backtype.storm.task

Class TopologyContext

java.lang.Object

backtype.storm.task.GeneralTopologyContext

backtype.storm.task.WorkerTopologyContext

backtype.storm.task.TopologyContext

All Implemented Interfaces:

IMetricsContext, org.json.simple.JSONAware

public class TopologyContext
extends WorkerTopologyContext
implements IMetricsContext

A TopologyContext is given to bolts and spouts in their "prepare" and "open" methods, respectively. This object provides information about the component's place within the topology, such as task ids, inputs and outputs, etc.

The TopologyContext is also used to declare ISubscribedState objects to synchronize state with StateSpouts this object is subscribed to.

Field Summary

Fields inherited from class backtype.storm.task.WorkerTopologyContext

SHARED_EXECUTOR

Fields inherited from class backtype.storm.task.GeneralTopologyContext

_stormConf

Constructor Summary

Constructors

Constructor and Description

TopologyContext(StormTopology topology, Map stormConf, Map<Integer,String> taskToComponent, Map<String,List<Integer>> componentToSortedTasks, Map<String,Map<String,Fields>> componentToStreamToFields, String stormId, String codeDir, String pidDir, Integer taskId, Integer workerPort, List<Integer> workerTasks, Map<String,Object> defaultResources, Map<String,Object> userResources, Map<String,Object> executorData, Map registeredMetrics, clojure.lang.Atom openOrPrepareWasCalled)

Method Summary

Methods

Modifier and Type	Method and Description
void	addTaskHook(ITaskHook hook)
Object	getExecutorData(String name)
Collection<ITaskHook>	getHooks()
IMetric	getRegisteredMetricByName(String name) Get component's metric from registered metrics by name.
Object	getTaskData(String name)
String	getThisComponentId() Gets the component id for this task.
Fields	getThisOutputFields(String streamId) Gets the declared output fields for the specified stream id for the component this task is a part of.
Map<String,List<String>>	getThisOutputFieldsForStreams() Gets the declared output fields for the specified stream id for the component this task is a part of.
Map<GlobalStreamId,Grouping>	getThisSources() Gets the declared inputs to this component.
Set<String>	getThisStreams() Gets the set of streams declared for the component of this task.
Map<String,Map<String,Grouping>>	getThisTargets() Gets information about who is consuming the outputs of this component, and how.
int	getThisTaskId() Gets the task id of this task.
int	getThisTaskIndex() Gets the index of this task id in getComponentTasks(getThisComponentId()).
CombinedMetric	registerMetric(String name, ICombiner combiner, int timeBucketSizeInSecs)
ReducedMetric	registerMetric(String name, IReducer reducer, int timeBucketSizeInSecs)
<T extends IMetric> T	registerMetric(String name, T metric, int timeBucketSizeInSecs)
<T extends ISubscribedState> T	setAllSubscribedState(T obj) All state from all subscribed state spouts streams will be synced with the provided object.
void	setExecutorData(String name, Object data)
<T extends ISubscribedState> T	setSubscribedState(String componentId, String streamId, T obj) Synchronizes the specified stream from the specified state spout component id with the provided ISubscribedState object.
<T extends ISubscribedState> T	setSubscribedState(String componentId, T obj) Synchronizes the default stream from the specified state spout component id with the provided ISubscribedState object.
void	setTaskData(String name, Object data)
String	toJSONString()

Methods inherited from class backtype.storm.task.WorkerTopologyContext

getCodeDir, getPIDDir, getResource, getSharedExecutor, getThisWorkerPort, getThisWorkerTasks

Methods inherited from class backtype.storm.task.GeneralTopologyContext

getComponentCommon, getComponentId, getComponentIds, getComponentOutputFields, getComponentOutputFields, getComponentStreams, getComponentTasks, getRawTopology, getSources, getStormId, getTargets, getTaskToComponent, maxTopologyMessageTimeout

Methods inherited from class java.lang.Object

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

Constructor Detail

TopologyContext

public TopologyContext(StormTopology topology,
               Map stormConf,
               Map<Integer,String> taskToComponent,
               Map<String,List<Integer>> componentToSortedTasks,
               Map<String,Map<String,Fields>> componentToStreamToFields,
               String stormId,
               String codeDir,
               String pidDir,
               Integer taskId,
               Integer workerPort,
               List<Integer> workerTasks,
               Map<String,Object> defaultResources,
               Map<String,Object> userResources,
               Map<String,Object> executorData,
               Map registeredMetrics,
               clojure.lang.Atom openOrPrepareWasCalled)

Method Detail

setAllSubscribedState

public <T extends ISubscribedState> T setAllSubscribedState(T obj)

All state from all subscribed state spouts streams will be synced with the provided object.

It is recommended that your ISubscribedState object is kept as an instance variable of this object. The recommended usage of this method is as follows:

_myState = context.setAllSubscribedState(new MyState());

Parameters:

obj - Provided ISubscribedState implementation

Returns:

Returns the ISubscribedState object provided

setSubscribedState

public <T extends ISubscribedState> T setSubscribedState(String componentId,
                                                T obj)

Synchronizes the default stream from the specified state spout component id with the provided ISubscribedState object.

The recommended usage of this method is as follows:

_myState = context.setSubscribedState(componentId, new MyState());

Parameters:

componentId - the id of the StateSpout component to subscribe to

obj - Provided ISubscribedState implementation

Returns:

Returns the ISubscribedState object provided

setSubscribedState

public <T extends ISubscribedState> T setSubscribedState(String componentId,
                                                String streamId,
                                                T obj)

Synchronizes the specified stream from the specified state spout component id with the provided ISubscribedState object.

The recommended usage of this method is as follows:

_myState = context.setSubscribedState(componentId, streamId, new MyState());

Parameters:

componentId - the id of the StateSpout component to subscribe to

streamId - the stream to subscribe to

obj - Provided ISubscribedState implementation

Returns:

Returns the ISubscribedState object provided

getThisTaskId

public int getThisTaskId()

Gets the task id of this task.

Returns:

the task id

getThisComponentId

public String getThisComponentId()

Gets the component id for this task. The component id maps to a component id specified for a Spout or Bolt in the topology definition.

Returns:

getThisOutputFields

public Fields getThisOutputFields(String streamId)

Gets the declared output fields for the specified stream id for the component this task is a part of.

getThisOutputFieldsForStreams

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

Gets the declared output fields for the specified stream id for the component this task is a part of.

getThisStreams

public Set<String> getThisStreams()

Gets the set of streams declared for the component of this task.

getThisTaskIndex

public int getThisTaskIndex()

Gets the index of this task id in getComponentTasks(getThisComponentId()). An example use case for this method is determining which task accesses which resource in a distributed resource to ensure an even distribution.

getThisSources

public Map<GlobalStreamId,Grouping> getThisSources()

Gets the declared inputs to this component.

Returns:

A map from subscribed component/stream to the grouping subscribed with.

getThisTargets

public Map<String,Map<String,Grouping>> getThisTargets()

Gets information about who is consuming the outputs of this component, and how.

Returns:

Map from stream id to component id to the Grouping used.

setTaskData

public void setTaskData(String name,
               Object data)

getTaskData

public Object getTaskData(String name)

setExecutorData

public void setExecutorData(String name,
                   Object data)

getExecutorData

public Object getExecutorData(String name)

addTaskHook

public void addTaskHook(ITaskHook hook)

getHooks

public Collection<ITaskHook> getHooks()

toJSONString

public String toJSONString()

Specified by:

toJSONString in interface org.json.simple.JSONAware

Overrides:

toJSONString in class GeneralTopologyContext

registerMetric

public <T extends IMetric> T registerMetric(String name,
                                   T metric,
                                   int timeBucketSizeInSecs)

Specified by:

registerMetric in interface IMetricsContext

getRegisteredMetricByName

public IMetric getRegisteredMetricByName(String name)

Get component's metric from registered metrics by name. Notice: Normally, one component can only register one metric name once. But now registerMetric has a bug(https://issues.apache.org/jira/browse/STORM-254) cause the same metric name can register twice. So we just return the first metric we meet.

registerMetric

public ReducedMetric registerMetric(String name,
                           IReducer reducer,
                           int timeBucketSizeInSecs)

Specified by:

registerMetric in interface IMetricsContext

registerMetric

public CombinedMetric registerMetric(String name,
                            ICombiner combiner,
                            int timeBucketSizeInSecs)

Specified by:

registerMetric in interface IMetricsContext