Class Parallel

java.lang.Object

org.apache.tools.ant.ProjectComponent

org.apache.tools.ant.Task

org.apache.tools.ant.taskdefs.Parallel

All Implemented Interfaces:

Cloneable, TaskContainer

public class Parallel
extends Task
implements TaskContainer

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).

Since:

Ant 1.4

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Parallel.TaskList	Class which holds a list of tasks to execute

Field Summary

Fields inherited from class Task

target, taskName, taskType, wrapper

Modifier and Type	Field	Description
protected Target	target	Deprecated. since 1.6.x.
protected String	taskName	Deprecated. since 1.6.x.
protected String	taskType	Deprecated. since 1.6.x.
protected RuntimeConfigurable	wrapper	Deprecated. since 1.6.x.

Fields inherited from class ProjectComponent

description, location, project

Modifier and Type	Field	Description
protected String	description	Deprecated. since 1.6.x.
protected Location	location	Deprecated. since 1.6.x.
protected Project	project	Deprecated. since 1.6.x.

Constructor Summary

Constructors

Constructor	Description
Parallel()

Method Summary

Modifier and Type	Method	Description
void	addDaemons(Parallel.TaskList daemonTasks)	Add a group of daemon threads
void	addTask(Task nestedTask)	Add a nested task to execute in parallel.
void	execute()	Execute the parallel tasks
void	setFailOnAny(boolean failOnAny)	Control whether a failure in a nested task halts execution.
void	setPollInterval(int pollInterval)	Interval to poll for completed threads when threadCount or threadsPerProcessor is specified.
void	setThreadCount(int numThreads)	Statically determine the maximum number of tasks to execute simultaneously.
void	setThreadsPerProcessor(int numThreadsPerProcessor)	Dynamically generates the number of threads to execute based on the number of available processors (via java.lang.Runtime.availableProcessors()).
void	setTimeout(long timeout)	Sets the timeout on this set of tasks.

Methods inherited from class Task

bindToOwner, getOwningTarget, getRuntimeConfigurableWrapper, getTaskName, getTaskType, getWrapper, handleErrorFlush, handleErrorOutput, handleFlush, handleInput, handleOutput, init, isInvalid, log, log, log, log, maybeConfigure, perform, reconfigure, setOwningTarget, setRuntimeConfigurableWrapper, setTaskName, setTaskType

Modifier and Type	Method	Description
final void	bindToOwner(Task owner)	Bind a task to another; use this when configuring a newly created task to do work on behalf of another.
Target	getOwningTarget()	Returns the container target of this task.
RuntimeConfigurable	getRuntimeConfigurableWrapper()	Returns the wrapper used for runtime configuration.
String	getTaskName()	Returns the name to use in logging messages.
String	getTaskType()	Return the type of task.
protected RuntimeConfigurable	getWrapper()	Return the runtime configurable structure for this task.
protected void	handleErrorFlush(String output)	Handles an error line by logging it with the WARN priority.
protected void	handleErrorOutput(String output)	Handles an error output by logging it with the WARN priority.
protected void	handleFlush(String output)	Handles output by logging it with the INFO priority.
protected int	handleInput(byte[] buffer, int offset, int length)	Handle an input request by this task.
protected void	handleOutput(String output)	Handles output by logging it with the INFO priority.
void	init()	Called by the project to let the task initialize properly.
protected final boolean	isInvalid()	Has this task been marked invalid?
void	log(String msg)	Logs a message with the default (INFO) priority.
void	log(String msg, int msgLevel)	Logs a message with the given priority.
void	log(String msg, Throwable t, int msgLevel)	Logs a message with the given priority.
void	log(Throwable t, int msgLevel)	Logs a message with the given priority.
void	maybeConfigure()	Configures this task - if it hasn't been done already.
final void	perform()	Performs this task if it's still valid, or gets a replacement version and performs that otherwise.
void	reconfigure()	Force the task to be reconfigured from its RuntimeConfigurable.
void	setOwningTarget(Target target)	Sets the target container of this task.
void	setRuntimeConfigurableWrapper(RuntimeConfigurable wrapper)	Sets the wrapper to be used for runtime configuration.
void	setTaskName(String name)	Sets the name to use in logging messages.
void	setTaskType(String type)	Sets the name with which the task has been invoked.

Methods inherited from class ProjectComponent

clone, getDescription, getLocation, getProject, setDescription, setLocation, setProject

Modifier and Type	Method	Description
Object	clone()
String	getDescription()	Returns the description of the current action.
Location	getLocation()	Returns the file/location where this task was defined.
Project	getProject()	Returns the project to which this component belongs.
void	setDescription(String desc)	Sets a description of the current action.
void	setLocation(Location location)	Sets the file/location where this task was defined.
void	setProject(Project project)	Sets the project object of this component.

Methods inherited from class Object

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

Constructor Details

Parallel

public Parallel()

Method Details

addDaemons

public void addDaemons(Parallel.TaskList daemonTasks)

Add a group of daemon threads

Parameters:

daemonTasks - The tasks to be executed as daemon.

setPollInterval

public void setPollInterval(int pollInterval)

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

Parameters:

pollInterval - New value of property pollInterval.

setFailOnAny

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 - if true any nested task failure causes parallel to complete.

addTask

public void addTask(Task nestedTask)

Add a nested task to execute in parallel.

Specified by:

addTask in interface TaskContainer

Parameters:

nestedTask - Nested task to be executed in parallel

setThreadsPerProcessor

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 - Number of threads to create per available processor.

setThreadCount

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 - total number of threads.

setTimeout

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 - timeout in milliseconds.

execute

public void execute()
             throws BuildException

Execute the parallel tasks

Overrides:

execute in class Task

Throws:

BuildException - if any of the threads failed.