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HADOOP-6890. Improve listFiles API introduced by HADOOP-6870. Contributed by Hairong Kuang. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@980953 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Hairong Kuang 2010-07-30 20:52:08 +00:00
parent c15ae29a90
commit d0ba178800
5 changed files with 168 additions and 101 deletions
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1
CHANGES.txt
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@ -101,6 +101,7 @@ Trunk (unreleased changes)
HADOOP-6656. Adds a thread in the UserGroupInformation to renew TGTs
periodically. (Owen O'Malley and ddas via ddas)
HADOOP-6890. Improve listFiles API introduced by HADOOP-6870. (hairong)
OPTIMIZATIONS
BUG FIXES

19
src/java/org/apache/hadoop/fs/AbstractFileSystem.java
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@ -786,8 +786,8 @@ public abstract class AbstractFileSystem {
/**
* The specification of this method matches that of
* {@link FileContext#listLocatedStatus(Path)} except that Path f must be for this
* file system.
* {@link FileContext#listLocatedStatus(Path)} except that Path f
* must be for this file system.
*/
protected Iterator<LocatedFileStatus> listLocatedStatus(final Path f)
throws AccessControlException, FileNotFoundException,
@ -795,15 +795,28 @@ public abstract class AbstractFileSystem {
return new Iterator<LocatedFileStatus>() {
private Iterator<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() {
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() {
if (!hasNext()) {
throw new NoSuchElementException();
throw new NoSuchElementException("No more entry in " + f);
}
FileStatus result = itor.next();
try {

213
src/java/org/apache/hadoop/fs/FileContext.java
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@ -1286,103 +1286,21 @@ public final class FileContext {
}
}.resolve(this, absF);
}
/**
* List the statuses and block locations of the files in the given path
* if the path is a directory.
* If the given path is a file, return the file's status and block locations.
* if recursive is true, list all file statuses and block locations in
* the subtree rooted at the given path.
* Files across symbolic links are also returned.
*
* @param f is the path
* @param recursive if the subdirectories need to be traversed recursively
*
* @return an iterator that traverses statuses of the files
*
* @throws AccessControlException If access is denied
* @throws FileNotFoundException If <code>f</code> does not exist
* @throws UnsupportedFileSystemException If file system for <code>f</code> is
* not supported
* @throws IOException If an I/O error occurred
*
* Exceptions applicable to file systems accessed over RPC:
* @throws RpcClientException If an exception occurred in the RPC client
* @throws RpcServerException If an exception occurred in the RPC server
* @throws UnexpectedServerException If server implementation throws
* undeclared exception to RPC server
*/
public Iterator<LocatedFileStatus> listFiles(
final Path f, final boolean recursive) throws AccessControlException,
FileNotFoundException, UnsupportedFileSystemException,
IOException {
return new Iterator<LocatedFileStatus>() {
private Stack<Path> dirs = new Stack<Path>();
private Stack<Path> symLinks = new Stack<Path>();
Iterator<LocatedFileStatus> itor = listLocatedStatus(f);
LocatedFileStatus curFile;
@Override
public boolean hasNext() {
try {
while (curFile == null) {
if (itor.hasNext()) {
handleFileStat(itor.next());
} else if (!dirs.isEmpty()) {
Path dirPath = dirs.pop();
itor = listLocatedStatus(dirPath);
} else if (!symLinks.isEmpty()) {
Path symLink = symLinks.pop();
FileStatus stat = getFileStatus(symLink);
if (stat.isFile() || (recursive && stat.isDirectory())) {
itor = listLocatedStatus(stat.getPath());
}
} else {
return false;
}
}
return true;
} catch (IOException ioe) {
throw (RuntimeException)new RuntimeException().initCause(ioe);
}
}
private void handleFileStat(LocatedFileStatus stat) throws IOException {
if (stat.isFile()) { // file
curFile = stat;
} else if (stat.isSymlink()) { // symbolic link
symLinks.push(stat.getSymlink());
} else if (recursive) { // directory
dirs.push(stat.getPath());
}
}
@Override
public LocatedFileStatus next() {
if (hasNext()) {
LocatedFileStatus result = curFile;
curFile = null;
return result;
}
throw new java.util.NoSuchElementException("No more entry in " + f);
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
}
};
}
/**
* List the statuses of the files/directories in the given path if the path is
* a directory. Each returned status contains a file's block locations.
* a directory.
* Return the file's status and block locations If the path is a file.
*
* If a returned status is a file, it contains the file's block locations.
*
* @param f is the path
*
* @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 AccessControlException If access is denied
* @throws FileNotFoundException If <code>f</code> does not exist
@ -1678,6 +1596,123 @@ public final class FileContext {
}.resolve(FileContext.this, absF);
}
/**
* List the statuses and block locations of the files in the given path.
*
* If the path is a directory,
* if recursive is false, returns files in the directory;
* if recursive is true, return files in the subtree rooted at the path.
* The subtree is traversed in the depth-first order.
* If the path is a file, return the file's status and block locations.
* Files across symbolic links are also returned.
*
* @param f is the path
* @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 AccessControlException If access is denied
* @throws FileNotFoundException If <code>f</code> does not exist
* @throws UnsupportedFileSystemException If file system for <code>f</code>
* is not supported
* @throws IOException If an I/O error occurred
*
* Exceptions applicable to file systems accessed over RPC:
* @throws RpcClientException If an exception occurred in the RPC client
* @throws RpcServerException If an exception occurred in the RPC server
* @throws UnexpectedServerException If server implementation throws
* undeclared exception to RPC server
*/
public Iterator<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);
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() {
while (curFile == null) {
if (curItor.hasNext()) {
handleFileStat(curItor.next());
} else if (!itors.empty()) {
curItor = itors.pop();
} else {
return false;
}
}
return true;
}
/**
* 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;
* 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
*/
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
itors.push(curItor);
curItor = listLocatedStatus(stat.getPath());
}
} catch (IOException ioe) {
throw (RuntimeException)new RuntimeException().initCause(ioe);
}
}
/**
* {@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() {
if (hasNext()) {
LocatedFileStatus result = curFile;
curFile = null;
return result;
}
throw new java.util.NoSuchElementException("No more entry in " + f);
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove is not supported");
}
};
}
/**
* <p>Return all the files that match filePattern and are not checksum
* files. Results are sorted by their names.

29
src/java/org/apache/hadoop/fs/FileSystem.java
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@ -1320,16 +1320,22 @@ public abstract class FileSystem extends Configured implements Closeable {
}
/**
* List the statuses and block locations of the files in the given path
* if the path is a directory.
* If the given path is a file, return the file's status and block locations.
* if recursive is true, list all file statuses and block locations in
* the subtree rooted at the given path.
* List the statuses and block locations of the files in the given path.
*
* If the path is a directory,
* if recursive is false, returns files in the directory;
* if recursive is true, return files in the subtree rooted at the path.
* If the path is a file, return the file's status and block locations.
* Files across symbolic links are also returned.
*
* @param f is the path
* @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
*/
@ -1344,6 +1350,12 @@ public abstract class FileSystem extends Configured implements Closeable {
list(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() {
if (fileStats.isEmpty()) {
@ -1382,6 +1394,13 @@ public abstract class FileSystem extends Configured implements Closeable {
}
}
/**
* {@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() {
if (!hasNext()) {

7
src/test/core/org/apache/hadoop/fs/TestListFiles.java
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@ -106,15 +106,15 @@ public class TestListFiles {
public void testDirectory() throws IOException {
fs.mkdirs(DIR1);
// test empty directory
Iterator<LocatedFileStatus> itor = fs.listFiles(
DIR1, true);
assertFalse(itor.hasNext());
itor = fs.listFiles(DIR1, false);
assertFalse(itor.hasNext());
writeFile(fs, FILE2, FILE_LEN);
// test empty directory
// testing directory with 1 file
writeFile(fs, FILE2, FILE_LEN);
itor = fs.listFiles(DIR1, true);
LocatedFileStatus stat = itor.next();
assertFalse(itor.hasNext());
@ -123,7 +123,6 @@ public class TestListFiles {
assertEquals(fs.makeQualified(FILE2), stat.getPath());
assertEquals(1, stat.getBlockLocations().length);
// testing directory with 1 file
itor = fs.listFiles(DIR1, false);
stat = itor.next();
assertFalse(itor.hasNext());