diff --git a/src/main/java/org/scijava/module/DefaultModuleService.java b/src/main/java/org/scijava/module/DefaultModuleService.java
@@ -260,27 +260,23 @@ public <M extends Module> M waitFor(final Future<M> future) {
	}

	@Override
-	public <T> ModuleItem<T> getSingleInput(final Module module,
-		final Class<T> type)
-	{
-		return getTypedSingleItem(module, type, module.getInfo().inputs());
	}

	@Override
-	public <T> ModuleItem<T> getSingleOutput(final Module module,
-		final Class<T> type)
-	{
-		return getTypedSingleItem(module, type, module.getInfo().outputs());
	}

	@Override
-	public ModuleItem<?> getSingleInput(Module module, Collection<Class<?>> types) {
-		return getSingleItem(module, types, module.getInfo().inputs());
	}

	@Override
-	public ModuleItem<?> getSingleOutput(Module module, Collection<Class<?>> types) {
-		return getSingleItem(module, types, module.getInfo().outputs());
	}

	@Override
@@ -478,24 +474,25 @@ private void assignInputs(final Module module,
	}

	private <T> ModuleItem<T> getTypedSingleItem(final Module module,
-		final Class<T> type, final Iterable<ModuleItem<?>> items)
	{
		Set<Class<?>> types = new HashSet<>();
		types.add(type);
		@SuppressWarnings("unchecked")
-		ModuleItem<T> result = (ModuleItem<T>) getSingleItem(module, types, items);
		return result;
	}

	private ModuleItem<?> getSingleItem(final Module module,
-		final Collection<Class<?>> types, final Iterable<ModuleItem<?>> items)
	{
		ModuleItem<?> result = null;

		for (final ModuleItem<?> item : items) {
			final String name = item.getName();
			if (!item.isAutoFill()) continue; // skip unfillable inputs
			if (module.isInputResolved(name)) continue; // skip resolved inputs
			final Class<?> itemType = item.getType();
			for (final Class<?> type : types) {
				if (type.isAssignableFrom(itemType)) {

diff --git a/src/main/java/org/scijava/module/ModuleService.java b/src/main/java/org/scijava/module/ModuleService.java
@@ -272,26 +272,66 @@ <M extends Module> Future<M> run(M module,
	 * given type, returning the relevant {@link ModuleItem} if found, or null if
	 * not exactly one unresolved fillable input of that type.
	 */
-	<T> ModuleItem<T> getSingleInput(Module module, Class<T> type);

	/**
	 * Checks the given module for a solitary unresolved output of the given type,
	 * returning the relevant {@link ModuleItem} if found, or null if not exactly
	 * one unresolved output of that type.
	 */
-	<T> ModuleItem<T> getSingleOutput(Module module, Class<T> type);

	/**
	 * As {@link #getSingleInput(Module, Class)} but will match with a set of
	 * potential classes, at the cost of generic parameter safety.
	 */
-	ModuleItem<?> getSingleInput(Module module, Collection<Class<?>> types);

	/**
	 * As {@link #getSingleOutput(Module, Class)} but will match with a set of
	 * potential classes, at the cost of generic parameter safety.
	 */
-	ModuleItem<?> getSingleOutput(Module module, Collection<Class<?>> types);

	/**
	 * Registers the given value for the given {@link ModuleItem} using the

diff --git a/src/main/java/org/scijava/ui/FileListPreprocessor.java b/src/main/java/org/scijava/ui/FileListPreprocessor.java
@@ -32,6 +32,7 @@

import org.scijava.module.Module;
import org.scijava.module.ModuleItem;
import org.scijava.module.process.AbstractPreprocessorPlugin;
import org.scijava.module.process.PreprocessorPlugin;
import org.scijava.plugin.Parameter;
@@ -44,10 +45,13 @@ public class FileListPreprocessor extends AbstractPreprocessorPlugin {
	@Parameter(required = false)
	private UIService uiService;

	@Override
	public void process(final Module module) {
-		if (uiService == null) return;
-		final ModuleItem<File[]> fileInput = getFilesInput(module);
		if (fileInput == null) return;

		final File[] files = fileInput.getValue(module);
@@ -65,30 +69,4 @@ public void process(final Module module) {
		module.resolveInput(fileInput.getName());
	}

-	// -- Helper methods --
-
-	/**
-	 * Gets the single unresolved {@link File} input parameter. If there is not
-	 * exactly one unresolved {@link File} input parameter, or if there are other
-	 * types of unresolved parameters, this method returns null.
-	 */
-	private ModuleItem<File[]> getFilesInput(final Module module) {
-		ModuleItem<File[]> result = null;
-		for (final ModuleItem<?> input : module.getInfo().inputs()) {
-			if (module.isInputResolved(input.getName())) continue;
-			final Class<?> type = input.getType();
-			if (!File[].class.isAssignableFrom(type)) {
-				// not a File[] parameter; abort
-				return null;
-			}
-			if (result != null) {
-				// second File parameter; abort
-				return null;
-			}
-			@SuppressWarnings("unchecked")
-			final ModuleItem<File[]> fileInput = (ModuleItem<File[]>) input;
-			result = fileInput;
-		}
-		return result;
-	}
}
diff --git a/src/test/java/org/scijava/ui/FileListPreprocessorTest.java b/src/test/java/org/scijava/ui/FileListPreprocessorTest.java
@@ -0,0 +1,109 @@