Class MergeExecutor

java.lang.Object

ai.nervemind.app.executor.MergeExecutor

All Implemented Interfaces:

NodeExecutor

@Component
public class MergeExecutor
extends Object
implements NodeExecutor

Executor for the "merge" node type - combines data from multiple input branches.

Handles synchronization of parallel workflow branches by collecting and combining data from multiple incoming edges. Essential for rejoining parallel execution paths created by ParallelExecutor or graph structure.

Node Parameters

Merge node configuration parameters

Parameter	Type	Default	Description
mode	String	"waitAll"	How to merge inputs (see modes below)
inputCount	Integer	2	Expected number of inputs (for waitAll mode)
timeout	Integer	300	Timeout in seconds for waiting
outputKey	String	"merged"	Key under which to store merged data
waitForAll	Boolean	true	If false, proceed with first input (for exclusive/conditional branches)

Merge Modes

• waitAll - Wait for all expected inputs before proceeding (uses CountDownLatch for synchronization)
• waitAny - Proceed as soon as any input arrives
• append - Append all inputs to a list
• merge - Deep merge all input objects (later inputs override earlier)
• passthrough - Pass through input directly without nesting. When waitForAll=false, proceeds with first input (ideal for IF/conditional branches)

Output Data

Output keys added by this executor

Key	Type	Description
[outputKey]	Map/List	Combined data based on mode
_inputCount	Integer	Number of inputs that were merged
_mergeMode	String	The mode used for merging

Thread Safety

Uses ConcurrentHashMap and CountDownLatch to handle concurrent input from multiple threads in parallel execution scenarios.

See Also:

• For spawning parallel branches

Constructor Summary

Constructors

Constructor	Description
MergeExecutor()	Default constructor.

Method Summary

Modifier and Type	Method	Description
Map<String,Object>	execute(ai.nervemind.common.domain.Node node, Map<String,Object> input, ExecutionService.ExecutionContext context)	Executes the business logic for this node type.
String	getNodeType()	Unique identifier for the node type this executor handles.

Methods inherited from class Object

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

Constructor Details

MergeExecutor

public MergeExecutor()

Default constructor.

Method Details

execute

public Map<String,Object> execute(ai.nervemind.common.domain.Node node,
 Map<String,Object> input,
 ExecutionService.ExecutionContext context)

Description copied from interface: NodeExecutor

Executes the business logic for this node type.

Specified by:

execute in interface NodeExecutor

Parameters:

node - The node definition containing parameters and configuration. Use Node.parameters() to access user settings.

input - Combined output from all upstream nodes that connected to this node. For simple flows, this contains the direct predecessor's output. For merge nodes, it contains combined data.

context - Verification context providing access to workflow-scoped services, logger, and execution metadata.

Returns:

A Map containing the results of this node's execution. Keys in this map become available variables for downstream nodes.
Note: Returning null is treated as an empty map.

getNodeType

public String getNodeType()

Description copied from interface: NodeExecutor

Unique identifier for the node type this executor handles. This must match the 'type' field in the JSON definition of the node.

Specified by:

getNodeType in interface NodeExecutor

Returns:

The unique type string (e.g., "httpRequest", "llmChat").