[TOC]

org.apache.nutch.metadata

Class MetaWrapper

    • All Implemented Interfaces:
    • org.apache.hadoop.conf.Configurable, org.apache.hadoop.io.Writable 
public class MetaWrapper
extends NutchWritable

This is a simple decorator that adds metadata to any Writable-s that can be serialized by NutchWritable. This is useful when data needs to be temporarily enriched during processing, but this temporary metadata doesn't need to be permanently stored after the job is done.

  • Author:
  • Andrzej Bialecki

Constructor Summary

Constructors Constructor and Description MetaWrapper() MetaWrapper(Metadata metadata, org.apache.hadoop.io.Writable instance, org.apache.hadoop.conf.Configuration conf) MetaWrapper(org.apache.hadoop.io.Writable instance, org.apache.hadoop.conf.Configuration conf)

Method Summary

Methods Modifier and Type Method and Description void addMeta(String name, String value) Add metadata. String getMeta(String name) Get metadata. Metadata getMetadata() Get all metadata. String[] getMetaValues(String name) Get multiple metadata. void readFields(DataInput in) void setMeta(String name, String value) Set metadata. void write(DataOutput out) 

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Methods inherited from class org.apache.nutch.crawl.NutchWritable

getTypes 

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Methods inherited from class org.apache.nutch.util.GenericWritableConfigurable

getConf, setConf 

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Methods inherited from class org.apache.hadoop.io.GenericWritable

get, set, toString 

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Methods inherited from class java.lang.Object

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

Constructor Detail

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MetaWrapper

public MetaWrapper()
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MetaWrapper

public MetaWrapper(org.apache.hadoop.io.Writable instance,
           org.apache.hadoop.conf.Configuration conf)
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MetaWrapper

public MetaWrapper(Metadata metadata,
           org.apache.hadoop.io.Writable instance,
           org.apache.hadoop.conf.Configuration conf)

Method Detail

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getMetadata

public Metadata getMetadata()

Get all metadata.

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addMeta

public void addMeta(String name,
           String value)

Add metadata. See Metadata.add(String, String)) for more information.

  - Parameters:
  - <code>name</code> - metadata name
  - <code>value</code> - metadata value       
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setMeta

public void setMeta(String name,
           String value)

Set metadata. See Metadata.set(String, String)) for more information.

  - Parameters:
  - <code>name</code> - 
  - <code>value</code> -        
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getMeta

public String getMeta(String name)

Get metadata. See Metadata.get(String)) for more information.

  - Parameters:
  - <code>name</code> -  
  - Returns:
  - metadata value       
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getMetaValues

public String[] getMetaValues(String name)

Get multiple metadata. See Metadata.getValues(String)) for more information.

  - Parameters:
  - <code>name</code> -  
  - Returns:
  - multiple values       
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readFields

public void readFields(DataInput in)
                throws IOException
  - Specified by: 
  - <code>readFields</code> in interface <code>org.apache.hadoop.io.Writable</code> 
  - Overrides: 
  - <code>readFields</code> in class <code>GenericWritableConfigurable</code> 
  - Throws: 
  - <code>IOException</code>       
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write

public void write(DataOutput out)
           throws IOException
  - Specified by: 
  - <code>write</code> in interface <code>org.apache.hadoop.io.Writable</code> 
  - Overrides: 
  - <code>write</code> in class <code>org.apache.hadoop.io.GenericWritable</code> 
  - Throws: 
  - <code>IOException</code>

Copyright © 2014 The Apache Software Foundation