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org.apache.tools.ant.taskdefs

Class Parallel

  • All Implemented Interfaces:
    java.lang.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

    • Constructor Detail

      • Parallel

        public Parallel()

    • Method Detail

      • 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.
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