Package org.camunda.bpm.client.impl

Class ExternalTaskClientBuilderImpl

java.lang.Object

org.camunda.bpm.client.impl.ExternalTaskClientBuilderImpl

All Implemented Interfaces:

ExternalTaskClientBuilder

public class ExternalTaskClientBuilderImpl
extends Object
implements ExternalTaskClientBuilder

Author:

Tassilo Weidner

Field Summary

Fields

Modifier and Type	Field	Description
protected Long	asyncResponseTimeout
protected BackoffStrategy	backoffStrategy
protected String	dateFormat
protected String	defaultSerializationFormat
protected DeserializationTypeValidator	deserializationTypeValidator
protected EngineClient	engineClient
protected org.apache.hc.client5.http.impl.classic.HttpClientBuilder	httpClientBuilder
protected List<ClientRequestInterceptor>	interceptors
protected boolean	isAutoFetchingEnabled
protected boolean	isBackoffStrategyDisabled
protected long	lockDuration
protected static final ExternalTaskClientLogger	LOG
protected int	maxTasks
protected com.fasterxml.jackson.databind.ObjectMapper	objectMapper
protected OrderingConfig	orderingConfig
protected TopicSubscriptionManager	topicSubscriptionManager
protected TypedValues	typedValues
protected UrlResolver	urlResolver
protected boolean	usePriority
protected ValueMappers	valueMappers
protected String	workerId

Constructor Summary

Constructors

Constructor	Description
ExternalTaskClientBuilderImpl()

Method Summary

Modifier and Type	Method	Description
ExternalTaskClientBuilder	addInterceptor(ClientRequestInterceptor interceptor)	Adds an interceptor to change a request before it is sent to the http server.
protected void	applyConfigurator(Map<String,DataFormat> dataFormats, DataFormatConfigurator configurator)
protected void	applyConfigurators(Map<String,DataFormat> dataFormats)
ExternalTaskClientBuilder	asc()	Fluent API method to configure Ascending order on the associated field.
ExternalTaskClientBuilder	asyncResponseTimeout(long asyncResponseTimeout)	Asynchronous response (long polling) is enabled if a timeout is given.
ExternalTaskClientBuilder	backoffStrategy(BackoffStrategy backoffStrategy)	Adds a custom strategy to the client for defining the org.camunda.bpm.client.backoff between two requests.
ExternalTaskClientBuilder	baseUrl(String baseUrl)	Base url of the Camunda BPM Platform REST API.
ExternalTaskClient	build()	Bootstraps the Camunda client
String	checkHostname()
protected void	checkInterceptors()
ExternalTaskClientBuilder	customizeHttpClient(Consumer<org.apache.hc.client5.http.impl.classic.HttpClientBuilder> httpClientConsumer)	Exposes the internal Apache HttpClientBuilder for custom client configurations.
ExternalTaskClientBuilder	dateFormat(String dateFormat)	Specifies the date format to de-/serialize date variables.
ExternalTaskClientBuilder	defaultSerializationFormat(String defaultSerializationFormat)	Specifies the serialization format that is used to serialize objects when no specific format is requested.
ExternalTaskClientBuilder	desc()	Fluent API method to configure Descending order on the associated field.
ExternalTaskClientBuilder	deserializationTypeValidator(DeserializationTypeValidator deserializationTypeValidator)	Configures validation of the Java type that object variables are deserialized into, resolved from the (attacker-influenceable) objectTypeName variable metadata received from the engine.
ExternalTaskClientBuilder	disableAutoFetching()	Disables immediate fetching for external tasks after calling ExternalTaskClientBuilder.build() to bootstrap the client.
ExternalTaskClientBuilder	disableBackoffStrategy()	Disables the client-side backoff strategy.
protected Long	getAsyncResponseTimeout()
protected BackoffStrategy	getBackoffStrategy()
String	getBaseUrl()
String	getDateFormat()
String	getDefaultSerializationFormat()
EngineClient	getEngineClient()
String	getHostname()
protected List<ClientRequestInterceptor>	getInterceptors()
protected long	getLockDuration()
protected int	getMaxTasks()
com.fasterxml.jackson.databind.ObjectMapper	getObjectMapper()
TypedValues	getTypedValues()
ValueMappers	getValueMappers()
protected String	getWorkerId()
protected void	initBaseUrl()
protected void	initEngineClient()
protected void	initObjectMapper()
protected void	initTopicSubscriptionManager()
protected void	initVariableMappers()
protected void	initWorkerId()
protected boolean	isAutoFetchingEnabled()
ExternalTaskClientBuilder	lockDuration(long lockDuration)
protected void	lookupCustomDataFormats(Map<String,DataFormat> dataFormats)
protected Map<String,DataFormat>	lookupDataFormats()
protected void	lookupProvider(Map<String,DataFormat> dataFormats, DataFormatProvider provider)
ExternalTaskClientBuilder	maxTasks(int maxTasks)	Specifies the maximum amount of tasks that can be fetched within one request.
ExternalTaskClientBuilder	orderByCreateTime()	Fluent API method for configuring createTime as a sorting criterion for fetching of the tasks.
protected String	sanitizeUrl(String url)
ExternalTaskClientBuilder	urlResolver(UrlResolver urlResolver)	Url resolver of the Camunda 7 REST API.
ExternalTaskClientBuilder	useCreateTime(boolean useCreateTime)	Specifies whether tasks should be fetched based on their create time.
ExternalTaskClientBuilder	usePriority(boolean usePriority)	Specifies whether tasks should be fetched based on their priority or arbitrarily.
ExternalTaskClientBuilder	workerId(String workerId)	A custom worker id the Workflow Engine is aware of.

Methods inherited from class java.lang.Object

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

Field Details

LOG

protected static final ExternalTaskClientLogger LOG

workerId

protected String workerId

maxTasks

protected int maxTasks

usePriority

protected boolean usePriority

orderingConfig

protected OrderingConfig orderingConfig

asyncResponseTimeout

protected Long asyncResponseTimeout

lockDuration

protected long lockDuration

defaultSerializationFormat

protected String defaultSerializationFormat

dateFormat

protected String dateFormat

objectMapper

protected com.fasterxml.jackson.databind.ObjectMapper objectMapper

valueMappers

protected ValueMappers valueMappers

typedValues

protected TypedValues typedValues

engineClient

protected EngineClient engineClient

topicSubscriptionManager

protected TopicSubscriptionManager topicSubscriptionManager

httpClientBuilder

protected org.apache.hc.client5.http.impl.classic.HttpClientBuilder httpClientBuilder

interceptors

protected List<ClientRequestInterceptor> interceptors

isAutoFetchingEnabled

protected boolean isAutoFetchingEnabled

backoffStrategy

protected BackoffStrategy backoffStrategy

isBackoffStrategyDisabled

protected boolean isBackoffStrategyDisabled

urlResolver

protected UrlResolver urlResolver

deserializationTypeValidator

protected DeserializationTypeValidator deserializationTypeValidator

Constructor Details

ExternalTaskClientBuilderImpl

public ExternalTaskClientBuilderImpl()

Method Details

baseUrl

public ExternalTaskClientBuilder baseUrl(String baseUrl)

Description copied from interface: ExternalTaskClientBuilder

Base url of the Camunda BPM Platform REST API. This information is mandatory.

If this method is used, it will create a permanent url resolver with the given baseUrl.

Specified by:

baseUrl in interface ExternalTaskClientBuilder

Parameters:

baseUrl - of the Camunda BPM Platform REST API

Returns:

the builder

urlResolver

public ExternalTaskClientBuilder urlResolver(UrlResolver urlResolver)

Description copied from interface: ExternalTaskClientBuilder

Url resolver of the Camunda 7 REST API. This information is mandatory.

If the server is in a cluster or you are using spring cloud, you can create a class which implements UrlResolver..

this is a sample for spring cloud DiscoveryClient

 {@code
 public class CustomUrlResolver implements UrlResolver{
 protected String serviceId;

 protected DiscoveryClient discoveryClient;

   protected String getRandomServiceInstance() {
     List serviceInstances = discoveryClient.getInstances(serviceId);
     Random random = new Random();

     return serviceInstances.get(random.nextInt(serviceInstances.size())).getUri().toString();
   }

   public String getBaseUrl() {
     return getRandomServiceInstance();
   }
 }
 </pre>
 @param urlResolver of the Camunda 7 REST API
 @return the builder

Specified by:

urlResolver in interface ExternalTaskClientBuilder

workerId

public ExternalTaskClientBuilder workerId(String workerId)

Description copied from interface: ExternalTaskClientBuilder

A custom worker id the Workflow Engine is aware of. This information is optional. Note: make sure to choose a unique worker id

If not given or null, a worker id is generated automatically which consists of the hostname as well as a random and unique 128 bit string (UUID).

Specified by:

workerId in interface ExternalTaskClientBuilder

Parameters:

workerId - the Workflow Engine is aware of

Returns:

the builder

addInterceptor

public ExternalTaskClientBuilder addInterceptor(ClientRequestInterceptor interceptor)

Description copied from interface: ExternalTaskClientBuilder

Adds an interceptor to change a request before it is sent to the http server. This information is optional.

Specified by:

addInterceptor in interface ExternalTaskClientBuilder

Parameters:

interceptor - which changes the request

Returns:

the builder

maxTasks

public ExternalTaskClientBuilder maxTasks(int maxTasks)

Description copied from interface: ExternalTaskClientBuilder

Specifies the maximum amount of tasks that can be fetched within one request. This information is optional. Default is 10.

Specified by:

maxTasks in interface ExternalTaskClientBuilder

Parameters:

maxTasks - which are supposed to be fetched within one request

Returns:

the builder

usePriority

public ExternalTaskClientBuilder usePriority(boolean usePriority)

Description copied from interface: ExternalTaskClientBuilder

Specifies whether tasks should be fetched based on their priority or arbitrarily. This information is optional. Default is true.

Specified by:

usePriority in interface ExternalTaskClientBuilder

Parameters:

usePriority - when fetching and locking tasks

Returns:

the builder

useCreateTime

public ExternalTaskClientBuilder useCreateTime(boolean useCreateTime)

Description copied from interface: ExternalTaskClientBuilder

Specifies whether tasks should be fetched based on their create time. If useCreateTime is passed using true, the tasks are going to be fetched in Descending order, otherwise false will not consider create time.

Specified by:

useCreateTime in interface ExternalTaskClientBuilder

Parameters:

useCreateTime - the flag to control whether create time should be considered as a desc sorting criterion (newer tasks will be returned first)

Returns:

the builder

orderByCreateTime

public ExternalTaskClientBuilder orderByCreateTime()

Description copied from interface: ExternalTaskClientBuilder

Fluent API method for configuring createTime as a sorting criterion for fetching of the tasks. Can be used in conjunction with asc or desc methods to configure the respective order for createTime. The method needs to be called first before specifying the order.

Specified by:

orderByCreateTime in interface ExternalTaskClientBuilder

Returns:

the builder

asc

public ExternalTaskClientBuilder asc()

Description copied from interface: ExternalTaskClientBuilder

Fluent API method to configure Ascending order on the associated field. Used in conjunction with an orderBy method such as orderByCreateTime.

Specified by:

asc in interface ExternalTaskClientBuilder

Returns:

the builder

desc

public ExternalTaskClientBuilder desc()

Description copied from interface: ExternalTaskClientBuilder

Fluent API method to configure Descending order on the associated field. Used in conjunction with an orderBy method such as orderByCreateTime.

Specified by:

desc in interface ExternalTaskClientBuilder

Returns:

the builder

asyncResponseTimeout

public ExternalTaskClientBuilder asyncResponseTimeout(long asyncResponseTimeout)

Description copied from interface: ExternalTaskClientBuilder

Asynchronous response (long polling) is enabled if a timeout is given. Specifies the maximum waiting time for the response of fetched and locked external tasks. The response is performed immediately, if external tasks are available in the moment of the request. This information is optional. Unless a timeout is given, fetch and lock responses are synchronous.

Specified by:

asyncResponseTimeout in interface ExternalTaskClientBuilder

Parameters:

asyncResponseTimeout - of fetched and locked external tasks in milliseconds

Returns:

the builder

lockDuration

public ExternalTaskClientBuilder lockDuration(long lockDuration)

Specified by:

lockDuration in interface ExternalTaskClientBuilder

Parameters:

lockDuration -

• in milliseconds to lock the external tasks
• must be greater than zero
• the default lock duration is 20 seconds (20,000 milliseconds)
• is overridden by the lock duration configured on a topic subscription

Returns:

the builder

disableAutoFetching

public ExternalTaskClientBuilder disableAutoFetching()

Description copied from interface: ExternalTaskClientBuilder

Disables immediate fetching for external tasks after calling ExternalTaskClientBuilder.build() to bootstrap the client. To start fetching ExternalTaskClient.start() must be called.

Specified by:

disableAutoFetching in interface ExternalTaskClientBuilder

Returns:

the builder

backoffStrategy

public ExternalTaskClientBuilder backoffStrategy(BackoffStrategy backoffStrategy)

Description copied from interface: ExternalTaskClientBuilder

Adds a custom strategy to the client for defining the org.camunda.bpm.client.backoff between two requests. This information is optional. By default ExponentialBackoffStrategy is applied.

Specified by:

backoffStrategy in interface ExternalTaskClientBuilder

Parameters:

backoffStrategy - which realizes a custom org.camunda.bpm.client.backoff strategy

Returns:

the builder

disableBackoffStrategy

public ExternalTaskClientBuilder disableBackoffStrategy()

Description copied from interface: ExternalTaskClientBuilder

Disables the client-side backoff strategy. On invocation, the configuration option ExternalTaskClientBuilder.backoffStrategy(org.camunda.bpm.client.backoff.BackoffStrategy) is ignored.

NOTE: Please bear in mind that disabling the client-side backoff can lead to heavy load situations on engine side. To avoid this, please specify an appropriate ExternalTaskClientBuilder.asyncResponseTimeout(long).

Specified by:

disableBackoffStrategy in interface ExternalTaskClientBuilder

Returns:

the builder

defaultSerializationFormat

public ExternalTaskClientBuilder defaultSerializationFormat(String defaultSerializationFormat)

Description copied from interface: ExternalTaskClientBuilder

Specifies the serialization format that is used to serialize objects when no specific format is requested. This option defaults to application/json.

Specified by:

defaultSerializationFormat in interface ExternalTaskClientBuilder

Parameters:

defaultSerializationFormat - serialization format to be used

Returns:

the builder

dateFormat

public ExternalTaskClientBuilder dateFormat(String dateFormat)

Description copied from interface: ExternalTaskClientBuilder

Specifies the date format to de-/serialize date variables.

Specified by:

dateFormat in interface ExternalTaskClientBuilder

Parameters:

dateFormat - date format to be used

Returns:

the builder

customizeHttpClient

public ExternalTaskClientBuilder customizeHttpClient(Consumer<org.apache.hc.client5.http.impl.classic.HttpClientBuilder> httpClientConsumer)

Description copied from interface: ExternalTaskClientBuilder

Exposes the internal Apache HttpClientBuilder for custom client configurations.

Interceptors added via ExternalTaskClientBuilder.addInterceptor(ClientRequestInterceptor) are added as last in the ExternalTaskClientBuilder.build() method.

Specified by:

customizeHttpClient in interface ExternalTaskClientBuilder

Parameters:

httpClientConsumer - the parameter that accepts the HttpClientBuilder

Returns:

the builder

deserializationTypeValidator

public ExternalTaskClientBuilder deserializationTypeValidator(DeserializationTypeValidator deserializationTypeValidator)

Description copied from interface: ExternalTaskClientBuilder

Configures validation of the Java type that object variables are deserialized into, resolved from the (attacker-influenceable) objectTypeName variable metadata received from the engine. Not configured by default, i.e. by default no validation is performed and every previously working customer-defined DTO class keeps working unchanged.

Applications that want to restrict deserialization to a known set of DTO classes can supply their own DeserializationTypeValidator, or use the ready-to-use DefaultDeserializationTypeValidator allowlist implementation.

Note: not every built-in data format is able to honor this validator. In particular, native Java serialization (application/x-java-serialized-object) does not use objectTypeName for class selection at all and cannot be protected this way.

Specified by:

deserializationTypeValidator in interface ExternalTaskClientBuilder

Parameters:

deserializationTypeValidator - validates the Java type(s) object variables are deserialized into

Returns:

the builder

build

public ExternalTaskClient build()

Description copied from interface: ExternalTaskClientBuilder

Bootstraps the Camunda client

Specified by:

build in interface ExternalTaskClientBuilder

Returns:

the builder

initBaseUrl

protected void initBaseUrl()

sanitizeUrl

protected String sanitizeUrl(String url)

initWorkerId

protected void initWorkerId()

checkInterceptors

protected void checkInterceptors()

initObjectMapper

protected void initObjectMapper()

initVariableMappers

protected void initVariableMappers()

initEngineClient

protected void initEngineClient()

initTopicSubscriptionManager

protected void initTopicSubscriptionManager()

lookupDataFormats

protected Map<String,DataFormat> lookupDataFormats()

lookupCustomDataFormats

protected void lookupCustomDataFormats(Map<String,DataFormat> dataFormats)

lookupProvider

protected void lookupProvider(Map<String,DataFormat> dataFormats,
 DataFormatProvider provider)

applyConfigurators

protected void applyConfigurators(Map<String,DataFormat> dataFormats)

applyConfigurator

protected void applyConfigurator(Map<String,DataFormat> dataFormats,
 DataFormatConfigurator configurator)

checkHostname

public String checkHostname()

getHostname

public String getHostname()
                   throws UnknownHostException

Throws:

UnknownHostException

getBaseUrl

public String getBaseUrl()

getWorkerId

protected String getWorkerId()

getInterceptors

protected List<ClientRequestInterceptor> getInterceptors()

getMaxTasks

protected int getMaxTasks()

getAsyncResponseTimeout

protected Long getAsyncResponseTimeout()

getLockDuration

protected long getLockDuration()

isAutoFetchingEnabled

protected boolean isAutoFetchingEnabled()

getBackoffStrategy

protected BackoffStrategy getBackoffStrategy()

getDefaultSerializationFormat

public String getDefaultSerializationFormat()

getDateFormat

public String getDateFormat()

getObjectMapper

public com.fasterxml.jackson.databind.ObjectMapper getObjectMapper()

getValueMappers

public ValueMappers getValueMappers()

getTypedValues

public TypedValues getTypedValues()

getEngineClient

public EngineClient getEngineClient()