Class IntolerantThreadPoolExecutor<T>
- java.lang.Object
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- java.util.concurrent.AbstractExecutorService
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- java.util.concurrent.ThreadPoolExecutor
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- com.opencsv.bean.concurrent.IntolerantThreadPoolExecutor<T>
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- Type Parameters:
T
- The type of the object being created by the threads run
- All Implemented Interfaces:
java.util.concurrent.Executor
,java.util.concurrent.ExecutorService
,java.util.Spliterator<T>
- Direct Known Subclasses:
BeanExecutor
,LineExecutor
class IntolerantThreadPoolExecutor<T> extends java.util.concurrent.ThreadPoolExecutor implements java.util.Spliterator<T>
This ThreadPoolExecutor automatically shuts down on any failed thread.This is the historically established precedent for dealing with input errors in opencsv. This implementation expects all uncaught exceptions from its threads to be wrapped in a
RuntimeException
. The number of threads in the pool is fixed.It is not intended for this executor to be instantiated and receive jobs directly. There are function-specific derived classes for that purpose.
This executor adds significant logic to the basic idea of an
Executor
, and thus must be used differently from other executors. Usage follows this pattern:prepare()
- Submit tasks. This is not intended to be done directly to this class, but rather to one of the submission methods of the derived classes.
complete()
- The results are had by creating a
Stream
out of the executor itself. This is most easily done withStreamSupport.stream(Spliterator, boolean)
- Possibly
getCapturedExceptions()
The execution structure of this class is:
- The main thread (outside of this executor) parses input and passes it on to
- This executor, which performs a number of conversions in parallel and passes these results and any resultant errors to
- The accumulator, which creates an ordered list of the results.
The threads in the executor queue their results in a thread-safe queue, which should be O(1), minimizing wait time due to synchronization. The accumulator then removes items from the queue and inserts them into a sorted data structure, which is O(log n) on average and O(n) in the worst case. If the user has told us she doesn't need sorted data, the accumulator is not necessary, and thus is not started.
- Since:
- 4.0
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Nested Class Summary
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Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor
java.util.concurrent.ThreadPoolExecutor.AbortPolicy, java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy, java.util.concurrent.ThreadPoolExecutor.DiscardOldestPolicy, java.util.concurrent.ThreadPoolExecutor.DiscardPolicy
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Nested classes/interfaces inherited from interface java.util.Spliterator
java.util.Spliterator.OfDouble, java.util.Spliterator.OfInt, java.util.Spliterator.OfLong, java.util.Spliterator.OfPrimitive<T extends java.lang.Object,T_CONS extends java.lang.Object,T_SPLITR extends java.util.Spliterator.OfPrimitive<T,T_CONS,T_SPLITR>>
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Field Summary
Fields Modifier and Type Field Description protected AccumulateCsvResults<T>
accumulateThread
A separate thread that accumulates and orders results.protected java.util.Locale
errorLocale
The locale for error messages.protected java.util.SortedSet<java.lang.Long>
expectedRecords
A list of the ordinals of data records still to be expected by the accumulator.private boolean
orderedResults
Determines whether resulting data sets have to be in the same order as the input.private java.util.concurrent.ConcurrentNavigableMap<java.lang.Long,T>
resultantBeansMap
A sorted, concurrent map for the beans created.protected java.util.concurrent.BlockingQueue<OrderedObject<T>>
resultQueue
A queue of the beans created.private java.lang.Throwable
terminalException
The exception that caused this Executor to stop executing.private org.apache.commons.collections4.ListValuedMap<java.lang.Long,CsvException>
thrownExceptionsMap
A multi-valued map for any exceptions captured.protected java.util.concurrent.BlockingQueue<OrderedObject<CsvException>>
thrownExceptionsQueue
A queue of exceptions thrown by threads during processing.
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Constructor Summary
Constructors Constructor Description IntolerantThreadPoolExecutor(boolean orderedResults, java.util.Locale errorLocale)
Constructor for a thread pool executor that stops by itself as soon as any thread throws an exception.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
afterExecute(java.lang.Runnable r, java.lang.Throwable t)
Shuts the Executor down if the thread ended in an exception.private boolean
areMoreResultsAvailable()
Determines whether more conversion results can be expected.int
characteristics()
protected void
checkExceptions()
Checks whether exceptions are available that should halt processing.void
complete()
Sends a signal to the Executor that it should shut down once all threads have completed.long
estimateSize()
java.util.List<CsvException>
getCapturedExceptions()
Returns exceptions captured during the conversion process if the conversion process was set not to propagate these errors up the call stack.java.lang.Throwable
getTerminalException()
If an unrecoverable exception was thrown during processing, it can be retrieved here.private boolean
isConversionComplete()
void
prepare()
Prepares this Executor to receive jobs.java.util.List<java.lang.Runnable>
shutdownNow()
boolean
tryAdvance(java.util.function.Consumer<? super T> action)
java.util.Spliterator<T>
trySplit()
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Methods inherited from class java.util.concurrent.ThreadPoolExecutor
allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, beforeExecute, execute, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getQueue, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, remove, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, shutdown, terminated, toString
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Methods inherited from class java.util.concurrent.AbstractExecutorService
invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor, submit, submit, submit
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Field Detail
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resultQueue
protected final java.util.concurrent.BlockingQueue<OrderedObject<T>> resultQueue
A queue of the beans created.
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thrownExceptionsQueue
protected final java.util.concurrent.BlockingQueue<OrderedObject<CsvException>> thrownExceptionsQueue
A queue of exceptions thrown by threads during processing.
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resultantBeansMap
private java.util.concurrent.ConcurrentNavigableMap<java.lang.Long,T> resultantBeansMap
A sorted, concurrent map for the beans created.
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thrownExceptionsMap
private org.apache.commons.collections4.ListValuedMap<java.lang.Long,CsvException> thrownExceptionsMap
A multi-valued map for any exceptions captured.The multi-valued part is important because the same line can throw more than one exception.
All access to this variable must be synchronized.
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accumulateThread
protected AccumulateCsvResults<T> accumulateThread
A separate thread that accumulates and orders results.
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expectedRecords
protected final java.util.SortedSet<java.lang.Long> expectedRecords
A list of the ordinals of data records still to be expected by the accumulator.
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orderedResults
private final boolean orderedResults
Determines whether resulting data sets have to be in the same order as the input.
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errorLocale
protected final java.util.Locale errorLocale
The locale for error messages.
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terminalException
private java.lang.Throwable terminalException
The exception that caused this Executor to stop executing.
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Constructor Detail
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IntolerantThreadPoolExecutor
IntolerantThreadPoolExecutor(boolean orderedResults, java.util.Locale errorLocale)
Constructor for a thread pool executor that stops by itself as soon as any thread throws an exception. Threads never time out and the queue for inbound work is unbounded.- Parameters:
orderedResults
- Whether order should be preserved in the resultserrorLocale
- The errorLocale to use for error messages.
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Method Detail
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prepare
public void prepare()
Prepares this Executor to receive jobs.
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complete
public void complete() throws java.lang.InterruptedException
Sends a signal to the Executor that it should shut down once all threads have completed.- Throws:
java.lang.InterruptedException
- If the current thread is interrupted while waiting. Shouldn't be thrown, since the Executor waits indefinitely for all threads to end.java.util.concurrent.RejectedExecutionException
- If an exception during processing forced this Executor to shut down.
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getCapturedExceptions
public java.util.List<CsvException> getCapturedExceptions()
Returns exceptions captured during the conversion process if the conversion process was set not to propagate these errors up the call stack. The call is nondestructive.- Returns:
- All exceptions captured
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shutdownNow
public java.util.List<java.lang.Runnable> shutdownNow()
- Specified by:
shutdownNow
in interfacejava.util.concurrent.ExecutorService
- Overrides:
shutdownNow
in classjava.util.concurrent.ThreadPoolExecutor
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afterExecute
protected void afterExecute(java.lang.Runnable r, java.lang.Throwable t)
Shuts the Executor down if the thread ended in an exception.- Overrides:
afterExecute
in classjava.util.concurrent.ThreadPoolExecutor
- Parameters:
r
-t
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getTerminalException
public java.lang.Throwable getTerminalException()
If an unrecoverable exception was thrown during processing, it can be retrieved here.- Returns:
- The exception that halted one of the threads, which caused the executor to shut itself down
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checkExceptions
protected void checkExceptions()
Checks whether exceptions are available that should halt processing. This is the case with unrecoverable errors, such as parsing the input, or if exceptions in conversion should be thrown by request of the user.
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isConversionComplete
private boolean isConversionComplete()
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areMoreResultsAvailable
private boolean areMoreResultsAvailable()
Determines whether more conversion results can be expected. SinceSpliterator
s have no way of indicating that they don't have a result at the moment, but might in the future, we must ensure that every call totryAdvance(Consumer)
ortrySplit()
only returnsnull
if the entire conversion apparatus has shut down and all result queues are cleared. Thus, this method waits until either that is true, or there is truly at least one result that can be returned to users of theSpliterator
interface.- Returns:
false
if conversion is complete and no more results can ever be expected out of thisSpliterator
,true
otherwise. Iftrue
is returned, it is guaranteed that at least one result is available immediately to the caller.
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tryAdvance
public boolean tryAdvance(java.util.function.Consumer<? super T> action)
- Specified by:
tryAdvance
in interfacejava.util.Spliterator<T>
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trySplit
public java.util.Spliterator<T> trySplit()
- Specified by:
trySplit
in interfacejava.util.Spliterator<T>
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estimateSize
public long estimateSize()
- Specified by:
estimateSize
in interfacejava.util.Spliterator<T>
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characteristics
public int characteristics()
- Specified by:
characteristics
in interfacejava.util.Spliterator<T>
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