org.apache.solr.common.cloud

Class Aliases

java.lang.Object

org.apache.solr.common.cloud.Aliases

public class Aliases
extends Object

Holds collection aliases -- virtual collections that point to one or more other collections. We might add other types of aliases here some day. Immutable.

Field Summary

Fields

Modifier and Type	Field and Description
static Aliases	EMPTY An empty, minimal Aliases primarily used to support the non-cloud solr use cases.

Method Summary

Modifier and Type	Method and Description
Aliases	cloneWithCollectionAlias(String alias, String collections) Creates a new Aliases instance with the same data as the current one but with a modification based on the parameters.
Aliases	cloneWithCollectionAliasMetadata(String alias, String metadataKey, String metadataValue) Set the value for some metadata on a collection alias.
static Map<String,List<String>>	convertMapOfCommaDelimitedToMapOfList(Map<String,String> collectionAliasMap)
static Map<String,String>	convertMapOfListToMapOfCommaDelimited(Map<String,List<String>> collectionAliasMap)
static Aliases	fromJSON(byte[] bytes, int zNodeVersion) Create an instance from the JSON bytes read from zookeeper.
Map<String,List<String>>	getCollectionAliasListMap() Get a fully parsed map of collection aliases.
Map<String,String>	getCollectionAliasMap() Get a map similar to the JSON data as stored in zookeeper.
Map<String,String>	getCollectionAliasMetadata(String alias) Returns an unmodifiable Map of metadata for a given alias.
int	getZNodeVersion()
List<String>	resolveAliases(String aliasName) List the collections associated with a particular alias.
static List<String>	resolveAliasesGivenAliasMap(Map<String,List<String>> collectionAliasListMap, String aliasName)
byte[]	toJSON() Serialize our state.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY

public static final Aliases EMPTY

An empty, minimal Aliases primarily used to support the non-cloud solr use cases. Not normally useful in cloud situations where the version of the node needs to be tracked even if all aliases are removed. A version of 0 is provided rather than -1 to minimize the possibility that if this is used in a cloud instance data is written without version checking.

Method Detail

fromJSON

public static Aliases fromJSON(byte[] bytes,
                               int zNodeVersion)

Create an instance from the JSON bytes read from zookeeper. Generally this should only be done by a ZkStateReader.

Parameters:

bytes - The bytes read via a getData request to zookeeper (possibly null)

zNodeVersion - the version of the data in zookeeper that this instance corresponds to

Returns:

A new immutable Aliases object

toJSON

public byte[] toJSON()

Serialize our state.

convertMapOfCommaDelimitedToMapOfList

public static Map<String,List<String>> convertMapOfCommaDelimitedToMapOfList(Map<String,String> collectionAliasMap)

convertMapOfListToMapOfCommaDelimited

public static Map<String,String> convertMapOfListToMapOfCommaDelimited(Map<String,List<String>> collectionAliasMap)

getZNodeVersion

public int getZNodeVersion()

getCollectionAliasMap

public Map<String,String> getCollectionAliasMap()

Get a map similar to the JSON data as stored in zookeeper. Callers may prefer use of getCollectionAliasListMap() instead, if collection names will be iterated.

Returns:

an unmodifiable Map of collection aliases mapped to a comma delimited string of the collection(s) the alias maps to. Does not return null.

getCollectionAliasListMap

public Map<String,List<String>> getCollectionAliasListMap()

Get a fully parsed map of collection aliases.

Returns:

an unmodifiable Map of collection aliases mapped to a list of the collection(s) the alias maps to. Does not return null.

getCollectionAliasMetadata

public Map<String,String> getCollectionAliasMetadata(String alias)

Returns an unmodifiable Map of metadata for a given alias. If an alias by the given name exists, this method will never return null.

Parameters:

alias - the name of an alias also found as a key in getCollectionAliasListMap()

Returns:

The metadata for the alias (possibly empty) or null if the alias does not exist.

resolveAliases

public List<String> resolveAliases(String aliasName)

List the collections associated with a particular alias. One level of alias indirection is supported (alias to alias to collection). Such indirection may be deprecated in the future, use with caution.

Returns:

An unmodifiable list of collections names that the input alias name maps to. If there are none, the input is returned.

resolveAliasesGivenAliasMap

public static List<String> resolveAliasesGivenAliasMap(Map<String,List<String>> collectionAliasListMap,
                                                       String aliasName)

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

cloneWithCollectionAlias

public Aliases cloneWithCollectionAlias(String alias,
                                        String collections)

Creates a new Aliases instance with the same data as the current one but with a modification based on the parameters.

Note that the state in zookeeper is unaffected by this method and the change must still be persisted via ZkStateReader.AliasesManager.applyModificationAndExportToZk(UnaryOperator)

Parameters:

alias - the alias to update, must not be null

collections - the comma separated list of collections for the alias, null to remove the alias

cloneWithCollectionAliasMetadata

public Aliases cloneWithCollectionAliasMetadata(String alias,
                                                String metadataKey,
                                                String metadataValue)

Set the value for some metadata on a collection alias. This is done by creating a new Aliases instance with the same data as the current one but with a modification based on the parameters.

Note that the state in zookeeper is unaffected by this method and the change must still be persisted via ZkStateReader.AliasesManager.applyModificationAndExportToZk(UnaryOperator)

Parameters:

alias - the alias to update

metadataKey - the key for the metadata

metadataValue - the metadata to add/replace, null to remove the key.

Returns:

An immutable copy of the aliases with the new metadata.

toString

public String toString()

Overrides:

toString in class Object