Package org.apache.nemo.runtime.executor.data.metadata

Class RemoteFileMetadata<K extends java.io.Serializable>

java.lang.Object

org.apache.nemo.runtime.executor.data.metadata.FileMetadata<K>

org.apache.nemo.runtime.executor.data.metadata.RemoteFileMetadata<K>

Type Parameters:

K - the key type of its partitions.

@ThreadSafe
public final class RemoteFileMetadata<K extends java.io.Serializable>
extends FileMetadata<K>

This class represents a metadata for a remote file block. Because the data is stored in a remote file and globally accessed by multiple nodes, each read, or deletion for a block needs one instance of this metadata. The metadata is store in and read from a file (after a remote file block is committed).

Method Summary

Modifier and Type	Method	Description
void	commitBlock()	Write the collected PartitionMetadatas to the metadata file.
static <T extends java.io.Serializable> RemoteFileMetadata<T>	create(java.lang.String metaFilePath)	Creates a new block metadata.
void	deleteMetadata()	Deletes the metadata.
static <T extends java.io.Serializable> RemoteFileMetadata<T>	open(java.lang.String metaFilePath)	Opens a existing block metadata in file.

Methods inherited from class org.apache.nemo.runtime.executor.data.metadata.FileMetadata

getPartitionMetadataList, isCommitted, setCommitted, writePartitionMetadata

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

deleteMetadata

public void deleteMetadata()
                    throws java.io.IOException

Description copied from class: FileMetadata

Deletes the metadata.

Specified by:

deleteMetadata in class FileMetadata<K extends java.io.Serializable>

Throws:

java.io.IOException - if fail to delete.

See Also:

FileMetadata.deleteMetadata()

commitBlock

public void commitBlock()
                 throws java.io.IOException

Write the collected PartitionMetadatas to the metadata file. Notifies that all writes are finished for the block corresponding to this metadata.

Specified by:

commitBlock in class FileMetadata<K extends java.io.Serializable>

Throws:

java.io.IOException - if fail to commit.

create

public static <T extends java.io.Serializable> RemoteFileMetadata<T> create(java.lang.String metaFilePath)

Creates a new block metadata.

Type Parameters:

T - the key type of the block's partitions.

Parameters:

metaFilePath - the path of the file to write metadata.

Returns:

the created block metadata.

open

public static <T extends java.io.Serializable> RemoteFileMetadata<T> open(java.lang.String metaFilePath)
                                                                   throws java.io.IOException

Opens a existing block metadata in file.

Type Parameters:

T - the key type of the block's partitions.

Parameters:

metaFilePath - the path of the file to write metadata.

Returns:

the created block metadata.

Throws:

java.io.IOException - if fail to open.