/*
* Copyright 2013 Cloudera.
*
* Licensed 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 com.cloudera.cdk.data.filesystem;
import com.cloudera.cdk.data.DatasetException;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
class PathIterator implements Iterator<Path>, Iterable<Path> {
private final FileSystem fs;
private final Iterator<Path> directories;
private Iterator<Path> files = null;
public PathIterator(FileSystem fs, Iterable<Path> directories) {
Preconditions.checkArgument(directories != null,
"Directories cannot be null");
this.fs = fs;
this.directories = directories.iterator();
}
@Override
public boolean hasNext() {
if (files != null && files.hasNext()) {
return true;
} else {
return advance();
}
}
@Override
public Path next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return files.next();
}
@Override
public void remove() {
throw new UnsupportedOperationException("Not supported.");
}
private boolean advance() {
while (true) {
if (directories.hasNext()) {
final Path directory = directories.next();
try {
final FileStatus[] stats = fs.listStatus(directory, PathFilters.notHidden());
final List<Path> nextFileSet = Lists.newArrayListWithCapacity(stats.length);
for (FileStatus stat : stats) {
if (stat.isFile()) {
nextFileSet.add(stat.getPath());
}
}
if (nextFileSet.size() > 0) {
this.files = nextFileSet.iterator();
return true;
}
} catch (IOException ex) {
throw new DatasetException("Cannot list files in " + directory, ex);
}
} else {
return false;
}
}
}
@Override
public Iterator<Path> iterator() {
return this;
}
}