ModuleService: add getDefaultValue

pom.xml

@@ -10,7 +10,7 @@
 	</parent>
 
 	<artifactId>scijava-common</artifactId>
-	<version>2.40.1-SNAPSHOT</version>
+	<version>2.41.0-SNAPSHOT</version>
 
 	<name>SciJava Common</name>
 	<description>SciJava Common is a shared library for SciJava software. It provides a plugin framework, with an extensible mechanism for service discovery, backed by its own annotation processor, so that plugins can be loaded dynamically. It is used by both ImageJ and SCIFIO.</description>

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

@@ -92,7 +92,7 @@ public class DefaultModuleService extends AbstractService implements
 	private PrefService prefService;
 
 	@Parameter
-	private ConvertService conversionService;
+	private ConvertService convertService;
 
 	/** Index of registered modules. */
 	private ModuleIndex moduleIndex;
@@ -269,7 +269,7 @@ public <T> void save(final ModuleItem<T> item, final T value) {
 		final String sValue = value == null ? "" : value.toString();
 
 		// do not persist if object cannot be converted back from a string
-		if (!conversionService.supports(sValue, item.getType())) return;
+		if (!convertService.supports(sValue, item.getType())) return;
 
 		final String persistKey = item.getPersistKey();
 		if (persistKey == null || persistKey.isEmpty()) {
@@ -297,9 +297,25 @@ public <T> T load(final ModuleItem<T> item) {
 		// if persisted value has never been set before return null
 		if (sValue == null) return null;
 
-		return conversionService.convert(sValue, item.getType());
+		return convertService.convert(sValue, item.getType());
 	}
 
+	@Override
+	public <T> T getDefaultValue(final ModuleItem<T> item) {
+		final T min = item.getMinimumValue();
+		if (min != null) return min;
+		final T softMin = item.getSoftMinimum();
+		if (softMin != null) return softMin;
+		final T max = item.getMaximumValue();
+		if (max != null) return max;
+		final T softMax = item.getSoftMaximum();
+		if (softMax != null) return softMax;
+		final T zero = convertService.convert("0", item.getType());
+		if (zero != null) return zero;
+		// no known default value
+		return null;
+	}
+
 	// -- Service methods --
 
 	@Override
@@ -399,7 +415,7 @@ private void assignInputs(final Module module,
 			}
 			else {
 				final Class<?> type = input.getType();
-				converted = conversionService.convert(value, type);
+				converted = convertService.convert(value, type);
 				if (value != null && converted == null) {
 					log.error("For input " + name + ": incompatible object " +
 						value.getClass().getName() + " for type " + type.getName());

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

@@ -285,4 +285,8 @@ <M extends Module> Future<M> run(M module,
 	 * {@link ModuleItem}.
 	 */
 	<T> T load(ModuleItem<T> item);
+
+	/** Gets the default value of the given {@link ModuleItem}. */
+	<T> T getDefaultValue(final ModuleItem<T> item);
+
 }