updated events, event handlers, window class, demo.

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemCharEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemCharEvent implements SystemEvent {
+public class SystemCharEvent extends SystemEvent {
 
     public final long window;
     public final int codePoint;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemCharModsEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemCharModsEvent implements SystemEvent {
+public class SystemCharModsEvent extends SystemEvent {
 
     public final long window;
     public final int codePoint;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemCursorEnterEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemCursorEnterEvent implements SystemEvent {
+public class SystemCursorEnterEvent extends SystemEvent {
 
     public final long window;
     public final boolean entered;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemCursorPosEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemCursorPosEvent implements SystemEvent {
+public class SystemCursorPosEvent extends SystemEvent {
 
     public final long window;
     public final double posX;
@@ -15,8 +15,8 @@ public SystemCursorPosEvent(long window, double posX, double posY) {
         this.window = window;
         this.posX = posX;
         this.posY = posY;
-        fx = (float) posX;
-        fy = (float) posY;
+        this.fx = (float) posX;
+        this.fy = (float) posY;
     }
 
     @Override

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemDropEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemDropEvent implements SystemEvent {
+public class SystemDropEvent extends SystemEvent {
 
     public final long window;
     public final String[] strings;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemEvent.java

@@ -1,8 +1,24 @@
 package com.spinyowl.spinygui.backend.core.event;
 
+import com.spinyowl.spinygui.backend.core.event.handler.SystemEventHandler;
+import com.spinyowl.spinygui.backend.core.event.handler.SystemEventHandlers;
+
 /**
  * Marker interface that defines tree of system events.
  */
-public interface SystemEvent {
+public abstract class SystemEvent {
+
+    private final SystemEventHandler eventHandler;
+
+    public SystemEvent(SystemEventHandler systemEventHandler) {
+        this.eventHandler = systemEventHandler;
+    }
+
+    public SystemEvent() {
+        this.eventHandler = SystemEventHandlers.getHandler(getClass());
+    }
 
+    public SystemEventHandler getEventHandler() {
+        return eventHandler;
+    }
 }

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemFramebufferSizeEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemFramebufferSizeEvent implements SystemEvent {
+public class SystemFramebufferSizeEvent extends SystemEvent {
 
     public final long window;
     public final int width;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemKeyEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemKeyEvent implements SystemEvent {
+public class SystemKeyEvent extends SystemEvent {
 
     public final long window;
     public final int key;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemMouseClickEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemMouseClickEvent implements SystemEvent {
+public class SystemMouseClickEvent extends SystemEvent {
 
     public final long window;
     public final int button;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemScrollEvent.java

@@ -3,7 +3,7 @@
 import org.apache.commons.lang3.builder.ToStringBuilder;
 import org.apache.commons.lang3.builder.ToStringStyle;
 
-public class SystemScrollEvent implements SystemEvent {
+public class SystemScrollEvent extends SystemEvent {
 
     public final long window;
     public final double offsetX;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowCloseEvent.java

@@ -1,12 +1,14 @@
 package com.spinyowl.spinygui.backend.core.event;
 
+import com.spinyowl.spinygui.backend.core.event.handler.SystemEventHandlers;
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowCloseEvent implements SystemEvent {
+public class SystemWindowCloseEvent extends SystemEvent {
 
     public final long window;
 
     public SystemWindowCloseEvent(long window) {
+        super(SystemEventHandlers.getSystemWindowCloseEventHandler());
         this.window = window;
     }
 

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowContentScaleEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowContentScaleEvent implements SystemEvent {
+public class SystemWindowContentScaleEvent extends SystemEvent {
     public final long window;
     public final float scaleX;
     public final float scaleY;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowFocusEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowFocusEvent implements SystemEvent {
+public class SystemWindowFocusEvent extends SystemEvent {
 
     public final long window;
     public final boolean focused;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowIconifyEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowIconifyEvent implements SystemEvent {
+public class SystemWindowIconifyEvent extends SystemEvent {
 
     public final long window;
     public final boolean iconified;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowMaximizeEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowMaximizeEvent implements SystemEvent {
+public class SystemWindowMaximizeEvent extends SystemEvent {
     public final long window;
     public final boolean maximized;
 

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowPosEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowPosEvent implements SystemEvent {
+public class SystemWindowPosEvent extends SystemEvent {
 
     public final long window;
     public final int posX;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowRefreshEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowRefreshEvent implements SystemEvent {
+public class SystemWindowRefreshEvent extends SystemEvent {
 
     public final long window;
 

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/SystemWindowSizeEvent.java

@@ -2,7 +2,7 @@
 
 import org.apache.commons.lang3.builder.ToStringBuilder;
 
-public class SystemWindowSizeEvent implements SystemEvent {
+public class SystemWindowSizeEvent extends SystemEvent {
 
     public final long window;
     public final int width;

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/handler/SystemCursorPosEventHandler.java

@@ -0,0 +1,13 @@
+package com.spinyowl.spinygui.backend.core.event.handler;
+
+import com.spinyowl.spinygui.backend.core.event.SystemCursorPosEvent;
+import com.spinyowl.spinygui.core.system.service.ServiceHolder;
+
+public class SystemCursorPosEventHandler implements SystemEventHandler<SystemCursorPosEvent> {
+    @Override
+    public void handle(SystemCursorPosEvent event) {
+//        ServiceHolder.
+
+
+    }
+}

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/handler/SystemEventHandlers.java

@@ -0,0 +1,44 @@
+package com.spinyowl.spinygui.backend.core.event.handler;
+
+import com.spinyowl.spinygui.backend.core.event.SystemEvent;
+import com.spinyowl.spinygui.backend.core.event.SystemWindowCloseEvent;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class SystemEventHandlers {
+
+    public static final SystemEventHandler<SystemWindowCloseEvent> DEFAULT_SYSTEM_WINDOW_CLOSE_EVENT_HANDLER = new SystemWindowCloseEventHandler();
+    private static SystemEventHandler<SystemWindowCloseEvent> systemWindowCloseEventHandler = DEFAULT_SYSTEM_WINDOW_CLOSE_EVENT_HANDLER;
+
+    private static Map<Class<? extends SystemEvent>, SystemEventHandler> eventHandlerMap = new ConcurrentHashMap<>();
+
+    static {
+        setHandler(SystemWindowCloseEvent.class, systemWindowCloseEventHandler);
+    }
+
+    private SystemEventHandlers() {
+    }
+
+    public static <T extends SystemEvent, H extends SystemEventHandler<T>> void setHandler(Class<T> clazz, H handler) {
+        eventHandlerMap.put(clazz, handler);
+    }
+
+    public static <T extends SystemEvent> SystemEventHandler<T> getHandler(Class<T> clazz) {
+        return (SystemEventHandler<T>) eventHandlerMap.get(clazz);
+    }
+
+    public static SystemEventHandler<SystemWindowCloseEvent> getSystemWindowCloseEventHandler() {
+        return systemWindowCloseEventHandler;
+    }
+
+    public static void setSystemWindowCloseEventHandler(SystemEventHandler<SystemWindowCloseEvent> systemWindowCloseEventHandler) {
+        if (systemWindowCloseEventHandler != null) {
+            SystemEventHandlers.systemWindowCloseEventHandler = systemWindowCloseEventHandler;
+        } else {
+            SystemEventHandlers.systemWindowCloseEventHandler = DEFAULT_SYSTEM_WINDOW_CLOSE_EVENT_HANDLER;
+        }
+        setHandler(SystemWindowCloseEvent.class, SystemEventHandlers.systemWindowCloseEventHandler);
+    }
+
+}

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/handler/SystemWindowCloseEventHandler.java

@@ -3,7 +3,7 @@
 import com.spinyowl.spinygui.backend.core.event.SystemWindowCloseEvent;
 import com.spinyowl.spinygui.core.event.WindowCloseEvent;
 import com.spinyowl.spinygui.core.event.processor.EventProcessor;
-import com.spinyowl.spinygui.core.service.ServiceHolder;
+import com.spinyowl.spinygui.core.system.service.ServiceHolder;
 
 public class SystemWindowCloseEventHandler implements SystemEventHandler<SystemWindowCloseEvent> {
     @Override

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/handler/util/SehUtil.java

@@ -0,0 +1,89 @@
+package com.spinyowl.spinygui.backend.core.event.handler.util;
+
+import com.spinyowl.spinygui.core.component.base.Component;
+import com.spinyowl.spinygui.core.component.base.Container;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public final class SehUtil {
+
+    private SehUtil() {
+    }
+
+    /**
+     * Used to find target component for provided layer and vector. Target means top component which intersected by provided point(vector).
+     *
+     * @param container root container to search.
+     * @param x         x point coordinates to search.
+     * @param y         y point coordinates to search.
+     * @return top component from layer intersected by vector.
+     */
+    public static Component getTargetComponent(Container container, final float x, final float y) {
+        Component target = container;
+        List<Component> childComponents = container.getChildComponents();
+        for (Component child : childComponents) {
+            target = recursiveTargetComponentSearch(child, target, x, y);
+        }
+        return target;
+    }
+
+    /**
+     * Used to search target component (under point) in component. Target means top component which intersected by provided point(vector).
+     *
+     * @param component source component to search target.
+     * @param target    current target.
+     * @param x         x point coordinates to search.
+     * @param y         y point coordinates to search.
+     * @return the top visible component under point.
+     */
+    private static Component recursiveTargetComponentSearch(Component component, Component target, final float x, final float y) {
+        Component newtarget = target;
+        if (isaTarget(component, x, y)) {
+            newtarget = component;
+            List<Component> childComponents = component.getChildComponents();
+            for (Component child : childComponents) {
+                newtarget = recursiveTargetComponentSearch(child, newtarget, x, y);
+            }
+        }
+        return newtarget;
+    }
+
+
+    /**
+     * Used to search all components (under point) in component.
+     *
+     * @param container root container to search.
+     * @param x         x point coordinates to search.
+     * @param y         y point coordinates to search.
+     * @return all top visible components in layer under point(vector).
+     */
+    public static List<Component> getTargetComponentList(Container container, final float x, final float y) {
+        List<Component> targetList = new ArrayList<>();
+        recursiveTargetComponentListSearch(container, targetList, x, y);
+        return targetList;
+    }
+
+
+    /**
+     * Used to search all components (under point) in component. New located target component will be added to target list.
+     *
+     * @param component  source component to search target.
+     * @param targetList current target list.
+     * @param x          x point coordinates to search.
+     * @param y          y point coordinates to search.
+     */
+    public static void recursiveTargetComponentListSearch(Component component, List<Component> targetList, final float x, final float y) {
+        if (isaTarget(component, x, y)) {
+            targetList.add(component);
+            List<Component> childComponents = component.getChildComponents();
+            for (Component child : childComponents) {
+                recursiveTargetComponentListSearch(child, targetList, x, y);
+            }
+        }
+    }
+
+    private static boolean isaTarget(Component component, float x, float y) {
+        return component.isVisible() && component.getIntersection().intersects(component, x, y);
+    }
+}

backend.core/src/main/java/com/spinyowl/spinygui/backend/core/event/processor/DefaultSystemEventProcessor.java

@@ -14,11 +14,6 @@
 public class DefaultSystemEventProcessor extends SystemEventProcessor {
 
     private Queue<SystemEvent> eventQueue = new LinkedBlockingQueue<>();
-    private Map<Class<? extends SystemEvent>, SystemEventHandler<? extends SystemEvent>> eventHandlerMap = new ConcurrentHashMap<>();
-
-    {
-        setHandler(SystemWindowCloseEvent.class, new SystemWindowCloseEventHandler());
-    }
 
     @Override
     public void pushEvent(SystemEvent event) {
@@ -36,18 +31,12 @@ public void processEvents() {
 
 
     private void processEvent(SystemEvent event) {
-        SystemEventHandler handler = getHandler(event.getClass());
+        SystemEventHandler handler = event.getEventHandler();
         if (handler != null) {
             System.out.println("PROCESS EVENT: " + event);
             handler.handle(event);
         }
     }
 
-    public <T extends SystemEvent, H extends SystemEventHandler<T>> void setHandler(Class<T> clazz, H handler) {
-        eventHandlerMap.put(clazz, handler);
-    }
 
-    public <T extends SystemEvent, H extends SystemEventHandler<T>> H getHandler(Class<T> clazz) {
-        return (H) eventHandlerMap.get(clazz);
-    }
 }

backend.glfwutil/src/main/java/com/spinyowl/spinygui/backend/glfwutil/callback/DefaultCallback.java

@@ -2,7 +2,6 @@
 
 import com.spinyowl.spinygui.backend.core.event.*;
 import com.spinyowl.spinygui.backend.core.event.processor.SystemEventProcessor;
-import com.spinyowl.spinygui.core.service.ServiceHolder;
 import org.lwjgl.PointerBuffer;
 import org.lwjgl.glfw.*;