Add support for simplified RPC communication with JS code (#8888)

1 files changed, 55 insertions, 0 deletions

diff --git a/src/com/vaadin/terminal/JavascriptRpcHelper.java b/src/com/vaadin/terminal/JavascriptRpcHelper.java
new file mode 100644
index 0000000000..f6607e557f
--- /dev/null
+++ b/src/com/vaadin/terminal/JavascriptRpcHelper.java
@@ -0,0 +1,55 @@
+/* 
+@VaadinApache2LicenseForJavaFiles@
+ */
+
+package com.vaadin.terminal;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import com.vaadin.external.json.JSONArray;
+import com.vaadin.tools.ReflectTools;
+import com.vaadin.ui.JavascriptCallback;
+import com.vaadin.ui.JavascriptManager.JavascriptCallbackRpc;
+
+public class JavascriptRpcHelper {
+
+    private static final Method CALL_METHOD = ReflectTools.findMethod(
+            JavascriptCallbackRpc.class, "call", String.class, JSONArray.class);
+    private AbstractClientConnector connector;
+
+    private Map<String, JavascriptCallback> callbacks = new HashMap<String, JavascriptCallback>();
+    private JavascriptCallbackRpc javascriptCallbackRpc;
+
+    public JavascriptRpcHelper(AbstractClientConnector connector) {
+        this.connector = connector;
+    }
+
+    public void registerRpc(JavascriptCallback javascriptCallback,
+            String functionName) {
+        callbacks.put(functionName, javascriptCallback);
+        ensureRpc();
+    }
+
+    private void ensureRpc() {
+        if (javascriptCallbackRpc == null) {
+            javascriptCallbackRpc = new JavascriptCallbackRpc() {
+                public void call(String name, JSONArray arguments) {
+                    JavascriptCallback callback = callbacks.get(name);
+                    callback.call(arguments);
+                }
+            };
+            connector.registerRpc(javascriptCallbackRpc);
+        }
+    }
+
+    public void callRpcFunction(String name, Object... arguments) {
+        JSONArray args = new JSONArray(Arrays.asList(arguments));
+        connector.addMethodInvocationToQueue(
+                JavascriptCallbackRpc.class.getName(), CALL_METHOD,
+                new Object[] { name, args });
+    }
+
+}