sijia-w commented on a change in pull request #7741:
URL: https://github.com/apache/pulsar/pull/7741#discussion_r464977153
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File path: site2/docs/window-functions-context.md
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+---
+id: window-functions-context
+title: Window Functions Context
+sidebar_label: "Window Functions: Context"
+---
+
+Java SDK provides access to a **window context object** that can be used by a
window function. This context object provides a wide variety of information and
functionality for Pulsar window functions as below.
+
+- [Spec](#spec)
+
+ * Names of all input topics and the output topic associated with the
function.
+ * Tenant and namespace associated with the function.
+ * Pulsar window function name, ID, and version.
+ * ID of the Pulsar function instance running the window function.
+ * Number of instances that invoke the window function.
+ * Built-in type or custom class name of the output schema.
+
+- [Logger](#logger)
+
+ * Logger object used by the window function, which can be used to create
window function log messages.
+
+- [User config](#user-config)
+
+ * Access to arbitrary user configuration values.
+
+- [Routing](#routing)
+
+ * Function to publish new messages to arbitrary topics.
+
+- [Metrics](#metrics)
+
+ * Interface for recording metrics.
+
+- [State storage](#state-storage)
+
+ * Interface for storing and retrieving state in [state
storage](#state-storage).
+
+## Spec
+
+Spec contains the basic information of a function.
+
+### Get input topics
+
+`getInputTopics` method gets the **name list** of all input topics.
+
+This example demonstrates how to get the name list of all input topics in a
Java window function.
+
+<!--DOCUSAURUS_CODE_TABS-->
+<!--Java-->
+
+```java
+public class GetInputTopicsWindowFunction implements WindowFunction<String,
Void> {
+ @Override
+ public Void process(Collection<Record<String>> inputs, WindowContext
context) throws Exception {
+ Collection<String> inputTopics = context.getInputTopics();
+ System.out.println(inputTopics);
+
+ return null;
+ }
+
+}
+```
+<!--END_DOCUSAURUS_CODE_TABS-->
+
+### Get output topic
+
+`getOutputTopic` method gets the **name of a topic** to which the message is
sent.
+
+This example demonstrates how to get the name of an output topic in a Java
window function.
+
+<!--DOCUSAURUS_CODE_TABS-->
+<!--Java-->
+
+```java
+public class GetOutputTopicWindowFunction implements WindowFunction<String,
Void> {
+ @Override
+ public Void process(Collection<Record<String>> inputs, WindowContext
context) throws Exception {
+ String outputTopic = context.getOutputTopic();
+ System.out.println(outputTopic);
+
+ return null;
+ }
+}
+```
+<!--END_DOCUSAURUS_CODE_TABS-->
+
+### Get tenant
+
+`getTenant` method gets the tenant name associated with the window function.
+
+This example demonstrates how to get the tenant name in a Java window function.
+
+<!--DOCUSAURUS_CODE_TABS-->
Review comment:
Same here.
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