uk.ac.starlink.ttools.task

Class MultiOutputTask

java.lang.Object

uk.ac.starlink.ttools.task.MultiOutputTask

All Implemented Interfaces:

Task

Direct Known Subclasses:

TableMultiCopy

public abstract class MultiOutputTask
extends Object
implements Task

Task which writes multiple tables to a single output file. Concrete subclasses must implement the createTableSequence(uk.ac.starlink.task.Environment) method.

Since:

6 Jul 2010

Author:

Mark Taylor

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MultiOutputTask(String purpose) Constructor.

Method Summary

Modifier and Type	Method and Description
Executable	createExecutable(Environment env) Creates an executable object which will do the work of this task in the given Environment.
protected abstract TableSequence	createTableSequence(Environment env) Interrogates the environment to produce a sequence of tables which will be written as the output of this task.
static TableSequence	createTableSequence(InputTableSpec[] inSpecs) Constructs a table sequence based on an array of input table specifications.
protected List<Parameter<?>>	getParameterList() Returns the parameter list for this task; it may be modified.
Parameter<?>[]	getParameters() Returns the list of parameters which may be used by this task.
String	getPurpose() Returns a short (one-line) description of the purpose of this task.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiOutputTask

protected MultiOutputTask(String purpose)

Constructor.

Parameters:

purpose - task purpose

Method Detail

getPurpose

public String getPurpose()

Description copied from interface: Task

Returns a short (one-line) description of the purpose of this task.

Specified by:

getPurpose in interface Task

Returns:

plain text description of this task's purpose

getParameters

public Parameter<?>[] getParameters()

Description copied from interface: Task

Returns the list of parameters which may be used by this task.

Specified by:

getParameters in interface Task

Returns:

an array of the Parameter objects this task may request values for during its invocation

getParameterList

protected List<Parameter<?>> getParameterList()

Returns the parameter list for this task; it may be modified.

Returns:

parameter list

createTableSequence

protected abstract TableSequence createTableSequence(Environment env)
                                              throws TaskException

Interrogates the environment to produce a sequence of tables which will be written as the output of this task.

Parameters:

env - execution environment

Returns:

sequence of tables to write

Throws:

TaskException

createExecutable

public Executable createExecutable(Environment env)
                            throws TaskException

Description copied from interface: Task

Creates an executable object which will do the work of this task in the given Environment. This method should do all of the parameter processing and prepare an object which just executes. The idea is that any communication with the user related to the supplied parameter values can be done before the task starts to execute in earnest. Consequently, the returned Executable object ought not to make any reference to env, though this is not absolutely prohibited.

Specified by:

createExecutable in interface Task

Parameters:

env - the environment in which the task will operate

Throws:

TaskException - if no executable can be created; this should usually be a UsageException or some subclass

createTableSequence

public static TableSequence createTableSequence(InputTableSpec[] inSpecs)
                                         throws TaskException

Constructs a table sequence based on an array of input table specifications.

Parameters:

inSpecs - array of input tables

Throws:

TaskException