imbajin commented on code in PR #571:
URL:
https://github.com/apache/incubator-hugegraph-toolchain/pull/571#discussion_r1474214018
##########
hugegraph-loader/src/main/java/org/apache/hugegraph/loader/reader/hdfs/HDFSFileReader.java:
##########
@@ -109,7 +125,18 @@ protected List<Readable> scanReadables() throws
IOException {
paths.add(new HDFSFile(this.hdfs, path));
} else {
assert this.hdfs.isDirectory(path);
- FileStatus[] statuses = this.hdfs.listStatus(path);
+ FileStatus[] statuses;
+ if (prefix == null || prefix.isEmpty()) {
+ statuses = this.hdfs.listStatus(path);
+ } else {
+ PathFilter prefixFilter = new PathFilter() {
+ @Override
+ public boolean accept(Path path) {
+ return path.getName().startsWith(prefix);
+ }
+ };
+ statuses = this.hdfs.listStatus(path,prefixFilter);
+ }
Review Comment:
maybe we could not list all HDFS_Path together(may occupy large memory) ,
use iterator to scan it?
Add a gist here:
```java
assert status.isDirectory();
RemoteIterator<FileStatus> iter = this.hdfs.listStatusIterator(path);
while (iter.hasNext()) {
FileStatus subStatus = iter.next();
// check file/dirname StartWith prefiex & passed filter
if ((prefix == null || prefix.isEmpty() ||
subStatus.getPath().getName().startsWith(prefix)) &&
filter.reserved(subStatus.getPath().getName())) {
paths.add(new HDFSFile(this.hdfs, subStatus.getPath()));
}
}
```
if we want to scan files recursively: (maybe better to consider BFS way? not
list all together)
```java
assert this.hdfs.isDirectory(path);
RemoteIterator<FileStatus> iter =
this.hdfs.listStatusIterator(path);
while (iter.hasNext()) {
FileStatus subStatus = iter.next();
if (subStatus.isFile()) {
if (filter.reserved(subStatus.getPath().getName())) {
paths.add(new HDFSFile(this.hdfs,
subStatus.getPath()));
}
} else {
assert subStatus.isDirectory();
Path[] subPaths =
FileUtil.stat2Paths(this.hdfs.listStatus(subStatus.getPath()));
for (Path subPath : subPaths) {
if (filter.reserved(subPath.getName())) {
paths.add(new HDFSFile(this.hdfs, subPath));
}
}
}
}
```
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