Added a Registry.find() (ReactiveX#478)

Add find() method that will only return an existing object in a Registry
but will not create a new one.

Author: KingMob

resilience4j-core/src/main/java/io/github/resilience4j/core/Registry.java

@@ -38,6 +38,13 @@ public interface Registry<E, C> {
 	 */
 	void addConfiguration(String configName, C configuration);
 
+	/**
+	 * Find a named entry in the Registry
+	 *
+	 * @param name    the  name
+	 */
+	Optional<E> find(String name);
+
 	/**
 	 * Remove an entry from the Registry
 	 *

resilience4j-core/src/main/java/io/github/resilience4j/core/registry/AbstractRegistry.java

@@ -58,6 +58,11 @@ protected E computeIfAbsent(String name, Supplier<E> supplier){
 		});
 	}
 
+	@Override
+	public Optional<E> find(String name){
+		return Optional.ofNullable(entryMap.get(name));
+	}
+
 	@Override
 	public Optional<E> remove(String name){
 		Optional<E> removedEntry = Optional.ofNullable(entryMap.remove(name));

resilience4j-core/src/test/java/io/github/resilience4j/core/registry/AbstractRegistryTest.java

@@ -76,6 +76,16 @@ public void shouldConsumeRegistryEvents() {
 
 	}
 
+	@Test
+	public void shouldOnlyFindRegisteredObjects() {
+		TestRegistry testRegistry = new TestRegistry();
+
+		assertThat(testRegistry.find("test")).isEmpty();
+		testRegistry.entryMap.put("test", "value");
+		assertThat(testRegistry.find("test")).contains("value");
+	}
+
+
 	class TestRegistry extends AbstractRegistry<String, String> {
 
 		public TestRegistry() {
@@ -85,4 +95,4 @@ public TestRegistry() {
 		}
 	}
 
-}
+}