Executes the contained tasks in separate threads, continuing once all are completed.

New behavior allows for the ant script to specify a maximum number of threads that will be executed in parallel. One should be very careful about using the waitFor task when specifying threadCount as it can cause deadlocks if the number of threads is too small or if one of the nested tasks fails to execute completely. The task selection algorithm will insure that the tasks listed before a task have started before that task is started, but it will not insure a successful completion of those tasks or that those tasks will finish first (i.e. it's a classic race condition).

Nested and Inner Type Summary

Modifier and Type	Class and Description
public static class	Parallel.TaskList Class which holds a list of tasks to execute
private class	Parallel.TaskRunnable thread that execs a task

Field Summary

Modifier and Type	Field and Description
private Parallel.TaskList	daemonTasks The daemon task list if any
private StringBuffer	exceptionMessage Accumulation of exceptions messages from all nested tasks
private boolean	failOnAny Indicates whether failure of any of the nested tasks should end execution
private Throwable	firstException The first exception encountered
private Integer	firstExitStatus The status of the first ExitStatusException.
private Location	firstLocation The location of the first exception
private Vector<Task>	nestedTasks Collection holding the nested tasks
private static final int	NUMBER_TRIES
private int	numExceptions Number of exceptions from nested tasks
private int	numThreads Total number of threads to run
private int	numThreadsPerProcessor Total number of threads per processor to run.
private final Object	semaphore Semaphore to notify of completed threads
private volatile boolean	stillRunning Indicates threads are still running and new threads can be issued
private boolean	timedOut Indicates that the execution timedout
private long	timeout The timeout period in milliseconds

Inherited from org.apache.tools.ant.Task:: target taskName taskType wrapper

Constructor Summary

Access	Constructor and Description
public	Parallel()

Method Summary

Modifier and Type	Method and Description
public void	addDaemons(Parallel.TaskList The tasks to be executed as daemon. daemonTasks) Add a group of daemon threads
public void	addTask(Task Nested task to be executed in parallel nestedTask) Implements org.apache.tools.ant.TaskContainer.addTask. Add a nested task to execute in parallel.
public void	execute() Overrides org.apache.tools.ant.Task.execute. Execute the parallel tasks
private void	killAll(Parallel.TaskRunnable[] The list of tasks that may currently be running. running) Doesn't do anything if all threads where already gone, else it tries to interrupt the threads 100 times.
private void	processExceptions(Parallel.TaskRunnable[] runnables)
public void	setFailOnAny(boolean if true any nested task failure causes parallel to complete. failOnAny) Control whether a failure in a nested task halts execution.
public void	setPollInterval(int New value of property pollInterval. pollInterval) Interval to poll for completed threads when threadCount or threadsPerProcessor is specified.
public void	setThreadCount(int total number of threads. numThreads) Statically determine the maximum number of tasks to execute simultaneously.
public void	setThreadsPerProcessor(int Number of threads to create per available processor. numThreadsPerProcessor) Dynamically generates the number of threads to execute based on the number of available processors (via `java.lang.Runtime.availableProcessors()`).
public void	setTimeout(long timeout in milliseconds. timeout) Sets the timeout on this set of tasks.
private void	spinThreads() Spin up required threads with a maximum number active at any given time.
private void	updateThreadCounts() Determine the number of threads based on the number of processors

Field Detail

daemonTasks	back to summary
private Parallel.TaskList daemonTasks The daemon task list if any

exceptionMessage	back to summary
private StringBuffer exceptionMessage Accumulation of exceptions messages from all nested tasks

failOnAny	back to summary
private boolean failOnAny Indicates whether failure of any of the nested tasks should end execution

firstException	back to summary
private Throwable firstException The first exception encountered

firstExitStatus	back to summary
private Integer firstExitStatus The status of the first ExitStatusException.

firstLocation	back to summary
private Location firstLocation The location of the first exception

nestedTasks	back to summary
private Vector<Task> nestedTasks Collection holding the nested tasks

NUMBER_TRIES	back to summary
private static final int NUMBER_TRIES

numExceptions	back to summary
private int numExceptions Number of exceptions from nested tasks

numThreads	back to summary
private int numThreads Total number of threads to run

numThreadsPerProcessor	back to summary
private int numThreadsPerProcessor Total number of threads per processor to run.

semaphore	back to summary
private final Object semaphore Semaphore to notify of completed threads

stillRunning	back to summary
private volatile boolean stillRunning Indicates threads are still running and new threads can be issued

timedOut	back to summary
private boolean timedOut Indicates that the execution timedout

timeout	back to summary
private long timeout The timeout period in milliseconds

Constructor Detail

Parallel	back to summary
public Parallel()

Method Detail

addDaemons	back to summary
public void addDaemons(Parallel.TaskList daemonTasks) Add a group of daemon threads Parameters daemonTasks:Parallel.TaskList The tasks to be executed as daemon.

addDaemons

back to summary

public void addDaemons(Parallel.TaskList daemonTasks)

Add a group of daemon threads

Parameters

daemonTasks:Parallel.TaskList: The tasks to be executed as daemon.

addTask	back to summary
public void addTask(Task nestedTask) Implements org.apache.tools.ant.TaskContainer.addTask. Add a nested task to execute in parallel. Parameters nestedTask:Task Nested task to be executed in parallel Annotations @Override

addTask

back to summary

public void addTask(Task nestedTask)

Implements org.apache.tools.ant.TaskContainer.addTask.

Add a nested task to execute in parallel.

Parameters

nestedTask:Task: Nested task to be executed in parallel

Annotations

@Override

execute	back to summary
public void execute() throws BuildException Overrides org.apache.tools.ant.Task.execute. Execute the parallel tasks Annotations @Override Exceptions BuildException: if any of the threads failed.

execute

back to summary

public void execute() throws BuildException

Overrides org.apache.tools.ant.Task.execute.

Execute the parallel tasks

Annotations

@Override

Exceptions

BuildException:: if any of the threads failed.

killAll	back to summary
private void killAll(Parallel.TaskRunnable[] running) Doesn't do anything if all threads where already gone, else it tries to interrupt the threads 100 times. Parameters running:Parallel.TaskRunnable[] The list of tasks that may currently be running.

killAll

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private void killAll(Parallel.TaskRunnable[] running)

Doesn't do anything if all threads where already gone, else it tries to interrupt the threads 100 times.

Parameters

running:Parallel.TaskRunnable[]: The list of tasks that may currently be running.

processExceptions	back to summary
private void processExceptions(Parallel.TaskRunnable[] runnables)

setFailOnAny	back to summary
public void setFailOnAny(boolean failOnAny) Control whether a failure in a nested task halts execution. Note that the task will complete but existing threads will continue to run - they are not stopped Parameters failOnAny:boolean if true any nested task failure causes parallel to complete.

setFailOnAny

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public void setFailOnAny(boolean failOnAny)

Control whether a failure in a nested task halts execution. Note that the task will complete but existing threads will continue to run - they are not stopped

Parameters

failOnAny:boolean: if true any nested task failure causes parallel to complete.

setPollInterval	back to summary
public void setPollInterval(int pollInterval) Interval to poll for completed threads when threadCount or threadsPerProcessor is specified. Integer in milliseconds.; optional Parameters pollInterval:int New value of property pollInterval.

setPollInterval

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public void setPollInterval(int pollInterval)

Interval to poll for completed threads when threadCount or threadsPerProcessor is specified. Integer in milliseconds.; optional

Parameters

pollInterval:int: New value of property pollInterval.

setThreadCount back to summary

setThreadCount	back to summary
public void setThreadCount(int numThreads) Statically determine the maximum number of tasks to execute simultaneously. If there are less tasks than threads then all will be executed at once, if there are more then only `threadCount` tasks will be executed at one time. If `threadsPerProcessor` is set then this value is ignored.; optional Parameters numThreads:int total number of threads.

public void setThreadCount(int numThreads)

Statically determine the maximum number of tasks to execute simultaneously. If there are less tasks than threads then all will be executed at once, if there are more then only threadCount tasks will be executed at one time. If threadsPerProcessor is set then this value is ignored.; optional

Parameters

numThreads:int: total number of threads.

setThreadsPerProcessor back to summary

setThreadsPerProcessor	back to summary
public void setThreadsPerProcessor(int numThreadsPerProcessor) Dynamically generates the number of threads to execute based on the number of available processors (via `java.lang.Runtime.availableProcessors()`). Will overwrite the value set in threadCount; optional Parameters numThreadsPerProcessor:int Number of threads to create per available processor.

public void setThreadsPerProcessor(int numThreadsPerProcessor)

Dynamically generates the number of threads to execute based on the number of available processors (via java.lang.Runtime.availableProcessors()). Will overwrite the value set in threadCount; optional

Parameters

numThreadsPerProcessor:int: Number of threads to create per available processor.

setTimeout	back to summary
public void setTimeout(long timeout) Sets the timeout on this set of tasks. If the timeout is reached before the other threads complete, the execution of this task completes with an exception. Note that existing threads continue to run. Parameters timeout:long timeout in milliseconds.

setTimeout

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public void setTimeout(long timeout)

Sets the timeout on this set of tasks. If the timeout is reached before the other threads complete, the execution of this task completes with an exception. Note that existing threads continue to run.

Parameters

timeout:long: timeout in milliseconds.

spinThreads	back to summary
private void spinThreads() throws BuildException Spin up required threads with a maximum number active at any given time. Exceptions BuildException: if any of the threads failed.

spinThreads

back to summary

private void spinThreads() throws BuildException

Spin up required threads with a maximum number active at any given time.

Exceptions

BuildException:: if any of the threads failed.

updateThreadCounts	back to summary
private void updateThreadCounts() Determine the number of threads based on the number of processors

org.apache.tools.ant.taskdefs back to summary

public Class Parallel.TaskList

Class Inheritance

extends Object
implements TaskContainer

java.lang.Object
org.apache.tools.ant.taskdefs.Parallel.TaskList

All Implemented Interfaces

org.apache.tools.ant.TaskContainer

Class which holds a list of tasks to execute

Field Summary

Modifier and Type	Field and Description
private List<Task>	tasks Collection holding the nested tasks

Constructor Summary

Access	Constructor and Description
public	TaskList()

Method Summary

Modifier and Type	Method and Description
public void	addTask(Task Nested task to be executed in parallel. must not be null. nestedTask) Implements org.apache.tools.ant.TaskContainer.addTask. Add a nested task to execute in parallel (asynchronously).

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

tasks	back to summary
private List<Task> tasks Collection holding the nested tasks

Constructor Detail

TaskList	back to summary
public TaskList()

Method Detail

addTask	back to summary
public void addTask(Task nestedTask) Implements org.apache.tools.ant.TaskContainer.addTask. Add a nested task to execute in parallel (asynchronously). Parameters nestedTask:Task Nested task to be executed in parallel. must not be null. Annotations @Override

addTask

back to summary

public void addTask(Task nestedTask)

Implements org.apache.tools.ant.TaskContainer.addTask.

Add a nested task to execute in parallel (asynchronously).

Parameters

nestedTask:Task: Nested task to be executed in parallel. must not be null.

Annotations

@Override

org.apache.tools.ant.taskdefs back to summary

private Class Parallel.TaskRunnable

Class Inheritance

extends Object
implements Runnable

java.lang.Object
org.apache.tools.ant.taskdefs.Parallel.TaskRunnable

All Implemented Interfaces

java.lang.Runnable

thread that execs a task

Field Summary

Modifier and Type	Field and Description
private Throwable	exception
private boolean	finished
private Task	task
private volatile Thread	thread

Constructor Summary

Access	Constructor and Description
pack-priv	TaskRunnable(Task the Task to be executed in a separate thread task) Construct a new TaskRunnable.

Method Summary

Modifier and Type	Method and Description
public Throwable	Returns: an exception or null for no exception/not yet finished getException() get any exception that got thrown during execution;
pack-priv void	interrupt()
pack-priv boolean	Returns: Returns true when the task is finished. isFinished() Provides the indicator that the task has been finished.
public void	run() Implements java.lang.Runnable.run. Executes the task within a thread and takes care about Exceptions raised within the task.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

exception	back to summary
private Throwable exception

finished	back to summary
private boolean finished

task	back to summary
private Task task

thread	back to summary
private volatile Thread thread

Constructor Detail

TaskRunnable	back to summary
pack-priv TaskRunnable(Task task) Construct a new TaskRunnable. Parameters task:Task the Task to be executed in a separate thread

TaskRunnable

back to summary

pack-priv TaskRunnable(Task task)

Construct a new TaskRunnable.

Parameters

task:Task: the Task to be executed in a separate thread

Method Detail

getException	back to summary
public Throwable getException() get any exception that got thrown during execution; Returns:Throwable an exception or null for no exception/not yet finished

getException

back to summary

public Throwable getException()

get any exception that got thrown during execution;

Returns:Throwable: an exception or null for no exception/not yet finished

interrupt	back to summary
pack-priv void interrupt()

isFinished	back to summary
pack-priv boolean isFinished() Provides the indicator that the task has been finished. Returns:boolean Returns true when the task is finished.

isFinished

back to summary

pack-priv boolean isFinished()

Provides the indicator that the task has been finished.

Returns:boolean: Returns true when the task is finished.

run	back to summary
public void run() Implements java.lang.Runnable.run. Executes the task within a thread and takes care about Exceptions raised within the task. Annotations @Override

run

back to summary

public void run()

Implements java.lang.Runnable.run.

Executes the task within a thread and takes care about Exceptions raised within the task.

Annotations

@Override