1 files changed, 114 insertions, 0 deletions
diff --git a/src/com/vaadin/terminal/gwt/client/ComponentEventHandler.java b/src/com/vaadin/terminal/gwt/client/ComponentEventHandler.java
new file mode 100644
index 0000000000..f309f79979
--- /dev/null
+++ b/src/com/vaadin/terminal/gwt/client/ComponentEventHandler.java
@@ -0,0 +1,114 @@
+/* 
+@ITMillApache2LicenseForJavaFiles@
+ */
+
+package com.vaadin.terminal.gwt.client;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 
+ * class for event handlers used by ComponentEventHandler
+ * 
+ * @author davengo GmbH (Germany/Berlin, www.davengo.com)
+ * 
+ */
+public class ComponentEventHandler {
+
+    public static final String HANDLER_LISTEN_ATTRIBUTE = "listenEvents";
+    public static final String HANDLER_TRIGGER_VARIABLE = "fireEvent";
+
+    private List<String> eventRegistrations;
+    private ComponentDetail detail;
+    private ApplicationConnection client;
+
+    public ComponentEventHandler(ComponentDetail detail,
+            ApplicationConnection client) {
+        this.detail = detail;
+        this.client = client;
+        this.eventRegistrations = null;
+    }
+
+    /**
+     * Fires a event which is transmitted to the server and passed on the the
+     * components handleEvent method provided listeners have been registered on
+     * the server side.
+     * 
+     * @param eventIdentifier
+     *            the unique identifier for the event
+     * @param parameters
+     *            the parameters for the event (can be null)
+     */
+    public void fireEvent(String eventIdentifier, String... parameters) {
+        fireEvent(eventIdentifier, false, parameters);
+    }
+
+    /**
+     * Fires a component event which is transmitted to the server and passed on
+     * the the components handleEvent method. The event is sent to the server
+     * even though there are no explicit listeners registered on the server
+     * side.
+     * 
+     * @param eventIdentifier
+     *            the unique identifier for the event
+     * @param parameters
+     *            the parameters for the event (can be null)
+     */
+    public void fireComponentEvent(String eventIdentifier, String... parameters) {
+        fireEvent(eventIdentifier, true, parameters);
+    }
+
+    private void fireEvent(String eventIdentifier, boolean forceTransmission,
+            String... parameters) {
+
+        String[] event;
+
+        // filter events which are not listened on the server-side right here
+        boolean transmit = forceTransmission
+                || ((!(eventRegistrations == null)) && eventRegistrations
+                        .contains(eventIdentifier));
+
+        if (transmit) {
+            if (parameters != null) {
+                event = new String[parameters.length + 1];
+                event[0] = eventIdentifier;
+                for (int i = 0; i < parameters.length; i++) {
+                    event[i + 1] = parameters[i];
+                }
+            } else {
+                event = new String[] { eventIdentifier };
+            }
+
+            // transmit the event to the server-side
+            client.updateVariable(detail.getPid(), HANDLER_TRIGGER_VARIABLE,
+                    event, true);
+        }
+    }
+
+    void registerEventsFromUIDL(UIDL componentUIDL) {
+
+        // read out the request event handlers
+        if (componentUIDL.hasAttribute(HANDLER_LISTEN_ATTRIBUTE)) {
+            String[] requestedEvents = componentUIDL
+                    .getStringArrayAttribute(HANDLER_LISTEN_ATTRIBUTE);
+
+            // create the eventRegistrations list if necessary
+            if ((requestedEvents.length > 0) && (eventRegistrations == null)) {
+                eventRegistrations = new ArrayList<String>();
+            }
+
+            // parse the requested event handlers
+            for (String reqEvent : requestedEvents) {
+
+                if (!eventRegistrations.contains(reqEvent)) {
+                    eventRegistrations.add(reqEvent);
+                }
+
+            }
+
+        }
+
+    }
+
+}