TaskExecutor (Lucene 9.9.2 core API)

java.lang.Object
- org.apache.lucene.search.TaskExecutor

```
public final class TaskExecutor
extends Object
```
Executor wrapper responsible for the execution of concurrent tasks. Used to parallelize search across segments as well as query rewrite in some cases. Exposes a single invokeAll(Collection) method that takes a collection of Callables and executes them concurrently/ Once all tasks are submitted to the executor, it blocks and wait for all tasks to be completed, and then returns a list with the obtained results. Ensures that the underlying executor is only used for top-level invokeAll(Collection) calls, and not for potential invokeAll(Collection) calls made from one of the tasks. This is to prevent deadlock with certain types of pool based executors (e.g. ThreadPoolExecutor).

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary

Constructors
Constructor Description

TaskExecutor(Executor executor)
Creates a TaskExecutor instance

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`<T> List<T>`	`invokeAll(Collection<Callable<T>> callables)`	Execute all the callables provided as an argument, wait for them to complete and return the obtained results.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - TaskExecutor
```
public TaskExecutor(Executor executor)
```
    Creates a TaskExecutor instance
    
    Parameters:
    
    executor - the executor to be used for running tasks concurrently
- Method Detail
  - invokeAll
```
public <T> List<T> invokeAll(Collection<Callable<T>> callables)
                      throws IOException
```
    Execute all the callables provided as an argument, wait for them to complete and return the obtained results. If an exception is thrown by more than one callable, the subsequent ones will be added as suppressed exceptions to the first one that was caught.
    
    Type Parameters:
    
    T - the return type of the task execution
    
    Parameters:
    
    callables - the callables to execute
    
    Returns:
    
    a list containing the results from the tasks execution
    
    Throws:
    
    IOException
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object