Support widget groups to resolve #310

src/main/java/org/scijava/ItemVisibility.java

@@ -61,6 +61,14 @@ public enum ItemVisibility {
 	 * intended as a message to the user (e.g., in the input harvester panel)
 	 * rather than an actual parameter to the module execution.
 	 */
-	MESSAGE
-
+	MESSAGE,
+
+	/**
+	 * Indicates that the item's value defines the name of a widget group
+	 * (e.g., in the input harvester panel) rather than an actual parameter 
+	 * to the module execution. Widget groups organize related input widgets. 
+	 * Group members are added to a group by providing a group parameter annotation 
+	 * having the common group name.
+	 */
+	GROUP
 }

src/main/java/org/scijava/command/CommandModuleItem.java

@@ -134,6 +134,16 @@ public String getCallback() {
 	public String getWidgetStyle() {
 		return getParameter().style();
 	}
+
+	@Override
+	public String getWidgetGroup() {
+		return getParameter().group();
+	}
+
+	@Override
+	public boolean isExpanded() {
+		return getParameter().expanded();
+	}
 
 	@Override
 	public T getMinimumValue() {

src/main/java/org/scijava/module/AbstractModuleItem.java

@@ -74,6 +74,8 @@ public String toString() {
 		sm.append("persistKey", getPersistKey());
 		sm.append("callback", getCallback());
 		sm.append("widgetStyle", getWidgetStyle());
+		sm.append("widgetGroup", getWidgetGroup());
+		sm.append("expanded", isExpanded());
 		sm.append("default", getDefaultValue());
 		sm.append("min", getMinimumValue());
 		sm.append("max", getMaximumValue());
@@ -231,6 +233,16 @@ public void callback(final Module module) throws MethodCallException {
 	public String getWidgetStyle() {
 		return null;
 	}
+
+	@Override
+	public String getWidgetGroup() {
+		return null;
+	}
+
+	@Override
+	public boolean isExpanded() {
+		return true;
+	}
 
 	@Override
 	public T getDefaultValue() {

src/main/java/org/scijava/module/DefaultMutableModuleItem.java

@@ -59,6 +59,8 @@ public class DefaultMutableModuleItem<T> extends AbstractModuleItem<T>
 	private String validater;
 	private String callback;
 	private String widgetStyle;
+	private String widgetGroup;
+	private boolean expanded;
 	private T defaultValue;
 	private T minimumValue;
 	private T maximumValue;
@@ -94,6 +96,8 @@ public DefaultMutableModuleItem(final ModuleInfo info, final String name,
 		validater = super.getValidater();
 		callback = super.getCallback();
 		widgetStyle = super.getWidgetStyle();
+		widgetGroup = super.getWidgetGroup();
+		expanded = super.isExpanded();
 		minimumValue = super.getMinimumValue();
 		maximumValue = super.getMaximumValue();
 		stepSize = super.getStepSize();
@@ -122,6 +126,8 @@ public DefaultMutableModuleItem(final ModuleInfo info,
 		validater = item.getValidater();
 		callback = item.getCallback();
 		widgetStyle = item.getWidgetStyle();
+		widgetGroup = item.getWidgetGroup();
+		expanded = item.isExpanded();
 		minimumValue = item.getMinimumValue();
 		maximumValue = item.getMaximumValue();
 		softMinimum = item.getSoftMinimum();
@@ -185,6 +191,16 @@ public void setCallback(final String callback) {
 	public void setWidgetStyle(final String widgetStyle) {
 		this.widgetStyle = widgetStyle;
 	}
+
+	@Override
+	public void setWidgetGroup(final String widgetGroup) {
+		this.widgetGroup = widgetGroup;
+	}
+
+	@Override
+	public void setExpanded(final boolean expanded) {
+		this.expanded = expanded;
+	}
 
 	@Override
 	public void setDefaultValue(final T defaultValue) {
@@ -288,6 +304,16 @@ public String getCallback() {
 	public String getWidgetStyle() {
 		return widgetStyle;
 	}
+
+	@Override
+	public String getWidgetGroup() {
+		return widgetGroup;
+	}
+
+	@Override
+	public boolean isExpanded() {
+		return expanded;
+	}
 
 	@Override
 	public T getDefaultValue() {

src/main/java/org/scijava/module/ModuleItem.java

@@ -153,6 +153,15 @@ public interface ModuleItem<T> extends BasicDetails {
 	 * interface.
 	 */
 	String getWidgetStyle();
+
+	/**
+	 * Gets the name of the group the widget belongs to so it can be displayed within
+	 * the group.
+	 */
+	String getWidgetGroup();
+
+	/** Returns the state of the widget group, expanded and visible or not expanded and hidden. */
+	boolean isExpanded();
 
 	/** Gets the default value. */
 	T getDefaultValue();

src/main/java/org/scijava/module/MutableModuleItem.java

@@ -61,6 +61,10 @@ public interface MutableModuleItem<T> extends ModuleItem<T> {
 	void setCallback(String callback);
 
 	void setWidgetStyle(String widgetStyle);
+
+	void setWidgetGroup(String widgetGroup);
+
+	void setExpanded(boolean expanded);
 
 	void setDefaultValue(T defaultValue);
 

src/main/java/org/scijava/plugin/Parameter.java

@@ -92,6 +92,9 @@
 	 * output, such as a "verbose" flag.</li>
 	 * <li>MESSAGE: parameter value is intended as a message only, not editable by
 	 * the user nor included as an input or output parameter.</li>
+	 * <li>GROUP: parameter value specifies a widget group, not editable by
+	 * the user nor included as an input or output parameter. Members are added
+	 * to the group using the group parameter annotation.</li>
 	 * </ul>
 	 */
 	ItemVisibility visibility() default ItemVisibility.NORMAL;
@@ -142,6 +145,15 @@
 	 * </p>
 	 */
 	String style() default "";
+
+	/** Defines the widget group. */
+	String group() default "";
+
+	/** 
+	 * Defines the state of the widget group. When true the group is expanded and visible. 
+	 * Otherwise, group members are hidden.
+	 * */
+	boolean expanded() default true;
 
 	/** Defines the minimum allowed value (numeric parameters only). */
 	String min() default "";

src/main/java/org/scijava/script/process/ParameterScriptProcessor.java

@@ -277,6 +277,8 @@ private <T> void assignAttribute(final DefaultMutableModuleItem<T> item,
 		else if (is(k, "softMin")) item.setSoftMinimum(as(v, item.getType()));
 		else if (is(k, "stepSize")) item.setStepSize(as(v, double.class));
 		else if (is(k, "style")) item.setWidgetStyle(as(v, String.class));
+		else if (is(k, "group")) item.setWidgetGroup(as(v, String.class));
+		else if (is(k, "expanded")) item.setExpanded(as(v, boolean.class));
 		else if (is(k, "visibility")) item.setVisibility(as(v, ItemVisibility.class));
 		else if (is(k, "value")) item.setDefaultValue(as(v, item.getType()));
 		else item.set(k, v.toString());

src/main/java/org/scijava/widget/DefaultWidgetModel.java

@@ -131,6 +131,11 @@ public String getWidgetLabel() {
 	public boolean isStyle(final String style) {
 		return WidgetStyle.isStyle(getItem(), style);
 	}
+
+	@Override
+	public String getGroup() {
+		return getItem().getWidgetGroup();
+	}
 
 	@Override
 	public Object getValue() {

src/main/java/org/scijava/widget/WidgetModel.java

@@ -80,6 +80,13 @@ public interface WidgetModel extends Contextual {
 	 * {@code style.equals(getItem().getWidgetStyle())}.
 	 */
 	boolean isStyle(String style);
+
+	/**
+	 * Gets group that the widget belongs to.
+	 * 
+	 * @return Group that the widget belongs to.
+	 */
+	String getGroup();
 
 	/**
 	 * Gets the current value of the module input.

src/test/java/org/scijava/script/ScriptInfoTest.java

@@ -266,18 +266,18 @@ public void testParameters() {
 
 		final ModuleItem<?> log = info.getInput("log");
 		assertItem("log", LogService.class, null, ItemIO.INPUT, false, true, null,
-			null, null, null, null, null, null, null, noChoices, log);
+			null, null, null, null, null, null, null, null, noChoices, log);
 
 		final ModuleItem<?> sliderValue = info.getInput("sliderValue");
 		assertItem("sliderValue", int.class, "Slider Value", ItemIO.INPUT, true,
-			true, null, " slidEr,", 11, null, null, 5, 15, 3.0, noChoices, sliderValue);
+			true, null, " slidEr,", null, 11, null, null, 5, 15, 3.0, noChoices, sliderValue);
 		assertTrue("Case-insensitive trimmed style", WidgetStyle.isStyle(sliderValue, "slider"));
 
 		final ModuleItem<?> animal = info.getInput("animal");
 		final List<String> animalChoices = //
 			Arrays.asList("quick brown fox", "lazy dog");
 		assertItem("animal", String.class, null, ItemIO.INPUT, true, false,
-			null, null, null, null, null, null, null, null, animalChoices, animal);
+			null, null, null, null, null, null, null, null, null, animalChoices, animal);
 		assertEquals(animal.get("family"), "Carnivora"); // test custom attribute
 
 		final ModuleItem<?> notAutoFilled = info.getInput("notAutoFilled");
@@ -288,7 +288,7 @@ public void testParameters() {
 
 		final ModuleItem<?> buffer = info.getOutput("buffer");
 		assertItem("buffer", StringBuilder.class, null, ItemIO.BOTH, true, true,
-			null, null, null, null, null, null, null, null, noChoices, buffer);
+			null, null, null, null, null, null, null, null, null, noChoices, buffer);
 
 		int inputCount = 0;
 		final ModuleItem<?>[] inputs = { log, sliderValue, animal, notAutoFilled, msg, buffer };
@@ -367,7 +367,7 @@ private String id(final String path, final String script) {
 	private void assertItem(final String name, final Class<?> type,
 		final String label, final ItemIO ioType, final boolean required,
 		final boolean persist, final String persistKey, final String style,
-		final Object value, final Object min, final Object max,
+		final String group, final Object value, final Object min, final Object max,
 		final Object softMin, final Object softMax, final Number stepSize,
 		final List<?> choices, final ModuleItem<?> item)
 	{
@@ -379,6 +379,7 @@ private void assertItem(final String name, final Class<?> type,
 		assertEquals(persist, item.isPersisted());
 		assertEquals(persistKey, item.getPersistKey());
 		assertEquals(style, item.getWidgetStyle());
+		assertEquals(group, item.getWidgetGroup());
 		assertEquals(value, item.getDefaultValue());
 		assertEquals(min, item.getMinimumValue());
 		assertEquals(max, item.getMaximumValue());