LazyObjects: add getType() method

This breaks backwards compatibility, so bumps the development snapshot
version to 3.0.0.

The rationale is to make it possible for the ObjectIndex to better
discriminate which objects should be resolved for a particular call to
ObjectIndex#get(Class). The current behavior is to resolve _all_ pending
objects with _any_ call to get(Class), which is generally suboptimal.

Author: ctrueden

pom.xml

@@ -10,7 +10,7 @@
 	</parent>
 
 	<artifactId>scijava-common</artifactId>
-	<version>2.25.1-SNAPSHOT</version>
+	<version>3.0.0-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/object/LazyObjects.java

@@ -45,4 +45,11 @@ public interface LazyObjects<T> {
 	/** Gets the collection of objects. */
 	Collection<T> get();
 
+	/**
+	 * The type of the objects which will be resolved from a call to
+	 * {@link #get()}. This information is used to determine whether to resolve
+	 * the objects in response to an {@link ObjectIndex#get(Class)} call.
+	 */
+	Class<?> getType();
+
 }

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

@@ -86,6 +86,12 @@ public void initialize() {
 			public ArrayList<PT> get() {
 				return new ArrayList<PT>(getInstances());
 			}
+
+			@Override
+			public Class<?> getType() {
+				return getPluginType();
+			}
+
 		});
 	}
 

src/main/java/org/scijava/script/DefaultScriptService.java

@@ -283,6 +283,11 @@ public Collection<ScriptInfo> get() {
 				return scripts().values();
 			}
 
+			@Override
+			public Class<?> getType() {
+				return ScriptInfo.class;
+			}
+
 		});
 	}
 

src/test/java/org/scijava/object/ObjectIndexTest.java

@@ -71,6 +71,11 @@ public Collection<String> get() {
 				return Arrays.asList(o4, o5, o6);
 			}
 
+			@Override
+			public Class<?> getType() {
+				return String.class;
+			}
+
 		});
 
 		final List<Object> all = objectIndex.getAll();