--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-client/src/main/java/de/intevation/flys/client/client/ui/AbstractUIProvider.java	Wed Mar 16 09:57:41 2011 +0000
@@ -0,0 +1,96 @@
+package de.intevation.flys.client.client.ui;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.google.gwt.core.client.GWT;
+
+import com.smartgwt.client.widgets.Canvas;
+import com.smartgwt.client.widgets.events.ClickEvent;
+import com.smartgwt.client.widgets.events.ClickHandler;
+
+import de.intevation.flys.client.client.event.HasStepForwardHandlers;
+import de.intevation.flys.client.client.event.StepForwardEvent;
+import de.intevation.flys.client.client.event.StepForwardHandler;
+import de.intevation.flys.client.shared.model.Data;
+
+
+/**
+ * An abstract UIProvider that provides some basic methods.
+ *
+ * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
+ */
+public abstract class AbstractUIProvider
+implements   UIProvider, HasStepForwardHandlers, ClickHandler
+{
+    /** The StepForwardHandlers.*/
+    protected List<StepForwardHandler> forwardHandlers;
+
+
+    /**
+     * Creates a new UIProvider instance of this class.
+     */
+    public AbstractUIProvider() {
+        forwardHandlers = new ArrayList<StepForwardHandler>();
+    }
+
+
+    /**
+     * Appends a StepForwardHandler that wants to listen to StepForwardEvents.
+     *
+     * @param handler A new StepForwardHandler.
+     */
+    public void addStepForwardHandler(StepForwardHandler handler) {
+        if (handler != null) {
+            forwardHandlers.add(handler);
+        }
+    }
+
+
+    /**
+     * This method is called after the user has clicked on the 'next' button to
+     * step to the next state.
+     *
+     * @param e The StepForwardEvent.
+     */
+    protected void fireStepForwardEvent(StepForwardEvent e) {
+        GWT.log("AbstractUIProvider - fireStepForwardEvent() handlers: " + forwardHandlers.size());
+        for (StepForwardHandler handler: forwardHandlers) {
+            handler.onStepForward(e);
+        }
+    }
+
+
+    /**
+     * This method is used to listen to click events on the 'next' button. The
+     * fireStepForwardEvent() method is called here.
+     *
+     * @param e The click event.
+     */
+    public void onClick(ClickEvent e) {
+        Data[] data = getData();
+
+        fireStepForwardEvent(new StepForwardEvent(data));
+    }
+
+
+    /**
+     * This method needs to be implemented by concrete subclasses. It should
+     * create a new Canvas object with a representation of <i>data</i>.
+     *
+     * @param data The data that should be displayed.
+     *
+     * @return a Canvas object that displays <i>data</i>.
+     */
+    public abstract Canvas create(Data data);
+
+
+    /**
+     * This method needs to be implemented by concrete subclasses. It should
+     * return the selected data.
+     *
+     * @return the selected data.
+     */
+    protected abstract Data[] getData();
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :