org.openimaj.hadoop.sequencefile

Class MetadataConfiguration

java.lang.Object

org.openimaj.hadoop.sequencefile.MetadataConfiguration

public class MetadataConfiguration
extends Object

Utility functions for storing and retrieving metadata to be stored in a SequenceFile by the MetadataSequenceFileOutputFormat.

Standard usage would be to use the setMetadata(Map, Configuration) method to add the given metadata to the Configuration in the part of the code that runs locally (i.e. in a Tool.run(String[]) method). The configuration would then be distributed across the cluster, and any mappers or reducers that use the MetadataSequenceFileOutputFormat will automatically have the metadata added to their output file(s).

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Field Summary

Fields

Modifier and Type	Field and Description
static String	COMMENT_KEY Standard key for a comment metadata item
static String	CONTENT_TYPE_KEY Standard key for a storing an indicator of the mime-type of the value fields
static String	UUID_KEY Standard key for a unique identifier metadata item

Method Summary

Methods

Modifier and Type	Method and Description
static org.apache.hadoop.io.SequenceFile.Metadata	getMetadata(org.apache.hadoop.conf.Configuration conf) Read any metadata stored in the Configuration.
static void	setMetadata(Map<String,String> metadata, org.apache.hadoop.conf.Configuration conf) Write the given metadata to the Configuration.

Methods inherited from class java.lang.Object

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

Field Detail

UUID_KEY

public static final String UUID_KEY

Standard key for a unique identifier metadata item

See Also:

Constant Field Values

COMMENT_KEY

public static final String COMMENT_KEY

Standard key for a comment metadata item

See Also:

Constant Field Values

CONTENT_TYPE_KEY

public static final String CONTENT_TYPE_KEY

Standard key for a storing an indicator of the mime-type of the value fields

See Also:

Constant Field Values

Method Detail

getMetadata

public static org.apache.hadoop.io.SequenceFile.Metadata getMetadata(org.apache.hadoop.conf.Configuration conf)

Read any metadata stored in the Configuration.

Parameters:

conf - the configuration

Returns:

the metadata map

setMetadata

public static void setMetadata(Map<String,String> metadata,
               org.apache.hadoop.conf.Configuration conf)

Write the given metadata to the Configuration.

Parameters:

metadata - the metadata.

conf - the configuration.