Return a list of all extensions from a plugin and optional for an extension point

demo/app/src/main/java/ro/fortsoft/pf4j/demo/Boot.java

@@ -56,13 +56,13 @@ public class Boot {
         }
 
         // print extensions from classpath (non plugin)
-        System.out.println(String.format("Extensions added by classpath:"));
+        System.out.println("Extensions added by classpath:");
         Set<String> extensionClassNames = pluginManager.getExtensionClassNames(null);
         for (String extension : extensionClassNames) {
             System.out.println("   " + extension);
         }
 
-        // print extensions for each started plugin
+        // print extensions ids for each started plugin
         List<PluginWrapper> startedPlugins = pluginManager.getStartedPlugins();
         for (PluginWrapper plugin : startedPlugins) {
             String pluginId = plugin.getDescriptor().getPluginId();
@@ -73,6 +73,33 @@ public class Boot {
             }
         }
 
+        // print the extensions instances for Greeting extension point for each started plugin
+        for (PluginWrapper plugin : startedPlugins) {
+            String pluginId = plugin.getDescriptor().getPluginId();
+            System.out.println(String.format("Extensions instances added by plugin '%s' for extension point '%s':", pluginId, Greeting.class.getName()));
+            List<Greeting> extensions = pluginManager.getExtensions(Greeting.class, pluginId);
+            for (Object extension : extensions) {
+                System.out.println("   " + extension);
+            }
+        }
+
+        // print extensions instances from classpath (non plugin)
+        System.out.println("Extensions instances added by classpath:");
+        List extensions = pluginManager.getExtensions((String) null);
+        for (Object extension : extensions) {
+            System.out.println("   " + extension);
+        }
+
+        // print extensions instances for each started plugin
+        for (PluginWrapper plugin : startedPlugins) {
+            String pluginId = plugin.getDescriptor().getPluginId();
+            System.out.println(String.format("Extensions instances added by plugin '%s':", pluginId));
+            extensions = pluginManager.getExtensions(pluginId);
+            for (Object extension : extensions) {
+                System.out.println("   " + extension);
+            }
+        }
+
         // stop the plugins
         pluginManager.stopPlugins();
         /*

pf4j/src/main/java/ro/fortsoft/pf4j/AbstractExtensionFinder.java

@@ -48,67 +48,131 @@ public abstract class AbstractExtensionFinder implements ExtensionFinder, Plugin
 	public <T> List<ExtensionWrapper<T>> find(Class<T> type) {
 		log.debug("Finding extensions of extension point '{}'", type.getName());
         Map<String, Set<String>> entries = getEntries();
+        List<ExtensionWrapper<T>> result = new ArrayList<>();
+
+        // add extensions found in classpath
+        List<ExtensionWrapper<T>> classpathExtensions = find(type, null);
+        result.addAll(classpathExtensions);
+
+        // add extensions found in each plugin
+        for (String pluginId : entries.keySet()) {
+            List<ExtensionWrapper<T>> pluginExtensions = find(type, pluginId);
+            result.addAll(pluginExtensions);
+        }
+
+        if (entries.isEmpty()) {
+        	log.debug("No extensions found for extension point '{}'", type.getName());
+        } else {
+        	log.debug("Found {} extensions for extension point '{}'", result.size(), type.getName());
+        }
+
+        // sort by "ordinal" property
+        Collections.sort(result);
+
+		return result;
+	}
 
+    @Override
+    @SuppressWarnings("unchecked")
+    public <T> List<ExtensionWrapper<T>> find(Class<T> type, String pluginId) {
+        log.debug("Finding extensions of extension point '{}' for plugin '{}'", type.getName(), pluginId);
         List<ExtensionWrapper<T>> result = new ArrayList<>();
-        for (Map.Entry<String, Set<String>> entry : entries.entrySet()) {
-            if (entry.getValue().isEmpty()) {
-                continue;
+
+        Set<String> classNames = findClassNames(pluginId);
+        if (classNames.isEmpty()) {
+            return result;
+        }
+
+        if (pluginId != null) {
+            PluginWrapper pluginWrapper = pluginManager.getPlugin(pluginId);
+            if (PluginState.STARTED != pluginWrapper.getPluginState()) {
+                return result;
             }
 
-            String pluginId = entry.getKey();
+            log.trace("Checking extensions from plugin '{}'", pluginId);
+        } else {
+            log.trace("Checking extensions from classpath");
+        }
+
+        ClassLoader classLoader = (pluginId != null) ? pluginManager.getPluginClassLoader(pluginId) : getClass().getClassLoader();
 
-            if (pluginId != null) {
-                PluginWrapper pluginWrapper = pluginManager.getPlugin(pluginId);
-                if (PluginState.STARTED != pluginWrapper.getPluginState()) {
-                    continue;
+        for (String className : classNames) {
+            try {
+                log.debug("Loading class '{}' using class loader '{}'", className, classLoader);
+                Class<?> extensionClass = classLoader.loadClass(className);
+
+                log.debug("Checking extension type '{}'", className);
+                if (type.isAssignableFrom(extensionClass)) {
+                    ExtensionWrapper extensionWrapper = createExtensionWrapper(extensionClass);
+                    result.add(extensionWrapper);
+                    log.debug("Added extension '{}' with ordinal {}", className, extensionWrapper.getOrdinal());
+                } else {
+                    log.trace("'{}' is not an extension for extension point '{}'", className, type.getName());
                 }
+            } catch (ClassNotFoundException e) {
+                log.error(e.getMessage(), e);
+            }
+        }
+
+        if (result.isEmpty()) {
+            log.debug("No extensions found for extension point '{}'", type.getName());
+        } else {
+            log.debug("Found {} extensions for extension point '{}'", result.size(), type.getName());
+        }
 
-                log.trace("Checking extensions from plugin '{}'", pluginId);
-            } else {
-                log.trace("Checking extensions from classpath");
+        // sort by "ordinal" property
+        Collections.sort(result);
+
+        return result;
+    }
+
+    @Override
+	public List<ExtensionWrapper> find(String pluginId) {
+        log.debug("Finding extensions from plugin '{}'", pluginId);
+        List<ExtensionWrapper> result = new ArrayList<>();
+
+	    Set<String> classNames = findClassNames(pluginId);
+        if (classNames.isEmpty()) {
+            return result;
+        }
+
+        if (pluginId != null) {
+            PluginWrapper pluginWrapper = pluginManager.getPlugin(pluginId);
+            if (PluginState.STARTED != pluginWrapper.getPluginState()) {
+                return result;
             }
 
-            ClassLoader classLoader = (pluginId != null) ? pluginManager.getPluginClassLoader(pluginId) : getClass().getClassLoader();
-
-            for (String className : entry.getValue()) {
-                try {
-                    log.debug("Loading class '{}' using class loader '{}'", className, classLoader);
-                    Class<?> extensionClass = classLoader.loadClass(className);
-
-                    log.debug("Checking extension type '{}'", className);
-                    if (type.isAssignableFrom(extensionClass)) {
-                        ExtensionDescriptor descriptor = new ExtensionDescriptor();
-                        int ordinal = 0;
-                        if (extensionClass.isAnnotationPresent(Extension.class)) {
-                            ordinal = extensionClass.getAnnotation(Extension.class).ordinal();
-                        }
-                        descriptor.setOrdinal(ordinal);
-                        descriptor.setExtensionClass(extensionClass);
-
-                        ExtensionWrapper extensionWrapper = new ExtensionWrapper<>(descriptor);
-                        extensionWrapper.setExtensionFactory(pluginManager.getExtensionFactory());
-                        result.add(extensionWrapper);
-                        log.debug("Added extension '{}' with ordinal {}", className, ordinal);
-                    } else {
-                        log.trace("'{}' is not an extension for extension point '{}'", className, type.getName());
-                    }
-                } catch (ClassNotFoundException e) {
-                    log.error(e.getMessage(), e);
-                }
+            log.trace("Checking extensions from plugin '{}'", pluginId);
+        } else {
+            log.trace("Checking extensions from classpath");
+        }
+
+        ClassLoader classLoader = (pluginId != null) ? pluginManager.getPluginClassLoader(pluginId) : getClass().getClassLoader();
+
+        for (String className : classNames) {
+            try {
+                log.debug("Loading class '{}' using class loader '{}'", className, classLoader);
+                Class<?> extensionClass = classLoader.loadClass(className);
+
+                ExtensionWrapper extensionWrapper = createExtensionWrapper(extensionClass);
+                result.add(extensionWrapper);
+                log.debug("Added extension '{}' with ordinal {}", className, extensionWrapper.getOrdinal());
+            } catch (ClassNotFoundException e) {
+                log.error(e.getMessage(), e);
             }
         }
 
-        if (entries.isEmpty()) {
-        	log.debug("No extensions found for extension point '{}'", type.getName());
+        if (result.isEmpty()) {
+            log.debug("No extensions found for plugin '{}'", pluginId);
         } else {
-        	log.debug("Found {} extensions for extension point '{}'", result.size(), type.getName());
+            log.debug("Found {} extensions for plugin '{}'", result.size(), pluginId);
         }
 
         // sort by "ordinal" property
         Collections.sort(result);
 
-		return result;
-	}
+        return result;
+    }
 
     @Override
     public Set<String> findClassNames(String pluginId) {
@@ -122,6 +186,17 @@ public abstract class AbstractExtensionFinder implements ExtensionFinder, Plugin
         entries = null;
     }
 
+    protected void logExtensions(Set<String> extensions) {
+        if (extensions.isEmpty()) {
+            log.debug("No extensions found");
+        } else {
+            log.debug("Found possible {} extensions:", extensions.size());
+            for (String extension : extensions) {
+                log.debug("   " + extension);
+            }
+        }
+    }
+
     private Map<String, Set<String>> readStorages() {
         Map<String, Set<String>> result = new LinkedHashMap<>();
 
@@ -139,4 +214,19 @@ public abstract class AbstractExtensionFinder implements ExtensionFinder, Plugin
         return entries;
     }
 
+    private ExtensionWrapper createExtensionWrapper(Class<?> extensionClass) {
+        ExtensionDescriptor descriptor = new ExtensionDescriptor();
+        int ordinal = 0;
+        if (extensionClass.isAnnotationPresent(Extension.class)) {
+            ordinal = extensionClass.getAnnotation(Extension.class).ordinal();
+        }
+        descriptor.setOrdinal(ordinal);
+        descriptor.setExtensionClass(extensionClass);
+
+        ExtensionWrapper extensionWrapper = new ExtensionWrapper<>(descriptor);
+        extensionWrapper.setExtensionFactory(pluginManager.getExtensionFactory());
+
+        return extensionWrapper;
+    }
+
 }

pf4j/src/main/java/ro/fortsoft/pf4j/DefaultExtensionFinder.java

@@ -50,6 +50,27 @@ public class DefaultExtensionFinder implements ExtensionFinder, PluginStateListe
         return extensions;
     }
 
+    @Override
+    public <T> List<ExtensionWrapper<T>> find(Class<T> type, String pluginId) {
+        List<ExtensionWrapper<T>> extensions = new ArrayList<>();
+        for (ExtensionFinder finder : finders) {
+            extensions.addAll(finder.find(type, pluginId));
+        }
+
+        return extensions;
+    }
+
+    @Override
+    public List<ExtensionWrapper> find(String pluginId) {
+        List<ExtensionWrapper> extensions = new ArrayList<>();
+        for (ExtensionFinder finder : finders) {
+            extensions.addAll(finder.find(pluginId));
+        }
+
+        return extensions;
+    }
+
+
     @Override
     public Set<String> findClassNames(String pluginId) {
         Set<String> classNames = new HashSet<>();

pf4j/src/main/java/ro/fortsoft/pf4j/DefaultPluginManager.java

@@ -561,6 +561,29 @@ public class DefaultPluginManager implements PluginManager {
 		return extensions;
 	}
 
+    @Override
+    public <T> List<T> getExtensions(Class<T> type, String pluginId) {
+        List<ExtensionWrapper<T>> extensionsWrapper = extensionFinder.find(type, pluginId);
+        List<T> extensions = new ArrayList<>(extensionsWrapper.size());
+        for (ExtensionWrapper<T> extensionWrapper : extensionsWrapper) {
+            extensions.add(extensionWrapper.getExtension());
+        }
+
+        return extensions;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public List getExtensions(String pluginId) {
+        List<ExtensionWrapper> extensionsWrapper = extensionFinder.find(pluginId);
+        List extensions = new ArrayList<>(extensionsWrapper.size());
+        for (ExtensionWrapper extensionWrapper : extensionsWrapper) {
+            extensions.add(extensionWrapper.getExtension());
+        }
+
+        return extensions;
+    }
+
     @Override
     public Set<String> getExtensionClassNames(String pluginId) {
         return extensionFinder.findClassNames(pluginId);

pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionFinder.java

@@ -28,6 +28,16 @@ public interface ExtensionFinder {
      */
     <T> List<ExtensionWrapper<T>> find(Class<T> type);
 
+    /**
+     * Retrieves a list with all extensions found for an extension point and a plugin.
+     */
+    <T> List<ExtensionWrapper<T>> find(Class<T> type, String pluginId);
+
+    /**
+     * Retrieves a list with all extensions found for a plugin
+     */
+    List<ExtensionWrapper> find(String pluginId);
+
     /**
      * Retrieves a list with all extension class names found for a plugin.
      */

pf4j/src/main/java/ro/fortsoft/pf4j/ExtensionWrapper.java

@@ -30,7 +30,8 @@ public class ExtensionWrapper<T> implements Comparable<ExtensionWrapper<T>> {
         this.descriptor = descriptor;
 	}
 
-	public T getExtension() {
+	@SuppressWarnings("unchecked")
+    public T getExtension() {
         if (extension == null) {
             extension = (T) extensionFactory.create(descriptor.getExtensionClass());
         }

pf4j/src/main/java/ro/fortsoft/pf4j/LegacyExtensionFinder.java

@@ -59,14 +59,7 @@ public class LegacyExtensionFinder extends AbstractExtensionFinder {
                 LegacyExtensionStorage.read(reader, bucket);
             }
 
-            if (bucket.isEmpty()) {
-                log.debug("No extensions found");
-            } else {
-                log.debug("Found possible {} extensions:", bucket.size());
-                for (String entry : bucket) {
-                    log.debug("   " + entry);
-                }
-            }
+            logExtensions(bucket);
 
             result.put(null, bucket);
         } catch (IOException e) {
@@ -97,14 +90,7 @@ public class LegacyExtensionFinder extends AbstractExtensionFinder {
                     log.debug("Cannot find '{}'", getExtensionsResource());
                 }
 
-                if (bucket.isEmpty()) {
-                    log.debug("No extensions found");
-                } else {
-                    log.debug("Found possible {} extensions:", bucket.size());
-                    for (String entry : bucket) {
-                        log.debug("   " + entry);
-                    }
-                }
+                logExtensions(bucket);
 
                 result.put(pluginId, bucket);
             } catch (IOException e) {

pf4j/src/main/java/ro/fortsoft/pf4j/PluginManager.java

@@ -134,6 +134,10 @@ public interface PluginManager {
 
 	<T> List<T> getExtensions(Class<T> type);
 
+    <T> List<T> getExtensions(Class<T> type, String pluginId);
+
+    List getExtensions(String pluginId);
+
     Set<String> getExtensionClassNames(String pluginId);
 
     ExtensionFactory getExtensionFactory();

pf4j/src/main/java/ro/fortsoft/pf4j/ServiceProviderExtensionFinder.java

@@ -70,27 +70,11 @@ public class ServiceProviderExtensionFinder extends AbstractExtensionFinder {
                 } else {
                     extensionPath = Paths.get(url.toURI());
                 }
-                Files.walkFileTree(extensionPath, Collections.<FileVisitOption>emptySet(), 1, new SimpleFileVisitor<Path>() {
-
-                    @Override
-                    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
-                        log.debug("Read '{}'", file);
-                        Reader reader = Files.newBufferedReader(file, StandardCharsets.UTF_8);
-                        ServiceProviderExtensionStorage.read(reader, bucket);
-                        return FileVisitResult.CONTINUE;
-                    }
 
-                });
+                bucket.addAll(readExtensions(extensionPath));
             }
 
-            if (bucket.isEmpty()) {
-                log.debug("No extensions found");
-            } else {
-                log.debug("Found possible {} extensions:", bucket.size());
-                for (String entry : bucket) {
-                    log.debug("   " + entry);
-                }
-            }
+            logExtensions(bucket);
 
             result.put(null, bucket);
         } catch (IOException | URISyntaxException e) {
@@ -121,29 +105,13 @@ public class ServiceProviderExtensionFinder extends AbstractExtensionFinder {
                     } else {
                         extensionPath = Paths.get(url.toURI());
                     }
-                    Files.walkFileTree(extensionPath, Collections.<FileVisitOption>emptySet(), 1, new SimpleFileVisitor<Path>() {
-
-                        @Override
-                        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
-                            log.debug("Read '{}'", file);
-                            Reader reader = Files.newBufferedReader(file, StandardCharsets.UTF_8);
-                            ServiceProviderExtensionStorage.read(reader, bucket);
-                            return FileVisitResult.CONTINUE;
-                        }
 
-                    });
+                    bucket.addAll(readExtensions(extensionPath));
                 } else {
                     log.debug("Cannot find '{}'", getExtensionsResource());
                 }
 
-                if (bucket.isEmpty()) {
-                    log.debug("No extensions found");
-                } else {
-                    log.debug("Found possible {} extensions:", bucket.size());
-                    for (String entry : bucket) {
-                        log.debug("   " + entry);
-                    }
-                }
+                logExtensions(bucket);
 
                 result.put(pluginId, bucket);
             } catch (IOException | URISyntaxException e) {
@@ -158,4 +126,21 @@ public class ServiceProviderExtensionFinder extends AbstractExtensionFinder {
         return ServiceProviderExtensionStorage.EXTENSIONS_RESOURCE;
     }
 
+    private Set<String> readExtensions(Path extensionPath) throws IOException {
+        final Set<String> result = new HashSet<>();
+        Files.walkFileTree(extensionPath, Collections.<FileVisitOption>emptySet(), 1, new SimpleFileVisitor<Path>() {
+
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+                log.debug("Read '{}'", file);
+                Reader reader = Files.newBufferedReader(file, StandardCharsets.UTF_8);
+                ServiceProviderExtensionStorage.read(reader, result);
+                return FileVisitResult.CONTINUE;
+            }
+
+        });
+
+        return result;
+    }
+
 }