GraphInstance (telekom-workflow-engine 1.2.7 API)

All Known Implementing Classes:

GraphInstanceImpl
```
public interface GraphInstance
```
A GraphInstance represents an executing instance of a Graph.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`addToExecutionQueue(Token token)` Adds a token to the execution queue.
`void`	`addToHistory(String event)` Adds the given event into the instance's history log.
`void`	`addToken(Token token)` Adds a token to the graph instance.
`void`	`addWorkItem(GraphWorkItem workItem)` When a token execution reaches a wait state, it produces a `WorkItem` which describes the work that needs to be completed in order to continue the token's execution.
`List<Token>`	`getActiveChildTokens(Token parent)` `Token`s are created with a tree-like parent-child relation-ship.
`List<Token>`	`getActiveTokens()`
`GraphWorkItem`	`getActiveWorkItem(Token token)` A token can be associated with 0 or 1 active work items.
`Environment`	`getEnvironment()`
`Long`	`getExternalId()` A `GraphInstance` may be assigned an external id to associate it with externally persisted state, buisness data, etc.
`Token`	`getFirstFromExecutionQueue()` A `GraphInstance` keeps a queue of tokens for which the engine should attempt to proceed execution.
`Graph`	`getGraph()`
`String`	`getHistory()` Returns the instance's history log.
`List<Token>`	`getTokens()`
`List<GraphWorkItem>`	`getWorkItems()`
`boolean`	`isCompleted()` A `GraphInstance` is completed if it does not contain any active tokens.
`int`	`nextTokenId()` A `Token` has a graph instance specific id.
`void`	`removeFirstFromExecutionQueue()` Removes the head of the execution queue.

- Method Detail
  - getExternalId
```
Long getExternalId()
```
    A GraphInstance may be assigned an external id to associate it with externally persisted state, buisness data, etc.
    
    Returns:
    
    the graph instance's external id
  - getGraph
```
Graph getGraph()
```
    Returns:
    
    the graph being executed
  - getEnvironment
```
Environment getEnvironment()
```
    Returns:
    
    the graph instance's Environment
  - getTokens
```
List<Token> getTokens()
```
    Returns:
    
    the list of all tokens (both active and inactive) in the graph instance
  - getActiveTokens
```
List<Token> getActiveTokens()
```
    Returns:
    
    the list of all active tokens in the graph instance
  - getActiveChildTokens
```
List<Token> getActiveChildTokens(Token parent)
```
    Tokens are created with a tree-like parent-child relation-ship. Each token has exactly one parent and may have zero to many child tokens. Child tokens are mainly created at fork nodes which produce 1-N outgoing tokens. When a token is cancelled, all it's child tokens are cancelled as well.
    
    Returns:
    
    the list of all active child tokens of the given parent token
  - addToken
```
void addToken(Token token)
```
    Adds a token to the graph instance.
    
    Parameters:
    
    token - the token to be added
  - isCompleted
```
boolean isCompleted()
```
    A GraphInstance is completed if it does not contain any active tokens.
    
    Returns:
    
    true, if the graph instance is completed.
  - nextTokenId
```
int nextTokenId()
```
    A Token has a graph instance specific id. It is a graph instance's task to provide a sequence for such id numbers.
    
    Returns:
    
    a new token id, as used when creating a new token
  - addWorkItem
```
void addWorkItem(GraphWorkItem workItem)
```
    When a token execution reaches a wait state, it produces a WorkItem which describes the work that needs to be completed in order to continue the token's execution.
    This node is not intended to be called directly from a node's Node.execute(GraphEngine, Token) method. They should rather call methods such as GraphEngine.addSignalItem(GraphInstance, Token, String) which also notify GraphWorkItemEventListeners in addition to calling this method.
    
    Parameters:
    
    workItem - the work item to be added to the instance
  - getActiveWorkItem
```
GraphWorkItem getActiveWorkItem(Token token)
```
    A token can be associated with 0 or 1 active work items. A work item is considered active if its status is neither WorkItemStatus.COMPLETED nor WorkItemStatus.CANCELLED.
    
    Parameters:
    
    token - the token of which to find the active work item
    
    Returns:
    
    the active work item associated with the given token or null if no such work item exists
  - getWorkItems
```
List<GraphWorkItem> getWorkItems()
```
    Returns:
    
    a list of all work items (both active and inactive) in the graph instance
  - addToHistory
```
void addToHistory(String event)
```
    Adds the given event into the instance's history log.
    
    Parameters:
    
    event - information on an execution event
  - getHistory
```
String getHistory()
```
    Returns the instance's history log.
    
    Returns:
    
    the instance's history log.
  - getFirstFromExecutionQueue
```
Token getFirstFromExecutionQueue()
```
    A GraphInstance keeps a queue of tokens for which the engine should attempt to proceed execution. This method peeks the top of this queue, i.e. it returns the queue's head but does not remove it.
    
    Returns:
    
    the token to continue execution with or null if currently no token can be executed
  - addToExecutionQueue
```
void addToExecutionQueue(Token token)
```
    Adds a token to the execution queue.
    
    Parameters:
    
    token - the token to be added
  - removeFirstFromExecutionQueue
```
void removeFirstFromExecutionQueue()
```
    Removes the head of the execution queue.

Interface GraphInstance

Method Summary

Method Detail

getExternalId

getGraph

getEnvironment

getTokens

getActiveTokens

getActiveChildTokens

addToken

isCompleted

nextTokenId

addWorkItem

getActiveWorkItem

getWorkItems

addToHistory

getHistory

getFirstFromExecutionQueue

addToExecutionQueue

removeFirstFromExecutionQueue