Revamp Discoverer interface

gselzer · ctrueden · commit ae6697ab385d · 2022-04-13T12:10:57.000-05:00
This commit provides major changes to the Discoverer interface.
1. We rename implementingClasses to implsOfType
2. We add the elementsTaggedWith(String key) method
3. We make both elements default, so that Discoverers can decide to
implement only one of the two methods.
diff --git a/scijava/scijava-discovery/src/main/java/org/scijava/discovery/Discoverer.java b/scijava/scijava-discovery/src/main/java/org/scijava/discovery/Discoverer.java
@@ -1,10 +1,20 @@
 
 package org.scijava.discovery;
 
+import java.lang.reflect.AnnotatedElement;
+import java.util.Collections;
 import java.util.List;
 
 public interface Discoverer {
 
-	<T> List<Class<T>> implementingClasses(Class<T> c);
+	@SuppressWarnings("unused")
+	default <T> List<Class<T>> implsOfType(Class<T> c) {
+		return Collections.emptyList();
+	}
+
+	@SuppressWarnings("unused")
+	default List<AnnotatedElement> elementsTaggedWith(String... tags) {
+		return Collections.emptyList();
+	}
 
 }
diff --git a/scijava/scijava-discovery/src/main/java/org/scijava/discovery/StaticDiscoverer.java b/scijava/scijava-discovery/src/main/java/org/scijava/discovery/StaticDiscoverer.java
@@ -20,7 +20,7 @@ public void register(Class<?> c, String name) {
 
 	@SuppressWarnings("unchecked")
 	@Override
-	public <T> List<Class<T>> implementingClasses(Class<T> c) {
+	public <T> List<Class<T>> implsOfType(Class<T> c) {
 		return names.keySet().stream() //
 			.filter(cls -> cls.isAssignableFrom(c)) //
 			.map(cls -> (Class<T>) cls) //
diff --git a/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/DefaultOpEnvironment.java b/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/DefaultOpEnvironment.java
@@ -183,7 +183,7 @@ public static List<MatchingRoutine> getMatchingRoutines(
 	{
 		List<MatchingRoutine> matchers = new ArrayList<>();
 		for (Discoverer d : discoverers) {
-			List<Class<MatchingRoutine>> implementingClasses = d.implementingClasses(
+			List<Class<MatchingRoutine>> implementingClasses = d.implsOfType(
 				MatchingRoutine.class);
 			List<MatchingRoutine> routines = implementingClasses.parallelStream().map(
 				c -> {
@@ -564,7 +564,7 @@ private synchronized void initWrappers() {
 		if (wrappers != null) return;
 		wrappers = new HashMap<>();
 		for (Discoverer d : discoverers)
-			for (Class<OpWrapper> cls : d.implementingClasses(OpWrapper.class)) {
+			for (Class<OpWrapper> cls : d.implsOfType(OpWrapper.class)) {
 				OpWrapper<?> wrapper;
 				try {
 					wrapper = cls.getDeclaredConstructor().newInstance();
@@ -580,7 +580,7 @@ private synchronized void initInfoChainGenerators() {
 		if (infoChainGenerators != null) return;
 		Set<InfoChainGenerator> generators = new HashSet<>();
 		for (Discoverer d : discoverers)
-			for (Class<InfoChainGenerator> cls : d.implementingClasses(
+			for (Class<InfoChainGenerator> cls : d.implsOfType(
 				InfoChainGenerator.class))
 			{
 				InfoChainGenerator wrapper;
diff --git a/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/DefaultOpService.java b/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/DefaultOpService.java
@@ -125,7 +125,7 @@ public PluginBasedDiscoverer(Context ctx) {
 
 	@Override
 	@SuppressWarnings("unchecked")
-	public <T> List<Class<T>> implementingClasses(Class<T> c) {
+	public <T> List<Class<T>> implsOfType(Class<T> c) {
 		if (!SciJavaPlugin.class.isAssignableFrom(c)) {
 			throw new UnsupportedOperationException(
 				"Current discovery mechanism tied to SciJava Context; only able to search for SciJavaPlugins");
diff --git a/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/OpClassBasedClassOpInfoGenerator.java b/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/OpClassBasedClassOpInfoGenerator.java
@@ -25,7 +25,7 @@ public OpClassBasedClassOpInfoGenerator(Discoverer... d) {
 	@Override
 	public List<OpInfo> generateInfos() {
 		List<OpInfo> infos = discoverers.stream() //
-			.flatMap(d -> d.implementingClasses(Op.class).stream()) //
+			.flatMap(d -> d.implsOfType(Op.class).stream()) //
 			.filter(cls -> cls.getAnnotation(OpClass.class) != null) //
 			.map(cls -> {
 				OpClass p = cls.getAnnotation(OpClass.class);
diff --git a/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/OpCollectionInfoGenerator.java b/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/OpCollectionInfoGenerator.java
@@ -32,7 +32,7 @@ public OpCollectionInfoGenerator(Discoverer... d) {
 	@Override
 	public List<OpInfo> generateInfos() {
 		List<OpInfo> infos = discoverers.stream() //
-			.flatMap(d -> d.implementingClasses(OpCollection.class).stream()) //
+			.flatMap(d -> d.implsOfType(OpCollection.class).stream()) //
 			.map(cls -> {
 			try {
 				String version = VersionUtils.getVersion(cls);
diff --git a/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/PluginBasedClassOpInfoGenerator.java b/scijava/scijava-ops-engine/src/main/java/org/scijava/ops/engine/impl/PluginBasedClassOpInfoGenerator.java
@@ -25,7 +25,7 @@ public PluginBasedClassOpInfoGenerator(Discoverer... d) {
 	@Override
 	public List<OpInfo> generateInfos() {
 		List<OpInfo> infos = discoverers.stream() //
-			.flatMap(d -> d.implementingClasses(Op.class).stream()) //
+			.flatMap(d -> d.implsOfType(Op.class).stream()) //
 			.filter(cls -> cls.getAnnotation(Plugin.class) != null) //
 			.map(cls -> {
 				Plugin p = cls.getAnnotation(Plugin.class);
diff --git a/scijava/scijava-ops-serviceloader/src/main/java/org/scijava/ops/serviceloader/ServiceLoaderDiscoverer.java b/scijava/scijava-ops-serviceloader/src/main/java/org/scijava/ops/serviceloader/ServiceLoaderDiscoverer.java
@@ -12,7 +12,7 @@ public class ServiceLoaderDiscoverer implements Discoverer {
 
 	@SuppressWarnings("unchecked")
 	@Override
-	public <T> List<Class<T>> implementingClasses(Class<T> c) {
+	public <T> List<Class<T>> implsOfType(Class<T> c) {
 		// If we cannot use c, we cannot find any implementations
 		Module thisModule = this.getClass().getModule();
 		if (!thisModule.canUse(c)) return Collections.emptyList();
diff --git a/scijava/scijava-ops-serviceloader/src/test/java/org/scijava/ops/serviceloader/ServiceLoaderDiscovererTest.java b/scijava/scijava-ops-serviceloader/src/test/java/org/scijava/ops/serviceloader/ServiceLoaderDiscovererTest.java
@@ -13,15 +13,15 @@ public class ServiceLoaderDiscovererTest {
 	@Test
 	public void testServiceLoaderWithOps() {
 		Discoverer d = new ServiceLoaderDiscoverer();
-		List<Class<Op>> implementingClasses = d.implementingClasses(Op.class);
+		List<Class<Op>> implementingClasses = d.implsOfType(Op.class);
 		Assert.assertTrue(implementingClasses.contains(ServiceBasedAdder.class));
 		Assert.assertEquals(implementingClasses.size(), 1);
 	}
 
 	@Test
 	public void testServiceLoaderWithOpCollections() {
 		Discoverer d = new ServiceLoaderDiscoverer();
-		List<Class<OpCollection>> implementingClasses = d.implementingClasses(OpCollection.class);
+		List<Class<OpCollection>> implementingClasses = d.implsOfType(OpCollection.class);
 		Assert.assertTrue(implementingClasses.contains(ServiceBasedMultipliers.class));
 		Assert.assertEquals(implementingClasses.size(), 1);
 	}
