uk.ac.starlink.ttools.filter

Class StepFactory

java.lang.Object

uk.ac.starlink.ttools.filter.StepFactory

public class StepFactory
extends Object

Factory which can create ProcessingStep objects from strings which represent the filter specifications.

This is currently a singleton class.

Since:

16 Aug 2005

Author:

Mark Taylor (Starlink)

Method Summary

Modifier and Type	Method and Description
ProcessingStep	createStep(String line) Creates a processing filter from a line of text.
ProcessingStep[]	createSteps(String text) Creates an array of processing filters from an input string.
ObjectFactory<ProcessingFilter>	getFilterFactory() Returns the factory which can create filters from their nicknames.
static StepFactory	getInstance() Returns the singleton instance of this class.

Methods inherited from class java.lang.Object

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

Method Detail

getFilterFactory

public ObjectFactory<ProcessingFilter> getFilterFactory()

Returns the factory which can create filters from their nicknames.

Returns:

ProcessingFilter factory

createSteps

public ProcessingStep[] createSteps(String text)
                             throws TaskException

Creates an array of processing filters from an input string. The string may contain zero or more lines, separated by semicolons or newlines.

Parameters:

text - input string

Returns:

array of steps

Throws:

TaskException

createStep

public ProcessingStep createStep(String line)
                          throws TaskException

Creates a processing filter from a line of text. The general format for the line is <filter-name> <filter-args>

Parameters:

line - line of text representing filter commands

Returns:

processing step; may be null if line contains no tokens

Throws:

TaskException

getInstance

public static StepFactory getInstance()

Returns the singleton instance of this class.

Returns:

StepFactory instance