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HADOOP-6900. Make the iterator returned by FileSystem#listLocatedStatus to throw IOException rather than RuntimeException when there is an IO error fetching the next file. Contributed by Hairong Kuang. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@984301 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Hairong Kuang 2010-08-11 04:43:26 +00:00
parent ccbdfba7d1
commit dc2a3d1ca3
11 changed files with 149 additions and 173 deletions
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6
CHANGES.txt
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@ -111,7 +111,11 @@ Trunk (unreleased changes)
HADOOP-6862. Adds api to add/remove user and group to AccessControlList
(amareshwari)
HADOOP6911. doc update for DelegationTokenFetcher (boryas)
HADOOP-6911. doc update for DelegationTokenFetcher (boryas)
HADOOP-6900. Make the iterator returned by FileSystem#listLocatedStatus to
throw IOException rather than RuntimeException when there is an IO error
fetching the next file. (hairong)
OPTIMIZATIONS

52
src/java/org/apache/hadoop/fs/AbstractFileSystem.java
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@ -619,7 +619,7 @@ public abstract class AbstractFileSystem {
}
// Delete the destination that is a file or an empty directory
if (dstStatus.isDirectory()) {
Iterator<FileStatus> list = listStatusIterator(dst);
RemoteIterator<FileStatus> list = listStatusIterator(dst);
if (list != null && list.hasNext()) {
throw new IOException(
"Rename cannot overwrite non empty destination directory " + dst);
@ -757,10 +757,10 @@ public abstract class AbstractFileSystem {
* {@link FileContext#listStatus(Path)} except that Path f must be for this
* file system.
*/
protected Iterator<FileStatus> listStatusIterator(final Path f)
protected RemoteIterator<FileStatus> listStatusIterator(final Path f)
throws AccessControlException, FileNotFoundException,
UnresolvedLinkException, IOException {
return new Iterator<FileStatus>() {
return new RemoteIterator<FileStatus>() {
private int i = 0;
private FileStatus[] statusList = listStatus(f);
@ -776,11 +776,6 @@ public abstract class AbstractFileSystem {
}
return statusList[i++];
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
}
};
}
@ -789,52 +784,29 @@ public abstract class AbstractFileSystem {
* {@link FileContext#listLocatedStatus(Path)} except that Path f
* must be for this file system.
*/
protected Iterator<LocatedFileStatus> listLocatedStatus(final Path f)
protected RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path f)
throws AccessControlException, FileNotFoundException,
UnresolvedLinkException, IOException {
return new Iterator<LocatedFileStatus>() {
private Iterator<FileStatus> itor = listStatusIterator(f);
return new RemoteIterator<LocatedFileStatus>() {
private RemoteIterator<FileStatus> itor = listStatusIterator(f);
/**
* {@inheritDoc}
* @return {@inheritDog}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
*/
@Override
public boolean hasNext() {
public boolean hasNext() throws IOException {
return itor.hasNext();
}
/**
* {@inheritDoc}
* @return {@inheritDoc}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
* @exception {@inheritDoc}
*/
@Override
public LocatedFileStatus next() {
public LocatedFileStatus next() throws IOException {
if (!hasNext()) {
throw new NoSuchElementException("No more entry in " + f);
}
FileStatus result = itor.next();
try {
BlockLocation[] locs = null;
if (result.isFile()) {
locs = getFileBlockLocations(
BlockLocation[] locs = null;
if (result.isFile()) {
locs = getFileBlockLocations(
result.getPath(), 0, result.getLen());
}
return new LocatedFileStatus(result, locs);
} catch (IOException ioe) {
throw (RuntimeException)new RuntimeException().initCause(ioe);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
return new LocatedFileStatus(result, locs);
}
};
}

2
src/java/org/apache/hadoop/fs/ChecksumFileSystem.java
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@ -504,7 +504,7 @@ public abstract class ChecksumFileSystem extends FilterFileSystem {
* @throws IOException
*/
@Override
public Iterator<LocatedFileStatus> listLocatedStatus(Path f)
public RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
throws IOException {
return fs.listLocatedStatus(f, DEFAULT_FILTER);
}

108
src/java/org/apache/hadoop/fs/FileContext.java
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@ -27,10 +27,8 @@ import java.util.Arrays;
import java.util.EnumSet;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.Stack;
import java.util.TreeSet;
@ -1275,12 +1273,13 @@ public final class FileContext {
* @throws UnexpectedServerException If server implementation throws
* undeclared exception to RPC server
*/
public Iterator<FileStatus> listStatus(final Path f) throws
public RemoteIterator<FileStatus> listStatus(final Path f) throws
AccessControlException, FileNotFoundException,
UnsupportedFileSystemException, IOException {
final Path absF = fixRelativePart(f);
return new FSLinkResolver<Iterator<FileStatus>>() {
public Iterator<FileStatus> next(final AbstractFileSystem fs, final Path p)
return new FSLinkResolver<RemoteIterator<FileStatus>>() {
public RemoteIterator<FileStatus> next(
final AbstractFileSystem fs, final Path p)
throws IOException, UnresolvedLinkException {
return fs.listStatusIterator(p);
}
@ -1314,12 +1313,13 @@ public final class FileContext {
* @throws UnexpectedServerException If server implementation throws
* undeclared exception to RPC server
*/
public Iterator<LocatedFileStatus> listLocatedStatus(final Path f) throws
public RemoteIterator<LocatedFileStatus> listLocatedStatus(
final Path f) throws
AccessControlException, FileNotFoundException,
UnsupportedFileSystemException, IOException {
final Path absF = fixRelativePart(f);
return new FSLinkResolver<Iterator<LocatedFileStatus>>() {
public Iterator<LocatedFileStatus> next(
return new FSLinkResolver<RemoteIterator<LocatedFileStatus>>() {
public RemoteIterator<LocatedFileStatus> next(
final AbstractFileSystem fs, final Path p)
throws IOException, UnresolvedLinkException {
return fs.listLocatedStatus(p);
@ -1466,7 +1466,8 @@ public final class FileContext {
return new ContentSummary(status.getLen(), 1, 0);
}
long[] summary = {0, 0, 1};
Iterator<FileStatus> statusIterator = FileContext.this.listStatus(f);
RemoteIterator<FileStatus> statusIterator =
FileContext.this.listStatus(f);
while(statusIterator.hasNext()) {
FileStatus s = statusIterator.next();
ContentSummary c = s.isDirectory() ? getContentSummary(s.getPath()) :
@ -1626,24 +1627,32 @@ public final class FileContext {
* @throws UnexpectedServerException If server implementation throws
* undeclared exception to RPC server
*/
public Iterator<LocatedFileStatus> listFiles(
public RemoteIterator<LocatedFileStatus> listFiles(
final Path f, final boolean recursive) throws AccessControlException,
FileNotFoundException, UnsupportedFileSystemException,
IOException {
return new Iterator<LocatedFileStatus>() {
private Stack<Iterator<LocatedFileStatus>> itors =
new Stack<Iterator<LocatedFileStatus>>();
Iterator<LocatedFileStatus> curItor = listLocatedStatus(f);
return new RemoteIterator<LocatedFileStatus>() {
private Stack<RemoteIterator<LocatedFileStatus>> itors =
new Stack<RemoteIterator<LocatedFileStatus>>();
RemoteIterator<LocatedFileStatus> curItor = listLocatedStatus(f);
LocatedFileStatus curFile;
/**
* {@inheritDoc}
* @return {@inheritDog}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
* Returns <tt>true</tt> if the iterator has more files.
*
* @return <tt>true</tt> if the iterator has more files.
* @throws AccessControlException if not allowed to access next
* file's status or locations
* @throws FileNotFoundException if next file does not exist any more
* @throws UnsupportedFileSystemException if next file's
* fs is unsupported
* @throws IOException for all other IO errors
* for example, NameNode is not avaialbe or
* NameNode throws IOException due to an error
* while getting the status or block locations
*/
@Override
public boolean hasNext() {
public boolean hasNext() throws IOException {
while (curFile == null) {
if (curItor.hasNext()) {
handleFileStat(curItor.next());
@ -1659,44 +1668,49 @@ public final class FileContext {
/**
* Process the input stat.
* If it is a file, return the file stat.
* If it is a directory, tranverse the directory if recursive is true;
* If it is a directory, traverse the directory if recursive is true;
* ignore it if recursive is false.
* If it is a symlink, resolve the symlink first and then process it
* depending on if it is a file or directory.
* @param stat input status
* @throws RuntimeException if any io error occurs; the io exception
* is set as the cause of RuntimeException
* @throws AccessControlException if access is denied
* @throws FileNotFoundException if file is not found
* @throws UnsupportedFileSystemException if fs is not supported
* @throws IOException for all other IO errors
*/
private void handleFileStat(LocatedFileStatus stat) {
try {
if (stat.isFile()) { // file
curFile = stat;
} else if (stat.isSymlink()) { // symbolic link
// resolve symbolic link
FileStatus symstat = FileContext.this.getFileStatus(
stat.getSymlink());
if (symstat.isFile() || (recursive && symstat.isDirectory())) {
itors.push(curItor);
curItor = listLocatedStatus(stat.getPath());
}
} else if (recursive) { // directory
private void handleFileStat(LocatedFileStatus stat)
throws IOException {
if (stat.isFile()) { // file
curFile = stat;
} else if (stat.isSymlink()) { // symbolic link
// resolve symbolic link
FileStatus symstat = FileContext.this.getFileStatus(
stat.getSymlink());
if (symstat.isFile() || (recursive && symstat.isDirectory())) {
itors.push(curItor);
curItor = listLocatedStatus(stat.getPath());
}
} catch (IOException ioe) {
throw (RuntimeException)new RuntimeException().initCause(ioe);
} else if (recursive) { // directory
itors.push(curItor);
curItor = listLocatedStatus(stat.getPath());
}
}
/**
* {@inheritDoc}
* @return {@inheritDoc}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
* @exception {@inheritDoc}
* Returns the next file's status with its block locations
*
* @throws AccessControlException if not allowed to access next
* file's status or locations
* @throws FileNotFoundException if next file does not exist any more
* @throws UnsupportedFileSystemException if next file's
* fs is unsupported
* @throws IOException for all other IO errors
* for example, NameNode is not avaialbe or
* NameNode throws IOException due to an error
* while getting the status or block locations
*/
@Override
public LocatedFileStatus next() {
public LocatedFileStatus next() throws IOException {
if (hasNext()) {
LocatedFileStatus result = curFile;
curFile = null;
@ -1704,12 +1718,6 @@ public final class FileContext {
}
throw new java.util.NoSuchElementException("No more entry in " + f);
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
}
};
}

97
src/java/org/apache/hadoop/fs/FileSystem.java
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@ -1326,18 +1326,14 @@ public abstract class FileSystem extends Configured implements Closeable {
* If a returned status is a file, it contains the file's block locations.
*
* @param f is the path
* @param filter path filter
*
* @return an iterator that traverses statuses of the files/directories
* in the given path
* If any IO exception (for example the input directory gets deleted while
* listing is being executed), next() or hasNext() of the returned iterator
* may throw a RuntimeException with the IO exception as the cause.
*
* @throws FileNotFoundException If <code>f</code> does not exist
* @throws IOException If an I/O error occurred
*/
public Iterator<LocatedFileStatus> listLocatedStatus(final Path f)
public RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path f)
throws FileNotFoundException, IOException {
return listLocatedStatus(f, DEFAULT_FILTER);
}
@ -1353,50 +1349,28 @@ public abstract class FileSystem extends Configured implements Closeable {
* @throws FileNotFoundException if <code>f</code> does not exist
* @throws IOException if any I/O error occurred
*/
protected Iterator<LocatedFileStatus> listLocatedStatus(final Path f,
protected RemoteIterator<LocatedFileStatus> listLocatedStatus(final Path f,
final PathFilter filter)
throws FileNotFoundException, IOException {
return new Iterator<LocatedFileStatus>() {
return new RemoteIterator<LocatedFileStatus>() {
private final FileStatus[] stats = listStatus(f, filter);
private int i = 0;
/**
* {@inheritDoc}
* @return {@inheritDog}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
*/
@Override
public boolean hasNext() {
return i<stats.length;
}
/**
* {@inheritDoc}
* @return {@inheritDoc}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
* @exception {@inheritDoc}
*/
@Override
public LocatedFileStatus next() {
public LocatedFileStatus next() throws IOException {
if (!hasNext()) {
throw new NoSuchElementException("No more entry in " + f);
}
FileStatus result = stats[i++];
try {
BlockLocation[] locs = result.isFile() ?
BlockLocation[] locs = result.isFile() ?
getFileBlockLocations(result.getPath(), 0, result.getLen()) :
null;
return new LocatedFileStatus(result, locs);
} catch (IOException ioe) {
throw (RuntimeException)new RuntimeException().initCause(ioe);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
return new LocatedFileStatus(result, locs);
}
};
}
@ -1413,30 +1387,22 @@ public abstract class FileSystem extends Configured implements Closeable {
* @param recursive if the subdirectories need to be traversed recursively
*
* @return an iterator that traverses statuses of the files
* If any IO exception (for example a sub-directory gets deleted while
* listing is being executed), next() or hasNext() of the returned iterator
* may throw a RuntimeException with the IO exception as the cause.
*
* @throws FileNotFoundException when the path does not exist;
* IOException see specific implementation
*/
public Iterator<LocatedFileStatus> listFiles(
public RemoteIterator<LocatedFileStatus> listFiles(
final Path f, final boolean recursive)
throws FileNotFoundException, IOException {
return new Iterator<LocatedFileStatus>() {
private Stack<Iterator<LocatedFileStatus>> itors =
new Stack<Iterator<LocatedFileStatus>>();
Iterator<LocatedFileStatus> curItor = listLocatedStatus(f);
LocatedFileStatus curFile;
return new RemoteIterator<LocatedFileStatus>() {
private Stack<RemoteIterator<LocatedFileStatus>> itors =
new Stack<RemoteIterator<LocatedFileStatus>>();
private RemoteIterator<LocatedFileStatus> curItor =
listLocatedStatus(f);
private LocatedFileStatus curFile;
/**
* {@inheritDoc}
* @return {@inheritDog}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
*/
@Override
public boolean hasNext() {
public boolean hasNext() throws IOException {
while (curFile == null) {
if (curItor.hasNext()) {
handleFileStat(curItor.next());
@ -1452,34 +1418,22 @@ public abstract class FileSystem extends Configured implements Closeable {
/**
* Process the input stat.
* If it is a file, return the file stat.
* If it is a directory, tranverse the directory if recursive is true;
* If it is a directory, traverse the directory if recursive is true;
* ignore it if recursive is false.
* @param stat input status
* @throws RuntimeException if any io error occurs; the io exception
* is set as the cause of RuntimeException
* @throws IOException if any IO error occurs
*/
private void handleFileStat(LocatedFileStatus stat) {
try {
if (stat.isFile()) { // file
curFile = stat;
} else if (recursive) { // directory
itors.push(curItor);
curItor = listLocatedStatus(stat.getPath());
}
} catch (IOException ioe) {
throw (RuntimeException)new RuntimeException().initCause(ioe);
private void handleFileStat(LocatedFileStatus stat) throws IOException {
if (stat.isFile()) { // file
curFile = stat;
} else if (recursive) { // directory
itors.push(curItor);
curItor = listLocatedStatus(stat.getPath());
}
}
/**
* {@inheritDoc}
* @return {@inheritDoc}
* @throws Runtimeexception if any IOException occurs during traversal;
* the IOException is set as the cause of the RuntimeException
* @exception {@inheritDoc}
*/
@Override
public LocatedFileStatus next() {
public LocatedFileStatus next() throws IOException {
if (hasNext()) {
LocatedFileStatus result = curFile;
curFile = null;
@ -1487,11 +1441,6 @@ public abstract class FileSystem extends Configured implements Closeable {
}
throw new java.util.NoSuchElementException("No more entry in " + f);
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
}
};
}

2
src/java/org/apache/hadoop/fs/FilterFileSystem.java
View File

@ -167,7 +167,7 @@ public class FilterFileSystem extends FileSystem {
}
/** List files and its block locations in a directory. */
public Iterator<LocatedFileStatus> listLocatedStatus(Path f)
public RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
throws IOException {
return fs.listLocatedStatus(f);
}

42
src/java/org/apache/hadoop/fs/RemoteIterator.java Normal file
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@ -0,0 +1,42 @@
/**
* 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;
import java.io.IOException;
import java.util.NoSuchElementException;
/**
* An iterator over a collection whose elements need to be fetched remotely
*/
public interface RemoteIterator<E> {
/**
* Returns <tt>true</tt> if the iteration has more elements.
*
* @return <tt>true</tt> if the iterator has more elements.
* @throws IOException if any IO error occurs
*/
boolean hasNext() throws IOException;
/**
* Returns the next element in the iteration.
*
* @return the next element in the iteration.
* @throws NoSuchElementException iteration has no more elements.
* @throws IOException if any IO error occurs
*/
E next() throws IOException;
}

2
src/test/core/org/apache/hadoop/fs/FileContextMainOperationsBaseTest.java
View File

@ -282,7 +282,7 @@ public abstract class FileContextMainOperationsBaseTest {
Assert.assertEquals(0, paths.length);
// test listStatus that returns an iterator
Iterator<FileStatus> pathsIterator =
RemoteIterator<FileStatus> pathsIterator =
fc.listStatus(getTestRootPath(fc, "test"));
Assert.assertEquals(getTestRootPath(fc, "test/hadoop"),
pathsIterator.next().getPath());

4
src/test/core/org/apache/hadoop/fs/FileContextSymlinkBaseTest.java
View File

@ -657,7 +657,7 @@ public abstract class FileContextSymlinkBaseTest {
// and link) and LocalFs is 3 (file, link, file crc).
FileStatus[] stats = fc.util().listStatus(link);
assertTrue(stats.length == 2 || stats.length == 3);
Iterator<FileStatus> statsItor = fc.listStatus(link);
RemoteIterator<FileStatus> statsItor = fc.listStatus(link);
int dirLen = 0;
while(statsItor.hasNext()) {
statsItor.next();
@ -1274,7 +1274,7 @@ public abstract class FileContextSymlinkBaseTest {
assertTrue(fc.getFileStatus(dirViaLink).isDirectory());
FileStatus[] stats = fc.util().listStatus(dirViaLink);
assertEquals(0, stats.length);
Iterator<FileStatus> statsItor = fc.listStatus(dirViaLink);
RemoteIterator<FileStatus> statsItor = fc.listStatus(dirViaLink);
assertFalse(statsItor.hasNext());
fc.delete(dirViaLink, false);
assertFalse(exists(fc, dirViaLink));

3
src/test/core/org/apache/hadoop/fs/FileContextURIBase.java
View File

@ -523,7 +523,8 @@ public abstract class FileContextURIBase {
Assert.assertEquals(0, paths.length);
// test listStatus that returns an iterator of FileStatus
Iterator<FileStatus> pathsItor = fc1.listStatus(qualifiedPath("test", fc1));
RemoteIterator<FileStatus> pathsItor =
fc1.listStatus(qualifiedPath("test", fc1));
Assert.assertEquals(qualifiedPath(hPrefix, fc1), pathsItor.next().getPath());
Assert.assertFalse(pathsItor.hasNext());

4
src/test/core/org/apache/hadoop/fs/TestListFiles.java
View File

@ -80,7 +80,7 @@ public class TestListFiles {
fs.mkdirs(TEST_DIR);
writeFile(fs, FILE1, FILE_LEN);
Iterator<LocatedFileStatus> itor = fs.listFiles(
RemoteIterator<LocatedFileStatus> itor = fs.listFiles(
FILE1, true);
LocatedFileStatus stat = itor.next();
assertFalse(itor.hasNext());
@ -107,7 +107,7 @@ public class TestListFiles {
fs.mkdirs(DIR1);
// test empty directory
Iterator<LocatedFileStatus> itor = fs.listFiles(
RemoteIterator<LocatedFileStatus> itor = fs.listFiles(
DIR1, true);
assertFalse(itor.hasNext());
itor = fs.listFiles(DIR1, false);