From f02429106df3d67efc02d03b9aa6b1a51e06513b Mon Sep 17 00:00:00 2001
From: Yury Semikhatsky <yurys@chromium.org>
Date: Wed, 3 Mar 2021 13:13:59 -0800
Subject: [PATCH] docs: add Page.onceDialog for java (#5706)

---
 docs/src/api/java.md | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/docs/src/api/java.md b/docs/src/api/java.md
index 6a09f45348..fba3bccf85 100644
--- a/docs/src/api/java.md
+++ b/docs/src/api/java.md
@@ -1,3 +1,44 @@
+## method: Page.onceDialog
+* langs: java
+
+Adds one-off [Dialog] handler. The handler will be removed immediately after next [Dialog] is created.
+```java
+page.onceDialog(dialog -> {
+  dialog.accept("foo");
+});
+
+// prints 'foo'
+System.out.println(page.evaluate("prompt('Enter string:')"));
+
+// prints 'null' as the dialog will be auto-dismissed because there are no handlers.
+System.out.println(page.evaluate("prompt('Enter string:')"));
+```
+
+This code above is equivalent to:
+```java
+Consumer<Dialog> handler = new Consumer<Dialog>() {
+  @Override
+  public void accept(Dialog dialog) {
+    dialog.accept("foo");
+    page.offDialog(this);
+  }
+};
+page.onDialog(handler);
+
+// prints 'foo'
+System.out.println(page.evaluate("prompt('Enter string:')"));
+
+// prints 'null' as the dialog will be auto-dismissed because there are no handlers.
+System.out.println(page.evaluate("prompt('Enter string:')"));
+```
+
+### param: Page.onceDialog.handler
+- `handler` <[function]\([Dialog]\)>
+
+Receives the [Dialog] object, it **must** either [`method: Dialog.accept`] or [`method: Dialog.dismiss`] the dialog - otherwise
+the page will [freeze](https://developer.mozilla.org/en-US/docs/Web/JavaScript/EventLoop#never_blocking) waiting for the dialog,
+and actions like click will never finish.
+
 ## method: Playwright.close
 * langs: java