--- /dev/null
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ * VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+/*\r
+ *\r
+ * @author Toni Kalajainen\r
+ */\r
+package org.simantics.scenegraph.g2d.events;\r
+\r
+import java.lang.annotation.ElementType;\r
+import java.lang.annotation.Retention;\r
+import java.lang.annotation.RetentionPolicy;\r
+import java.lang.annotation.Target;\r
+import java.lang.reflect.InvocationTargetException;\r
+import java.lang.reflect.Method;\r
+import java.util.ArrayList;\r
+import java.util.List;\r
+\r
+/**\r
+ * @author Toni Kalajainen\r
+ */\r
+public class EventHandlerReflection {\r
+\r
+ @Retention(RetentionPolicy.RUNTIME)\r
+ @Target(ElementType.METHOD)\r
+ public static @interface EventHandler {\r
+ int priority();\r
+ }\r
+\r
+ /**\r
+ * Scans an object with reflection for all event handler methods and returns\r
+ * an array of IEventHandler and priorities.\r
+ * <p>\r
+ * The corresponding class of obj must contain methods that meet the\r
+ * following criteria: 1) must return boolean 2) 1 argument, which is Event\r
+ * 3) has annotation EventHandler 4) may not throw any Exception 5) method\r
+ * must be accessible\r
+ * <p>\r
+ * Example:\r
+ * \r
+ * @EventHandler(priority = Integer.MAX_VALUE) public boolean\r
+ * handleEvent(Event e) { return false; }\r
+ * \r
+ * @param obj object to scan\r
+ * @return an array of painters and their priorities\r
+ */\r
+ @SuppressWarnings("unchecked")\r
+ public static EventHandlerDefinition[] getEventHandlers(final Object obj) {\r
+ List<EventHandlerDefinition> result = new ArrayList<EventHandlerDefinition>();\r
+ Class<?> clazz = obj.getClass();\r
+\r
+ for (final Method m : clazz.getMethods()) {\r
+ EventHandler anno = (EventHandler) m.getAnnotation(EventHandler.class);\r
+ if (anno == null)\r
+ continue;\r
+\r
+ Class<?> returnType = m.getReturnType();\r
+ if (!returnType.equals(boolean.class))\r
+ throw new RuntimeException(clazz.getName() + "." + m.getName() + " return type is invalid");\r
+\r
+ @SuppressWarnings("rawtypes")\r
+ Class[] argTypes = m.getParameterTypes();\r
+ if (argTypes.length != 1 || !Event.class.isAssignableFrom(argTypes[0]))\r
+ throw new RuntimeException(clazz.getName() + "." + m.getName() + " invalid arguments");\r
+\r
+ @SuppressWarnings("rawtypes")\r
+ Class argClass = argTypes[0];\r
+\r
+ @SuppressWarnings("rawtypes")\r
+ Class[] exceptionTypes = m.getExceptionTypes();\r
+ if (exceptionTypes.length != 0)\r
+ throw new RuntimeException(clazz.getName() + "." + m.getName() + " invalid exceptions");\r
+\r
+ int priority = anno.priority();\r
+\r
+ try {\r
+ m.setAccessible(true);\r
+ } catch (Throwable t) {\r
+ t.printStackTrace();\r
+ continue;\r
+ }\r
+\r
+ final int eventMask = EventTypes.toTypeMask(argClass);\r
+\r
+ IEventHandler eventHandler = new IEventHandler() {\r
+ @Override\r
+ public int getEventMask() {\r
+ return eventMask;\r
+ }\r
+ @Override\r
+ public boolean handleEvent(Event e1) {\r
+ try {\r
+ return (Boolean) m.invoke(obj, e1);\r
+ } catch (IllegalArgumentException e) {\r
+ throw new Error(e);\r
+ } catch (IllegalAccessException e) {\r
+ throw new RuntimeException(e);\r
+ } catch (InvocationTargetException e) {\r
+ throw new RuntimeException(e);\r
+ }\r
+ }\r
+ };\r
+ EventHandlerDefinition handler = new EventHandlerDefinition(obj, eventHandler, priority, argClass);\r
+ result.add(handler);\r
+ }\r
+\r
+ return result.toArray(new EventHandlerDefinition[0]);\r
+ }\r
+\r
+ public final static class EventHandlerDefinition {\r
+ public final Object obj;\r
+ public final IEventHandler origEventHandler;\r
+ public final IEventHandler eventHandler;\r
+ public final int priority;\r
+ public final Class<Event> eventSuperClass;\r
+\r
+ public EventHandlerDefinition(Object obj, IEventHandler eventHandler, int priority, Class<Event> eventSuperClass) {\r
+ this.obj = obj;\r
+ this.priority = priority;\r
+ this.eventSuperClass = eventSuperClass;\r
+ this.origEventHandler = eventHandler;\r
+ final int eventMask = EventTypes.toTypeMask(eventSuperClass);\r
+ if (eventSuperClass.equals(Event.class)) {\r
+ this.eventHandler = eventHandler;\r
+ } else {\r
+ this.eventHandler = new IEventHandler() {\r
+ @Override\r
+ public int getEventMask() {\r
+ return eventMask;\r
+ }\r
+\r
+ @Override\r
+ public boolean handleEvent(Event e) {\r
+ // Event masking already taken care of, no need to check eventMask\r
+ if (EventHandlerDefinition.this.eventSuperClass.isAssignableFrom(e.getClass()))\r
+ return EventHandlerDefinition.this.origEventHandler.handleEvent(e);\r
+ return false;\r
+ }\r
+\r
+ @Override\r
+ public String toString() {\r
+ return EventHandlerDefinition.this.toString();\r
+ }\r
+ };\r
+ }\r
+ }\r
+\r
+ @Override\r
+ public String toString() {\r
+ return String.format("[%11d] %s (%s)", priority, obj.getClass().getSimpleName(),\r
+ eventSuperClass.getSimpleName());\r
+ }\r
+ }\r
+\r
+}\r
Code Review / simantics / platform.git / blobdiff