Apache
/
hadoop
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

HDFS-12251. Add document for StreamCapabilities. (Lei (Eddy) Xu) 

(cherry picked from commit fe3341786a)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md
This commit is contained in:
Lei Xu 2017-08-04 11:21:58 -07:00
parent ced547d5f0
commit d87a92bf55
1 changed files with 24 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
hadoop-common-project/hadoop-common/src/site/markdown/filesystem/filesystem.md
View File

@ -1199,3 +1199,27 @@ try {
It is notable that this is *not* done in the Hadoop codebase. This does not imply It is notable that this is *not* done in the Hadoop codebase. This does not imply
that robust loops are not recommended —more that the concurrency that robust loops are not recommended —more that the concurrency
problems were not considered during the implementation of these loops. problems were not considered during the implementation of these loops.
## <a name="StreamCapability"></a> interface `StreamCapabilities`
The `StreamCapabilities` provides a way to programmatically query the
capabilities that an `OutputStream` supports.
```java
public interface StreamCapabilities {
boolean hasCapability(String capability);
}
```
### `boolean hasCapability(capability)`
Return true if the `OutputStream` has the desired capability.
The caller can query the capabilities of a stream using a string value.
It currently supports to query:
* `StreamCapabilties.HFLUSH` ("*hflush*"): the capability to flush out the data
in client's buffer.
* `StreamCapabilities.HSYNC` ("*hsync*"): capability to flush out the data in
client's buffer and the disk device.