EventStreamConfig (Wikimedia Event Platform Utilities 1.4.3-SNAPSHOT API)

java.lang.Object
- org.wikimedia.eventutilities.core.event.EventStreamConfig

```
public class EventStreamConfig
extends Object
```
Class to fetch and work with stream configuration from the a URI. Upon instantiation, this will attempt to pre fetch and cache all stream config from streamConfigsUri. Further accesses of uncached stream names will cause a fetch from the result of makeStreamConfigsUriForStreams for the uncached stream names only. Wherever a settingName parameter is used, if it begins with a '/', it will be assumed the settingName is a JsonPointer path, instead of a top level key.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class EventStreamConfig.Builder
Builder, builder pattern to construct EventStreamConfig instances.

Nested Classes
Modifier and Type	Class and Description
`static class`	`EventStreamConfig.Builder` Builder, builder pattern to construct EventStreamConfig instances.

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`EVENT_SERVICE_SETTING` Stream Config setting name for destination event service name.
`protected com.google.common.collect.ImmutableMap<String,URI>`	`eventServiceToUriMap` Maps event service name to a service URL.
`protected EventStreamConfigLoader`	`eventStreamConfigLoader` Used to load stream config at instantiation and on demand.
`static String`	`MESSAGE_KEY_FIELDS_SETTING` Stream config setting name for Kafka message partition keys.
`static String`	`SCHEMA_TITLE_SETTING` Stream Config setting name for schema title.
`protected com.fasterxml.jackson.databind.node.ObjectNode`	`streamConfigsCache` Cached stream configurations.
`static String`	`TOPICS_SETTING` Stream config topics setting.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`EventStreamConfig(EventStreamConfigLoader eventStreamConfigLoader, Map<String,URI> eventServiceToUriMap)` EventStreamConfig constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static EventStreamConfig.Builder`	`builder()` Returns an Builder instance.
`com.fasterxml.jackson.databind.node.ObjectNode`	`cachedStreamConfigs()` Returns all cached stream configs.
`List<String>`	`cachedStreamNames()` Returns all cached stream name keys.
`List<com.fasterxml.jackson.databind.JsonNode>`	`collectAllCachedSettings(String settingName)` Collects all settingName values of every cached stream config entry.
`List<String>`	`collectAllCachedSettingsAsString(String settingName)` Collects all settingName values of every cached stream config entry as a String If the value is an array, its contents will be flattened.
`List<com.fasterxml.jackson.databind.JsonNode>`	`collectSetting(String streamName, String settingName)` Collects the settingName value for streamName.
`List<String>`	`collectSettingAsString(String streamName, String settingName)` Collects the settingName value as a String for streamName.
`List<com.fasterxml.jackson.databind.JsonNode>`	`collectSettingMatchingSettings(String settingName, List<String> streamNames, Map<String,String> settingsFilters)` Collect all settingName values for the list of specified streams with settings that match the provided settingsFilters.
`List<String>`	`collectSettingMatchingSettingsAsString(String settingName, List<String> streamNames, Map<String,String> settingsFilters)` Collect all settingName values as Strings for the list of specified streams with settings that match the provided settingsFilters.
`List<com.fasterxml.jackson.databind.JsonNode>`	`collectSettings(List<String> streamNames, String settingName)` Collects all settingName values for each of the listed streamNames.
`List<String>`	`collectSettingsAsString(List<String> streamNames, String settingName)` Collects all settingName values as a String for each of the listed streamNames.
`List<String>`	`collectTopics(List<String> streamNames)` Get all topics settings for the list of specified streams.
`List<String>`	`collectTopicsMatchingSettings(List<String> streamNames, Map<String,String> settingsFilters)` Get all topics settings for the list of specified streams with settings that match the provided settingsFiilters.
`Stream<com.fasterxml.jackson.databind.JsonNode>`	`elementsStream()` Returns a Java Stream iterator over the stream config entries.
`Stream<Map.Entry<String,com.fasterxml.jackson.databind.JsonNode>>`	`fieldsStream()` Returns a Java Stream iterator over the Map.Entry of stream name to stream config entries.
`com.fasterxml.jackson.databind.node.ObjectNode`	`filterStreamConfigs(List<String> streamNames, Map<String,String> settingsFilters)` Filter stream configs for streamNames that match the settingsFilters.
`List<String>`	`getAllCachedTopics()` Get all topics settings for all known streams.
`String`	`getEventServiceName(String streamName)` Gets the destination_event_service name for the specified stream.
`URI`	`getEventServiceUri(String streamName)` Gets the default event service URI for this stream via the EVENT_SERVICE_SETTING.
`URI`	`getEventServiceUri(String streamName, String datacenter)` Gets a datacenter specific destination event service URI for this stream via the EVENT_SERVICE_SETTING + the datacenter name.
`URI`	`getEventServiceUriByServiceName(String eventServiceName)` Gets the event service POST URI of an event service.
`com.fasterxml.jackson.databind.JsonNode`	`getMessageKeyFields(String streamName)` Get the Kafka message key fields for a given stream.
`String`	`getSchemaTitle(String streamName)` Get all topics settings for the a single stream.
`com.fasterxml.jackson.databind.JsonNode`	`getSetting(String streamName, String settingName)` Gets a stream config setting for a specific stream.
`String`	`getSettingAsString(String streamName, String settingName)` Gets the stream config setting for a specific stream as a string.
`com.fasterxml.jackson.databind.node.ObjectNode`	`getStreamConfig(String streamName)` Returns the stream config entry for a specific stream.
`com.fasterxml.jackson.databind.node.ObjectNode`	`getStreamConfigs(List<String> streamNames)` Gets the stream config entries for the desired stream names.
`List<String>`	`getTopics(String streamName)` Get all topics settings for a single stream.
`protected static List<String>`	`jsonNodesAsText(Collection<com.fasterxml.jackson.databind.JsonNode> jsonNodes)` Converts a List of JsonNodes to a List of Strings using JsonNode::asText.
`protected static List<com.fasterxml.jackson.databind.JsonNode>`	`objectNodeCollectValues(com.fasterxml.jackson.databind.node.ObjectNode objectNode, String fieldName)` Finds all values of fieldName of each element in objectNode.
`void`	`reset()` Re-fetches the content for all stream configs and saves it in the local stream configs cache.
`boolean`	`streamExists(String streamName)` Returns true if the stream is declared in stream config.
`static String`	`toRegex(Collection<String> strings)` Converts a list of strings to a regex that will match any of the strings.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - TOPICS_SETTING
```
public static final String TOPICS_SETTING
```
    Stream config topics setting. Used to get a full list of topics for streams.
    
    See Also:
    
    Constant Field Values
  - SCHEMA_TITLE_SETTING
```
public static final String SCHEMA_TITLE_SETTING
```
    Stream Config setting name for schema title.
    
    See Also:
    
    Constant Field Values
  - EVENT_SERVICE_SETTING
```
public static final String EVENT_SERVICE_SETTING
```
    Stream Config setting name for destination event service name.
    
    See Also:
    
    Constant Field Values
  - MESSAGE_KEY_FIELDS_SETTING
```
public static final String MESSAGE_KEY_FIELDS_SETTING
```
    Stream config setting name for Kafka message partition keys.
    
    See Also:
    
    Constant Field Values
  - eventServiceToUriMap
```
protected com.google.common.collect.ImmutableMap<String,URI> eventServiceToUriMap
```
    Maps event service name to a service URL.
  - eventStreamConfigLoader
```
protected EventStreamConfigLoader eventStreamConfigLoader
```
    Used to load stream config at instantiation and on demand.
  - streamConfigsCache
```
protected com.fasterxml.jackson.databind.node.ObjectNode streamConfigsCache
```
    Cached stream configurations. This maps stream name (or stream pattern regex) to stream config settings.
- Constructor Detail
  - EventStreamConfig
```
protected EventStreamConfig(EventStreamConfigLoader eventStreamConfigLoader,
                            Map<String,URI> eventServiceToUriMap)
```
    EventStreamConfig constructor. This is protected; use EventStreamConfig.builder() to create your EventStreamConfig instance.
- Method Detail
  - builder
```
public static EventStreamConfig.Builder builder()
```
    Returns an Builder instance.
  - reset
```
public final void reset()
```
    Re-fetches the content for all stream configs and saves it in the local stream configs cache. This should fetch and cache all stream configs.
  - elementsStream
```
public Stream<com.fasterxml.jackson.databind.JsonNode> elementsStream()
```
    Returns a Java Stream iterator over the stream config entries. Useful for e.g. map, filter, reduce etc.
  - fieldsStream
```
public Stream<Map.Entry<String,com.fasterxml.jackson.databind.JsonNode>> fieldsStream()
```
    Returns a Java Stream iterator over the Map.Entry of stream name to stream config entries. Useful for e.g. map, filter, reduce etc.
  - filterStreamConfigs
```
public com.fasterxml.jackson.databind.node.ObjectNode filterStreamConfigs(List<String> streamNames,
                                                                          Map<String,String> settingsFilters)
```
    Filter stream configs for streamNames that match the settingsFilters. If streamNames is null, it is assumed you don't want to match on stream names, and only setttingsFilters will be considered. Since settingsFilters must all be strings, this only allows filtering on string stream config settings, or at least ones for which JsonNode.asText() returns something sane (which is true for most primitive types). The keys in settingsFilters are assumed to top level field names, unless the key starts with a '/', in which case it will be assumed to be a JsonPointer.
  - cachedStreamConfigs
```
public com.fasterxml.jackson.databind.node.ObjectNode cachedStreamConfigs()
```
    Returns all cached stream configs.
  - cachedStreamNames
```
public List<String> cachedStreamNames()
```
    Returns all cached stream name keys.
  - streamExists
```
public boolean streamExists(String streamName)
```
    Returns true if the stream is declared in stream config.
  - getStreamConfig
```
public com.fasterxml.jackson.databind.node.ObjectNode getStreamConfig(String streamName)
```
    Returns the stream config entry for a specific stream. This will still return an ObjectNode mapping the stream name to the stream config entry. E.g.
```
   getStreamConfigs(my_stream)
      returns
   { my_stream: { schema_title: my/schema, ... } }
 
```
  - getStreamConfigs
```
public com.fasterxml.jackson.databind.node.ObjectNode getStreamConfigs(List<String> streamNames)
```
    Gets the stream config entries for the desired stream names. Returns a JsonNode map of stream names to stream config entries.
  - getSetting
```
public com.fasterxml.jackson.databind.JsonNode getSetting(String streamName,
                                                          String settingName)
```
    Gets a stream config setting for a specific stream. E.g.
```
 JsonNode setting = getSetting("mediawiki.revision-create", "destination_event_service")
  returns
 TextNode("eventgate-main")
 
```
    You'll still have to pull the value out of the JsonNode wrapper yourself. E.g. setting.asText() or setting.asDouble() If either this streamName does not have a stream config entry, or the stream config entry does not have setting, this returns null.
    Parameters:
    
    streamName - name of stream in stream config
    
    settingName - setting name to get, either top level field name, or JsonPointer starting with '/'.
  - getSettingAsString
```
public String getSettingAsString(String streamName,
                                 String settingName)
```
    Gets the stream config setting for a specific stream as a string. If either this streamName does not have a stream config entry, or the stream config entry does not have setting, this returns null. JsonNode setting = getSettingAsString("mediawiki.revision-create", "destination_event_service") returns "eventgate-main" If either this streamName does not have a stream config entry, or the stream config entry does not have setting, this returns null.
  - collectSetting
```
public List<com.fasterxml.jackson.databind.JsonNode> collectSetting(String streamName,
                                                                    String settingName)
```
    Collects the settingName value for streamName. If the setting value is an array, it will be flattened into a list of JsonNode values.
```
  { stream1: { setting1: [val1, val2] }, stream2: { setting1: [val3, val4] } returns [val1, val2, val3, val4]
  collectSetting("stream2", "setting1") returns [JsonNode("val3"), JsonNode("val4")]
 
```
  - collectSettingAsString
```
public List<String> collectSettingAsString(String streamName,
                                           String settingName)
```
    Collects the settingName value as a String for streamName. If the setting value is an array, it will be flattened into a list of String values.
```
  { stream1: { setting1: [val1, val2] }, stream2: { setting1: [val3, val4] } returns [val1, val2, val3, val4]
  collectSettingAsString("stream2", "setting1") returns ["val3", "val4"]
 
```
  - collectSettings
```
public List<com.fasterxml.jackson.databind.JsonNode> collectSettings(List<String> streamNames,
                                                                     String settingName)
```
    Collects all settingName values for each of the listed streamNames. If any encountered setting values is an array, it will be flattened.
```
  { stream1: { setting1: [val1, val2] }, stream2: { setting1: [val3, val4] } returns [val1, val2, val3, val4]
  collectSettings(["stream1", "stream2"], "setting1") returns [JsonNode("val1"), JsonNode("val2"), JsonNode("val3"), JsonNode("val4")]
 
```
  - collectSettingsAsString
```
public List<String> collectSettingsAsString(List<String> streamNames,
                                            String settingName)
```
    Collects all settingName values as a String for each of the listed streamNames. If any encountered setting values is an array, it will be flattened.
```
   { stream1: { setting1: [val1, val2] }, stream2: { setting1: [val3, val4] } returns [val1, val2, val3, val4]
  collectSettingsAsString(["stream1", "stream2"], "setting1") returns ["val1", "val2", "val3", "val4"]
 
```
  - collectAllCachedSettings
```
public List<com.fasterxml.jackson.databind.JsonNode> collectAllCachedSettings(String settingName)
```
    Collects all settingName values of every cached stream config entry. If the value is an array, its contents will be flattened.
```
  { stream1: { setting1: [val1, val2] }, stream2: { setting1: [val3, val4] } returns [val1, val2, val3, val4]
  collectAllCachedSettings("setting1") returns [JsonNode("val1"), JsonNode("val2"), JsonNode("val3"), JsonNode("val4")]
 
```
  - collectAllCachedSettingsAsString
```
public List<String> collectAllCachedSettingsAsString(String settingName)
```
    Collects all settingName values of every cached stream config entry as a String If the value is an array, its contents will be flattened.
```
   { stream1: { setting1: [val1, val2] }, stream2: { setting1: [val3, val4] } returns [val1, val2, val3, val4]
  collectAllCachedSettingsAsString(setting1") returns ["val1", "val2", "val3", "val4"]
 
```
  - collectSettingMatchingSettings
```
public List<com.fasterxml.jackson.databind.JsonNode> collectSettingMatchingSettings(String settingName,
                                                                                    List<String> streamNames,
                                                                                    Map<String,String> settingsFilters)
```
    Collect all settingName values for the list of specified streams with settings that match the provided settingsFilters. If streamNames null, it is assumed you don't want to match on stream names, and only setttingsFilters will be considered. Since settingsFilters must all be strings, this only allows filtering on string stream config settings, or at least ones for which JsonNode.asText() returns something sane (which is true for most primitive types).
  - collectSettingMatchingSettingsAsString
```
public List<String> collectSettingMatchingSettingsAsString(String settingName,
                                                           List<String> streamNames,
                                                           Map<String,String> settingsFilters)
```
    Collect all settingName values as Strings for the list of specified streams with settings that match the provided settingsFilters. If streamNames is null, it is assumed you don't want to match on stream names, and only setttingsFilters will be considered. Since settingsFilters must all be strings, this only allows filtering on string stream config settings, or at least ones for which JsonNode.asText() returns something sane (which is true for most primitive types).
  - getMessageKeyFields
```
public com.fasterxml.jackson.databind.JsonNode getMessageKeyFields(String streamName)
```
    Get the Kafka message key fields for a given stream.
    
    Parameters:
    
    streamName - the target stream
    
    Returns:
    
    a map of message keys to event keys.
  - getSchemaTitle
```
public String getSchemaTitle(String streamName)
```
    Get all topics settings for the a single stream.
  - getAllCachedTopics
```
public List<String> getAllCachedTopics()
```
    Get all topics settings for all known streams.
  - getTopics
```
public List<String> getTopics(String streamName)
```
    Get all topics settings for a single stream.
  - collectTopics
```
public List<String> collectTopics(List<String> streamNames)
```
    Get all topics settings for the list of specified streams.
  - collectTopicsMatchingSettings
```
public List<String> collectTopicsMatchingSettings(List<String> streamNames,
                                                  Map<String,String> settingsFilters)
```
    Get all topics settings for the list of specified streams with settings that match the provided settingsFiilters. If streamNames is null, it is assumed you don't want to match on stream names, and only setttingsFilters will be considered. Since settingsFilters must all be strings, this only allows filtering on string stream config settings, or at least ones for which JsonNode.asText() returns something sane (which is true for most primitive types).
  - getEventServiceName
```
public String getEventServiceName(String streamName)
```
    Gets the destination_event_service name for the specified stream.
  - toRegex
```
public static String toRegex(Collection<String> strings)
```
    Converts a list of strings to a regex that will match any of the strings. If any of the strings looks like a regex, that is, it starts and ends with a "/" character, the "/" will be removed from the beginning and end of the string before joining into a regex. Example:
```
   ("a", "/^b.+/", "c") returns "(a|^b.+|c)"
 
```
    Use this for converting a list of topics to a regex like:
```
  EventStreamConfig.toRegex(
      eventStreamConfig.getAllCachedTopics()
  );
 
```
  - getEventServiceUriByServiceName
```
public URI getEventServiceUriByServiceName(String eventServiceName)
```
    Gets the event service POST URI of an event service. The URI is looked up in the eventServiceToUriMap. If this the eventServiceName is not defined there, returns null. Note that this function is not looking up anything in the source stream configuration; this is a static configuration provided to this EventStreamConfig class constructor that maps from destination_event_service to a URI. If eventServiceName is not set in eventServiceToUriMap, this throws a RuntimeException.
  - getEventServiceUri
```
public URI getEventServiceUri(String streamName)
```
    Gets the default event service URI for this stream via the EVENT_SERVICE_SETTING.
  - getEventServiceUri
```
public URI getEventServiceUri(String streamName,
                              String datacenter)
```
    Gets a datacenter specific destination event service URI for this stream via the EVENT_SERVICE_SETTING + the datacenter name.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - objectNodeCollectValues
```
protected static List<com.fasterxml.jackson.databind.JsonNode> objectNodeCollectValues(com.fasterxml.jackson.databind.node.ObjectNode objectNode,
                                                                                       String fieldName)
```
    Finds all values of fieldName of each element in objectNode. If the found value is an array, its contents will be flattened. E.g.
```
 { key1: { targetField: val1 }, key2: { targetField: val2 } } returns [val1, val2]
 { key1: { targetField: [val1, val2] }, key2: { targetField: [val3, val4] } returns [val1, val2, val3, val4]
 
```
  - jsonNodesAsText
```
protected static List<String> jsonNodesAsText(Collection<com.fasterxml.jackson.databind.JsonNode> jsonNodes)
```
    Converts a List of JsonNodes to a List of Strings using JsonNode::asText.

Class EventStreamConfig

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

TOPICS_SETTING

SCHEMA_TITLE_SETTING

EVENT_SERVICE_SETTING

MESSAGE_KEY_FIELDS_SETTING

eventServiceToUriMap

eventStreamConfigLoader

streamConfigsCache

Constructor Detail

EventStreamConfig

Method Detail

builder

reset

elementsStream

fieldsStream

filterStreamConfigs

cachedStreamConfigs

cachedStreamNames

streamExists

getStreamConfig

getStreamConfigs

getSetting

getSettingAsString

collectSetting

collectSettingAsString

collectSettings

collectSettingsAsString

collectAllCachedSettings

collectAllCachedSettingsAsString

collectSettingMatchingSettings

collectSettingMatchingSettingsAsString

getMessageKeyFields

getSchemaTitle

getAllCachedTopics

getTopics

collectTopics

collectTopicsMatchingSettings

getEventServiceName

toRegex

getEventServiceUriByServiceName

getEventServiceUri

getEventServiceUri

toString

objectNodeCollectValues

jsonNodesAsText