Package org.apache.nutch.metadata

Class Metadata

java.lang.Object

org.apache.nutch.metadata.Metadata

All Implemented Interfaces:

Writable, CreativeCommons, DublinCore, Feed, HttpHeaders, Nutch

Direct Known Subclasses:

CaseInsensitiveMetadata, SpellCheckedMetadata

public class Metadata
extends Object
implements Writable, CreativeCommons, DublinCore, HttpHeaders, Nutch, Feed

A multi-valued metadata container.

Field Summary

Fields

Modifier and Type	Field	Description
protected Map<String,String[]>	metadata	A map of all metadata attributes.

Fields inherited from interface org.apache.nutch.metadata.CreativeCommons

LICENSE_LOCATION, LICENSE_URL, WORK_TYPE

Fields inherited from interface org.apache.nutch.metadata.DublinCore

CONTRIBUTOR, COVERAGE, CREATOR, DATE, DESCRIPTION, FORMAT, IDENTIFIER, LANGUAGE, MODIFIED, PUBLISHER, RELATION, RIGHTS, SOURCE, SUBJECT, TITLE, TYPE

Fields inherited from interface org.apache.nutch.metadata.Feed

FEED, FEED_AUTHOR, FEED_PUBLISHED, FEED_TAGS, FEED_UPDATED

Fields inherited from interface org.apache.nutch.metadata.HttpHeaders

CLIENT_TRANSFER_ENCODING, CONTENT_DISPOSITION, CONTENT_ENCODING, CONTENT_LANGUAGE, CONTENT_LENGTH, CONTENT_LOCATION, CONTENT_MD5, CONTENT_TYPE, IF_MODIFIED_SINCE, LAST_MODIFIED, LOCATION, TRANSFER_ENCODING, USER_AGENT, WRITABLE_CONTENT_TYPE

Fields inherited from interface org.apache.nutch.metadata.Nutch

ARG_CRAWLDB, ARG_HOSTDB, ARG_LINKDB, ARG_SEEDDIR, ARG_SEEDNAME, ARG_SEGMENTDIR, ARG_SEGMENTS, CACHING_FORBIDDEN_ALL, CACHING_FORBIDDEN_CONTENT, CACHING_FORBIDDEN_KEY, CACHING_FORBIDDEN_NONE, CHAR_ENCODING_FOR_CONVERSION, CRAWL_ID_KEY, FETCH_EVENT_CONTENTLANG, FETCH_EVENT_CONTENTTYPE, FETCH_EVENT_FETCHTIME, FETCH_EVENT_SCORE, FETCH_EVENT_TITLE, FETCH_STATUS_KEY, FETCH_TIME_KEY, FIXED_INTERVAL_KEY, GENERATE_TIME_KEY, ORIGINAL_CHAR_ENCODING, PROTO_STATUS_KEY, PROTOCOL_STATUS_CODE_KEY, REPR_URL_KEY, ROBOTS_METATAG, SCORE_KEY, SEGMENT_NAME_KEY, SIGNATURE_KEY, STAT_PROGRESS, VAL_RESULT, WRITABLE_FIXED_INTERVAL_KEY, WRITABLE_GENERATE_TIME_KEY, WRITABLE_PROTO_STATUS_KEY, WRITABLE_REPR_URL_KEY

Constructor Summary

Constructors

Constructor	Description
Metadata()	Constructs a new, empty metadata.

Method Summary

Modifier and Type	Method	Description
void	add(String name, String value)	Add a metadata name/value mapping.
void	addAll(Metadata metadata)	Add all name/value mappings (merge two metadata mappings).
void	clear()	Remove all mappings from metadata.
boolean	equals(Object o)
String	get(String name)	Get the value associated to a metadata name.
String[]	getValues(String name)	Get the values associated to a metadata name.
boolean	isMultiValued(String name)	Returns true if named value is multivalued.
String[]	names()	Returns an array of the names contained in the metadata.
void	readFields(DataInput in)
void	remove(String name)	Remove a metadata and all its associated values.
void	set(String name, String value)	Set metadata name/value.
void	setAll(Properties properties)	Copy All key-value pairs from properties.
int	size()	Returns the number of metadata names in this metadata.
String	toString()
String	toString(String separator, String keyValueSeparator)
void	write(DataOutput out)

Methods inherited from class java.lang.Object

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

Field Detail

metadata

protected Map<String,String[]> metadata

A map of all metadata attributes.

Constructor Detail

Metadata

public Metadata()

Constructs a new, empty metadata.

Method Detail

isMultiValued

public boolean isMultiValued(String name)

Returns true if named value is multivalued.

Parameters:

name - name of metadata

Returns:

true is named value is multivalued, false if single value or null

names

public String[] names()

Returns an array of the names contained in the metadata.

Returns:

Metadata names

get

public String get(String name)

Get the value associated to a metadata name. If many values are associated to the specified name, then the first one is returned.

Parameters:

name - of the metadata.

Returns:

the value associated to the specified metadata name.

getValues

public String[] getValues(String name)

Get the values associated to a metadata name.

Parameters:

name - of the metadata.

Returns:

the values associated to a metadata name.

add

public void add(String name,
                String value)

Add a metadata name/value mapping. Add the specified value to the list of values associated to the specified metadata name.

Parameters:

name - the metadata name.

value - the metadata value.

addAll

public void addAll(Metadata metadata)

Add all name/value mappings (merge two metadata mappings). If a name already exists in current metadata the values are added to existing values.

Parameters:

metadata - other Metadata to be merged

setAll

public void setAll(Properties properties)

Copy All key-value pairs from properties.

Parameters:

properties - properties to copy from

set

public void set(String name,
                String value)

Set metadata name/value. Associate the specified value to the specified metadata name. If some previous values were associated to this name, they are removed.

Parameters:

name - the metadata name.

value - the metadata value.

remove

public void remove(String name)

Remove a metadata and all its associated values.

Parameters:

name - metadata name to remove

size

public int size()

Returns the number of metadata names in this metadata.

Returns:

number of metadata names

clear

public void clear()

Remove all mappings from metadata.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

toString

public String toString(String separator,
                       String keyValueSeparator)

Parameters:

separator - separator between Metadata's key-value pairs

keyValueSeparator - separator between key and value

Returns:

list of all key-value pairs in Metadata using the provided separators

write

public final void write(DataOutput out)
                 throws IOException

Specified by:

write in interface Writable

Throws:

IOException

readFields

public final void readFields(DataInput in)
                      throws IOException

Specified by:

readFields in interface Writable

Throws:

IOException