HandlerService: push default method impls to iface

Some minor tweaking is needed in the TextService, since it overrides
interface methods in order to specify different javadoc content.

Author: ctrueden

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

@@ -41,22 +41,5 @@
 public abstract class AbstractHandlerService<DT, PT extends HandlerPlugin<DT>>
 	extends AbstractSingletonService<PT> implements HandlerService<DT, PT>
 {
-
-	// -- HandlerService methods --
-
-	@Override
-	public PT getHandler(final DT data) {
-		for (final PT handler : getInstances()) {
-			if (handler.supports(data)) return handler;
-		}
-		return null;
-	}
-
-	// -- Typed methods --
-
-	@Override
-	public boolean supports(final DT data) {
-		return getHandler(data) != null;
-	}
-
+	// NB: No implementation needed.
 }

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

@@ -54,9 +54,12 @@ public interface HandlerService<DT, PT extends HandlerPlugin<DT>> extends
 	 * Gets the most appropriate handler for the given data object, or null if no
 	 * handler supports it.
 	 */
-	PT getHandler(DT data);
-
-	// NB: Javadoc overrides.
+	default PT getHandler(final DT data) {
+		for (final PT handler : getInstances()) {
+			if (handler.supports(data)) return handler;
+		}
+		return null;
+	}
 
 	// -- SingletonService methods --
 
@@ -71,6 +74,7 @@ public interface HandlerService<DT, PT extends HandlerPlugin<DT>> extends
 
 	/** Gets whether the given data object is supported. */
 	@Override
-	boolean supports(DT data);
-
+	default boolean supports(final DT data) {
+		return getHandler(data) != null;
+	}
 }

src/main/java/org/scijava/text/TextService.java

@@ -59,7 +59,9 @@ public interface TextService extends HandlerService<File, TextFormat>,
 
 	/** Gets the text format which best handles the given file. */
 	@Override
-	TextFormat getHandler(File file);
+	default TextFormat getHandler(File file) {
+		return HandlerService.super.getHandler(file);
+	}
 
 	// -- SingletonService methods --
 
@@ -71,6 +73,7 @@ public interface TextService extends HandlerService<File, TextFormat>,
 
 	/** Gets whether the given file contains text data in a supported format. */
 	@Override
-	boolean supports(File file);
-
+	default boolean supports(final File file) {
+		return HandlerService.super.supports(file);
+	}
 }