implemented bridge pattern

structural/bridge/bridge.go

@@ -0,0 +1,37 @@
+package bridge
+
+import "fmt"
+import "errors"
+
+// Bridge interface
+type Drawer interface {
+	DrawRectangle(w, h int) 
+}
+
+type GreenRectangleDrawer struct {}
+func (d GreenRectangleDrawer) DrawRectangle(w, h int) {
+	fmt.Printf("Green rectangle W: %d, H: %d", w, h)
+}
+
+type RedRectangleDrawer struct {}
+func (d RedRectangleDrawer) DrawRectangle(w, h int) {
+	fmt.Printf("Red rectangle W: %d, H: %d", w, h)
+}
+
+type Shape interface {
+	Draw() error
+}
+
+type Rectangle struct {
+	Width, Height int
+	drawer Drawer
+}
+
+func (d Rectangle) Draw () error {
+	if d.drawer == nil {
+		return errors.New("Drawer not initialized.")
+	}
+
+	d.drawer.DrawRectangle(d.Width, d.Height)
+	return nil
+}