org.scijava.plugin

Annotation Type Parameter

@Retention(value=RUNTIME)
@Target(value=FIELD)
public @interface Parameter

An annotation for indicating a field is an input or output parameter. This annotation is a useful way for plugins to declare their inputs and outputs simply.

Author:

Johannes Schindelin, Grant Harris, Curtis Rueden

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
Attr[]	attrs A list of additional attributes which can be used to extend this annotation beyond its built-in capabilities.
boolean	autoFill Defines whether the parameter value should be filled programmatically, if possible.
String	callback Defines a function that is called whenever this parameter changes.
String[]	choices Defines the list of possible values (multiple choice text fields only).
int	columns Defines the width of the input field in characters (text field parameters only).
String	description Defines a description for the parameter.
String	initializer Defines a function that is called to initialize the parameter.
String	label Defines a label for the parameter.
String	max Defines the maximum allowed value (numeric parameters only).
String	min Defines the minimum allowed value (numeric parameters only).
boolean	persist Defines whether to remember the most recent value of the parameter.
String	persistKey Defines a key to use for saving the value persistently.
boolean	required Defines whether the parameter value must be non-null.
String	stepSize Defines the step size to use (numeric parameters only).
String	style Defines the preferred widget style.
ItemIO	type Defines the input/output type of the parameter.
ItemVisibility	visibility Defines the "visibility" of the parameter.

Element Detail

label

public abstract String label

Defines a label for the parameter.

Default:

""

description

public abstract String description

Defines a description for the parameter.

Default:

""

type

public abstract ItemIO type

Defines the input/output type of the parameter.

Choices are:

• INPUT: parameter is an input for the plugin.
• OUTPUT: parameter is an output for the plugin.
• BOTH: parameter is both and input and an output for the plugin. This type is used to indicate an object that is mutated somehow during execution.

Default:

org.scijava.ItemIO.INPUT

visibility

public abstract ItemVisibility visibility

Defines the "visibility" of the parameter.

Choices are:

• NORMAL: parameter is included in the history for purposes of data provenance, and included as a parameter when recording scripts.
• TRANSIENT: parameter is excluded from the history for the purposes of data provenance, but still included as a parameter when recording scripts.
• INVISIBLE: parameter is excluded from the history for the purposes of data provenance, and also excluded as a parameter when recording scripts. This option should only be used for parameters with no effect on the final output, such as a "verbose" flag.
• MESSAGE: parameter value is intended as a message only, not editable by the user nor included as an input or output parameter.

Default:

org.scijava.ItemVisibility.NORMAL

autoFill

public abstract boolean autoFill

Defines whether the parameter value should be filled programmatically, if possible.

Default:

true

required

public abstract boolean required

Defines whether the parameter value must be non-null.

Default:

true

persist

public abstract boolean persist

Defines whether to remember the most recent value of the parameter.

Default:

true

persistKey

public abstract String persistKey

Defines a key to use for saving the value persistently.

Default:

""

initializer

public abstract String initializer

Defines a function that is called to initialize the parameter.

Default:

""

callback

public abstract String callback

Defines a function that is called whenever this parameter changes.

This mechanism enables interdependent parameters of various types. For example, two int parameters "width" and "height" could update each other when another boolean "Preserve aspect ratio" flag is set.

Default:

""

style

public abstract String style

Defines the preferred widget style.

We do not use an enum because the styles need to be extensible. And we cannot use an interface-driven extensible enum pattern, because interfaces cannot be used as attributes within a Java annotation interface. So we fall back to strings!

Default:

""

min

public abstract String min

Defines the minimum allowed value (numeric parameters only).

Default:

""

max

public abstract String max

Defines the maximum allowed value (numeric parameters only).

Default:

""

stepSize

public abstract String stepSize

Defines the step size to use (numeric parameters only).

Default:

""

columns

public abstract int columns

Defines the width of the input field in characters (text field parameters only).

Default:

6

choices

public abstract String[] choices

Defines the list of possible values (multiple choice text fields only).

Default:

{}

attrs

public abstract Attr[] attrs

A list of additional attributes which can be used to extend this annotation beyond its built-in capabilities.

Default:

{}