All Known Implementing Classes:

HistoryServiceImpl
```
@Internal
public interface HistoryService
```
Service exposing information about ongoing and past process instances. This is different from the runtime information in the sense that this runtime information only contains the actual runtime state at any given moment and it is optimized for runtime process execution performance. The history information is optimized for easy querying and remains permanent in the persistent storage.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`HistoricActivityInstanceQuery`	`createHistoricActivityInstanceQuery()`	Creates a new programmatic query to search for `HistoricActivityInstance`s.
`HistoricDetailQuery`	`createHistoricDetailQuery()`	Creates a new programmatic query to search for `HistoricDetail`s.
`HistoricProcessInstanceQuery`	`createHistoricProcessInstanceQuery()`	Creates a new programmatic query to search for `HistoricProcessInstance`s.
`HistoricTaskInstanceQuery`	`createHistoricTaskInstanceQuery()`	Creates a new programmatic query to search for `HistoricTaskInstance`s.
`HistoricVariableInstanceQuery`	`createHistoricVariableInstanceQuery()`	Creates a new programmatic query to search for `HistoricVariableInstance`s.
`NativeHistoricActivityInstanceQuery`	`createNativeHistoricActivityInstanceQuery()`	creates a native query to search for `HistoricActivityInstance`s via SQL
`NativeHistoricDetailQuery`	`createNativeHistoricDetailQuery()`	Returns a new `NativeQuery` for process definitions.
`NativeHistoricProcessInstanceQuery`	`createNativeHistoricProcessInstanceQuery()`	creates a native query to search for `HistoricProcessInstance`s via SQL
`NativeHistoricTaskInstanceQuery`	`createNativeHistoricTaskInstanceQuery()`	creates a native query to search for `HistoricTaskInstance`s via SQL
`NativeHistoricVariableInstanceQuery`	`createNativeHistoricVariableInstanceQuery()`	Returns a new `NativeQuery` for process definitions.
`ProcessInstanceHistoryLogQuery`	`createProcessInstanceHistoryLogQuery(java.lang.String processInstanceId)`	Allows to retrieve the `ProcessInstanceHistoryLog` for one process instance.
`void`	`deleteHistoricProcessInstance(java.lang.String processInstanceId)`	Deletes historic process instance.
`void`	`deleteHistoricTaskInstance(java.lang.String taskId)`	Deletes historic task instance.
`java.util.List<HistoricIdentityLink>`	`getHistoricIdentityLinksForProcessInstance(java.lang.String processInstanceId)`	Retrieves the `HistoricIdentityLink`s associated with the given process instance.
`java.util.List<HistoricIdentityLink>`	`getHistoricIdentityLinksForTask(java.lang.String taskId)`	Retrieves the `HistoricIdentityLink`s associated with the given task.

- Method Detail
  - createHistoricProcessInstanceQuery
```
HistoricProcessInstanceQuery createHistoricProcessInstanceQuery()
```
    Creates a new programmatic query to search for HistoricProcessInstances.
  - createHistoricActivityInstanceQuery
```
HistoricActivityInstanceQuery createHistoricActivityInstanceQuery()
```
    Creates a new programmatic query to search for HistoricActivityInstances.
  - createHistoricTaskInstanceQuery
```
HistoricTaskInstanceQuery createHistoricTaskInstanceQuery()
```
    Creates a new programmatic query to search for HistoricTaskInstances.
  - createHistoricDetailQuery
```
HistoricDetailQuery createHistoricDetailQuery()
```
    Creates a new programmatic query to search for HistoricDetails.
  - createNativeHistoricDetailQuery
```
NativeHistoricDetailQuery createNativeHistoricDetailQuery()
```
    Returns a new NativeQuery for process definitions.
  - createHistoricVariableInstanceQuery
```
HistoricVariableInstanceQuery createHistoricVariableInstanceQuery()
```
    Creates a new programmatic query to search for HistoricVariableInstances.
  - createNativeHistoricVariableInstanceQuery
```
NativeHistoricVariableInstanceQuery createNativeHistoricVariableInstanceQuery()
```
    Returns a new NativeQuery for process definitions.
  - deleteHistoricTaskInstance
```
void deleteHistoricTaskInstance(java.lang.String taskId)
```
    Deletes historic task instance. This might be useful for tasks that are dynamically created and then completed. If the historic task instance doesn't exist, no exception is thrown and the method returns normal.
  - deleteHistoricProcessInstance
```
void deleteHistoricProcessInstance(java.lang.String processInstanceId)
```
    Deletes historic process instance. All historic activities, historic task and historic details (variable updates, form properties) are deleted as well.
  - createNativeHistoricProcessInstanceQuery
```
NativeHistoricProcessInstanceQuery createNativeHistoricProcessInstanceQuery()
```
    creates a native query to search for HistoricProcessInstances via SQL
  - createNativeHistoricTaskInstanceQuery
```
NativeHistoricTaskInstanceQuery createNativeHistoricTaskInstanceQuery()
```
    creates a native query to search for HistoricTaskInstances via SQL
  - createNativeHistoricActivityInstanceQuery
```
NativeHistoricActivityInstanceQuery createNativeHistoricActivityInstanceQuery()
```
    creates a native query to search for HistoricActivityInstances via SQL
  - getHistoricIdentityLinksForTask
```
java.util.List<HistoricIdentityLink> getHistoricIdentityLinksForTask(java.lang.String taskId)
```
    Retrieves the HistoricIdentityLinks associated with the given task. Such an IdentityLink informs how a certain identity (eg. group or user) is associated with a certain task (eg. as candidate, assignee, etc.), even if the task is completed as opposed to IdentityLinks which only exist for active tasks.
  - getHistoricIdentityLinksForProcessInstance
```
java.util.List<HistoricIdentityLink> getHistoricIdentityLinksForProcessInstance(java.lang.String processInstanceId)
```
    Retrieves the HistoricIdentityLinks associated with the given process instance. Such an IdentityLink informs how a certain identity (eg. group or user) is associated with a certain process instance, even if the instance is completed as opposed to IdentityLinks which only exist for active instances.
  - createProcessInstanceHistoryLogQuery
```
ProcessInstanceHistoryLogQuery createProcessInstanceHistoryLogQuery(java.lang.String processInstanceId)
```
    Allows to retrieve the ProcessInstanceHistoryLog for one process instance.

Interface HistoryService

Method Summary

Method Detail

createHistoricProcessInstanceQuery

createHistoricActivityInstanceQuery

createHistoricTaskInstanceQuery

createHistoricDetailQuery

createNativeHistoricDetailQuery

createHistoricVariableInstanceQuery

createNativeHistoricVariableInstanceQuery

deleteHistoricTaskInstance

deleteHistoricProcessInstance

createNativeHistoricProcessInstanceQuery

createNativeHistoricTaskInstanceQuery

createNativeHistoricActivityInstanceQuery

getHistoricIdentityLinksForTask

getHistoricIdentityLinksForProcessInstance

createProcessInstanceHistoryLogQuery