + +import static org.mockito.ArgumentMatchers.any; +import static org.mockito.ArgumentMatchers.anyBoolean; +import static org.mockito.ArgumentMatchers.anyList; +import static org.mockito.ArgumentMatchers.nullable; +import static org.mockito.Mockito.verify; + +/** + * Test ListStatusRemoteIterator operation. + */ +public class ITestAbfsListStatusRemoteIterator extends AbstractAbfsIntegrationTest { + + private static final int TEST_FILES_NUMBER = 1000; + + public ITestAbfsListStatusRemoteIterator() throws Exception { + super(); + } + + @Test + public void testAbfsIteratorWithHasNext() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + final List<String> fileNames = createFilesUnderDirectory(TEST_FILES_NUMBER, + testDir, "testListPath"); + + ListingSupport listngSupport = Mockito.spy(getFileSystem().getAbfsStore()); + RemoteIterator<FileStatus> fsItr = new AbfsListStatusRemoteIterator( + getFileSystem().getFileStatus(testDir), listngSupport); + Assertions.assertThat(fsItr) + .describedAs("RemoteIterator should be instance of " + + "AbfsListStatusRemoteIterator by default") + .isInstanceOf(AbfsListStatusRemoteIterator.class); + int itrCount = 0; + while (fsItr.hasNext()) { + FileStatus fileStatus = fsItr.next(); + String pathStr = fileStatus.getPath().toString(); + fileNames.remove(pathStr); + itrCount++; + } + Assertions.assertThat(itrCount) + .describedAs("Number of iterations should be equal to the files " + + "created") + .isEqualTo(TEST_FILES_NUMBER); + Assertions.assertThat(fileNames.size()) + .describedAs("After removing every iterm found from the iterator, " + + "there should be no more elements in the fileNames") + .isEqualTo(0); + int minNumberOfInvokations = TEST_FILES_NUMBER / 10; + verify(listngSupport, Mockito.atLeast(minNumberOfInvokations)) + .listStatus(any(Path.class), nullable(String.class), + anyList(), anyBoolean(), + nullable(String.class)); + } + + @Test + public void testAbfsIteratorWithoutHasNext() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + final List<String> fileNames = createFilesUnderDirectory(TEST_FILES_NUMBER, + testDir, "testListPath"); + + ListingSupport listngSupport = Mockito.spy(getFileSystem().getAbfsStore()); + RemoteIterator<FileStatus> fsItr = new AbfsListStatusRemoteIterator( + getFileSystem().getFileStatus(testDir), listngSupport); + Assertions.assertThat(fsItr) + .describedAs("RemoteIterator should be instance of " + + "AbfsListStatusRemoteIterator by default") + .isInstanceOf(AbfsListStatusRemoteIterator.class); + int itrCount = 0; + for (int i = 0; i < TEST_FILES_NUMBER; i++) { + FileStatus fileStatus = fsItr.next(); + String pathStr = fileStatus.getPath().toString(); + fileNames.remove(pathStr); + itrCount++; + } + Assertions.assertThatThrownBy(() -> fsItr.next()) + .describedAs( + "next() should throw NoSuchElementException since next has been " + + "called " + TEST_FILES_NUMBER + " times") + .isInstanceOf(NoSuchElementException.class); + Assertions.assertThat(itrCount) + .describedAs("Number of iterations should be equal to the files " + + "created") + .isEqualTo(TEST_FILES_NUMBER); + Assertions.assertThat(fileNames.size()) + .describedAs("After removing every iterm found from the iterator, " + + "there should be no more elements in the fileNames") + .isEqualTo(0); + int minNumberOfInvokations = TEST_FILES_NUMBER / 10; + verify(listngSupport, Mockito.atLeast(minNumberOfInvokations)) + .listStatus(any(Path.class), nullable(String.class), + anyList(), anyBoolean(), + nullable(String.class)); + } + + @Test + public void testWithAbfsIteratorDisabled() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + setEnableAbfsIterator(false); + final List<String> fileNames = createFilesUnderDirectory(TEST_FILES_NUMBER, + testDir, "testListPath"); + + RemoteIterator<FileStatus> fsItr = + getFileSystem().listStatusIterator(testDir); + Assertions.assertThat(fsItr) + .describedAs("RemoteIterator should not be instance of " + + "AbfsListStatusRemoteIterator when it is disabled") + .isNotInstanceOf(AbfsListStatusRemoteIterator.class); + int itrCount = 0; + while (fsItr.hasNext()) { + FileStatus fileStatus = fsItr.next(); + String pathStr = fileStatus.getPath().toString(); + fileNames.remove(pathStr); + itrCount++; + } + Assertions.assertThat(itrCount) + .describedAs("Number of iterations should be equal to the files " + + "created") + .isEqualTo(TEST_FILES_NUMBER); + Assertions.assertThat(fileNames.size()) + .describedAs("After removing every iterm found from the iterator, " + + "there should be no more elements in the fileNames") + .isEqualTo(0); + } + + @Test + public void testWithAbfsIteratorDisabledWithoutHasNext() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + setEnableAbfsIterator(false); + final List<String> fileNames = createFilesUnderDirectory(TEST_FILES_NUMBER, + testDir, "testListPath"); + + RemoteIterator<FileStatus> fsItr = + getFileSystem().listStatusIterator(testDir); + Assertions.assertThat(fsItr) + .describedAs("RemoteIterator should not be instance of " + + "AbfsListStatusRemoteIterator when it is disabled") + .isNotInstanceOf(AbfsListStatusRemoteIterator.class); + int itrCount = 0; + for (int i = 0; i < TEST_FILES_NUMBER; i++) { + FileStatus fileStatus = fsItr.next(); + String pathStr = fileStatus.getPath().toString(); + fileNames.remove(pathStr); + itrCount++; + } + Assertions.assertThatThrownBy(() -> fsItr.next()) + .describedAs( + "next() should throw NoSuchElementException since next has been " + + "called " + TEST_FILES_NUMBER + " times") + .isInstanceOf(NoSuchElementException.class); + Assertions.assertThat(itrCount) + .describedAs("Number of iterations should be equal to the files " + + "created") + .isEqualTo(TEST_FILES_NUMBER); + Assertions.assertThat(fileNames.size()) + .describedAs("After removing every iterm found from the iterator, " + + "there should be no more elements in the fileNames") + .isEqualTo(0); + } + + @Test + public void testNextWhenNoMoreElementsPresent() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + RemoteIterator fsItr = + new AbfsListStatusRemoteIterator(getFileSystem().getFileStatus(testDir), + getFileSystem().getAbfsStore()); + fsItr = Mockito.spy(fsItr); + Mockito.doReturn(false).when(fsItr).hasNext(); + + RemoteIterator<FileStatus> finalFsItr = fsItr; + Assertions.assertThatThrownBy(() -> finalFsItr.next()) + .describedAs( + "next() should throw NoSuchElementException if hasNext() return " + + "false") + .isInstanceOf(NoSuchElementException.class); + } + + @Test + public void testHasNextForEmptyDir() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + RemoteIterator<FileStatus> fsItr = getFileSystem() + .listStatusIterator(testDir); + Assertions.assertThat(fsItr.hasNext()) + .describedAs("hasNext returns false for empty directory") + .isFalse(); + } + + @Test + public void testHasNextForFile() throws Exception { + final AzureBlobFileSystem fs = getFileSystem(); + String testFileName = "testFile"; + Path testFile = new Path(testFileName); + getFileSystem().create(testFile); + setPageSize(10); + RemoteIterator<FileStatus> fsItr = fs.listStatusIterator(testFile); + Assertions.assertThat(fsItr.hasNext()) + .describedAs("hasNext returns true for file").isTrue(); + Assertions.assertThat(fsItr.next().getPath().toString()) + .describedAs("next returns the file itself") + .endsWith(testFileName); + } + + @Test + public void testIOException() throws Exception { + Path testDir = createTestDirectory(); + setPageSize(10); + getFileSystem().mkdirs(testDir); + + String exceptionMessage = "test exception"; + ListingSupport lsSupport =getMockListingSupport(exceptionMessage); + RemoteIterator fsItr = + new AbfsListStatusRemoteIterator(getFileSystem().getFileStatus(testDir), + lsSupport); + + Assertions.assertThatThrownBy(() -> fsItr.next()) + .describedAs( + "When ioException is not null and queue is empty exception should be " + + "thrown") + .isInstanceOf(IOException.class) + .hasMessage(exceptionMessage); + } + + @Test + public void testNonExistingPath() throws Throwable { + Path nonExistingDir = new Path("nonExistingPath"); + Assertions.assertThatThrownBy( + () -> getFileSystem().listStatusIterator(nonExistingDir)).describedAs( + "test the listStatusIterator call on a path which is not " + + "present should result in FileNotFoundException") + .isInstanceOf(FileNotFoundException.class); + } + + private ListingSupport getMockListingSupport(String exceptionMessage) { + return new ListingSupport() { + @Override + public FileStatus[] listStatus(Path path) throws IOException { + return null; + } + + @Override + public FileStatus[] listStatus(Path path, String startFrom) + throws IOException { + return null; + } + + @Override + public String listStatus(Path path, String startFrom, + List<FileStatus> fileStatuses, boolean fetchAll, String continuation) + throws IOException { + throw new IOException(exceptionMessage); + } + }; + } + + private Path createTestDirectory() throws IOException { + String testDirectoryName = "testDirectory" + System.currentTimeMillis(); + Path testDirectory = new Path(testDirectoryName); + getFileSystem().mkdirs(testDirectory); + return testDirectory; + } + + private void setEnableAbfsIterator(boolean shouldEnable) throws IOException { + AzureBlobFileSystemStore abfsStore = getAbfsStore(getFileSystem()); + abfsStore.getAbfsConfiguration().setEnableAbfsListIterator(shouldEnable); + } + + private void setPageSize(int pageSize) throws IOException { + AzureBlobFileSystemStore abfsStore = getAbfsStore(getFileSystem()); + abfsStore.getAbfsConfiguration().setListMaxResults(pageSize); + } + + private List<String> createFilesUnderDirectory(int numFiles, Path rootPath, + String filenamePrefix) + throws ExecutionException, InterruptedException, IOException { + final List<Future<Void>> tasks = new ArrayList<>(); + final List<String> fileNames = new ArrayList<>(); + ExecutorService es = Executors.newFixedThreadPool(10); + for (int i = 0; i < numFiles; i++) { + final Path filePath = new Path(rootPath, filenamePrefix + i); + Callable<Void> callable = () -> { + getFileSystem().create(filePath); + fileNames.add(makeQualified(filePath).toString()); + return null; + }; + tasks.add(es.submit(callable)); + } + for (Future<Void> task : tasks) { + task.get(); + } + es.shutdownNow(); Review comment: this should be in a finally block ########## File path: hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsListStatusRemoteIterator.java ########## @@ -0,0 +1,159 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.azurebfs.services; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.TimeUnit; +import javax.activation.UnsupportedDataTypeException; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.RemoteIterator; + +public class AbfsListStatusRemoteIterator + implements RemoteIterator<FileStatus> { + + private static final Logger LOG = LoggerFactory + .getLogger(AbfsListStatusRemoteIterator.class); + + private static final boolean FETCH_ALL_FALSE = false; + private static final int MAX_QUEUE_SIZE = 10; + private static final long POLL_WAIT_TIME_IN_MS = 250; + + private final FileStatus fileStatus; + private final ListingSupport listingSupport; + private final ArrayBlockingQueue<Object> iteratorsQueue; + + private volatile boolean isAsyncInProgress = false; + private boolean isIterationComplete = false; + private String continuation; + private Iterator<FileStatus> currIterator; + + public AbfsListStatusRemoteIterator(final FileStatus fileStatus, + final ListingSupport listingSupport) { + this.fileStatus = fileStatus; + this.listingSupport = listingSupport; + iteratorsQueue = new ArrayBlockingQueue<>(MAX_QUEUE_SIZE); + currIterator = Collections.emptyIterator(); + fetchBatchesAsync(); + } + + @Override + public boolean hasNext() throws IOException { + if (currIterator.hasNext()) { + return true; + } + currIterator = getNextIterator(); + return currIterator.hasNext(); + } + + @Override + public FileStatus next() throws IOException { + if (!this.hasNext()) { + throw new NoSuchElementException(); + } + return currIterator.next(); + } + + private Iterator<FileStatus> getNextIterator() throws IOException { + fetchBatchesAsync(); + try { + Object obj = null; + while (obj == null + && (!isIterationComplete || !iteratorsQueue.isEmpty())) { + obj = iteratorsQueue.poll(POLL_WAIT_TIME_IN_MS, TimeUnit.MILLISECONDS); + } + if (obj == null) { + return Collections.emptyIterator(); + } else if (obj instanceof Iterator) { Review comment: I can't help thinking this a bit of an abuse of a queue to mix object types in there -but to do it in any other way within java would be pretty convoluted (new class, essentially), so let's go with what is here. Just need to make sure there's test coverage for the IOE path ########## File path: hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/ListingSupport.java ########## @@ -0,0 +1,75 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.azurebfs.services; + +import java.io.IOException; +import java.util.List; + +import org.apache.hadoop.classification.InterfaceStability; +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.Path; + +public interface ListingSupport { + + /** + * @param path The list path. + * @return the entries in the path. + */ + FileStatus[] listStatus(Path path) throws IOException; + + /** + * @param path Path the list path. + * @param startFrom The entry name that list results should start with. + * For example, if folder "/folder" contains four + * files: "afile", "bfile", "hfile", "ifile". Then + * listStatus(Path("/folder"), "hfile") will return + * "/folder/hfile" and "folder/ifile" Notice that if + * startFrom is a non-existent entry name, then the + * list response contains all entries after this + * non-existent entry in lexical order: listStatus + * (Path("/folder"), "cfile") will return + * "/folder/hfile" and "/folder/ifile". + * @return the entries in the path start from "startFrom" in lexical order. + */ + @InterfaceStability.Unstable Review comment: add that at the actual interface, along with the @Private . Not that we'd expect anyone to use it ---------------------------------------------------------------- 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 Issue Time Tracking ------------------- Worklog Id: (was: 545456) Time Spent: 4h 50m (was: 4h 40m) > Implement listStatusIterator > ---------------------------- > > Key: HADOOP-17475 > URL: https://issues.apache.org/jira/browse/HADOOP-17475 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/azure > Affects Versions: 3.4.0 > Reporter: Bilahari T H > Priority: Major > Labels: pull-request-available > Time Spent: 4h 50m > Remaining Estimate: 0h > -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org