From 13f3459476dd59dd0558800e3c26b58aaaa7d125 Mon Sep 17 00:00:00 2001
From: go-to-k <24818752+go-to-k@users.noreply.github.com>
Date: Thu, 5 Sep 2024 16:52:33 +0900
Subject: [PATCH] modify comments and add sample code

---
 .../aws-cdk-lib/aws-cloudwatch/lib/metric.ts  | 30 +++++++++++++++++--
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/packages/aws-cdk-lib/aws-cloudwatch/lib/metric.ts b/packages/aws-cdk-lib/aws-cloudwatch/lib/metric.ts
index 444d1073220af..1db855c817bc5 100644
--- a/packages/aws-cdk-lib/aws-cloudwatch/lib/metric.ts
+++ b/packages/aws-cdk-lib/aws-cloudwatch/lib/metric.ts
@@ -226,9 +226,33 @@ export interface MathExpressionProps extends MathExpressionOptions {
    * The key is the identifier that represents the given metric in the
    * expression, and the value is the actual Metric object.
    *
-   * The `period` of each Metric object is ignored and instead overridden by
-   * the `period` of this math expression object. Even if the `period` of the
-   * math expression is not specified, it is overridden by its default value.
+   * The `period` of each metric in `usingMetrics` is ignored and instead overridden
+   * by the `period` specified for the `MathExpression` construct. Even if no `period`
+   * is specified for the `MathExpression`, it will be overridden by the default
+   * value (`Duration.minutes(5)`).
+   *
+   * Example:
+   *
+   * ```ts
+   * new MathExpression({
+   *   expression:  "m1+m2",
+   *   label: "AlbErrors",
+   *   usingMetrics: {
+   *     m1: metrics.custom("HTTPCode_ELB_500_Count", {
+   *       period: Duration.minutes(1), // <- This period will be ignored
+   *       statistic: "Sum",
+   *       label: "HTTPCode_ELB_500_Count",
+   *     }),
+   *     m2: metrics.custom("HTTPCode_ELB_502_Count", {
+   *       period: Duration.minutes(1), // <- This period will be ignored
+   *       statistic: "Sum",
+   *       label: "HTTPCode_ELB_502_Count",
+   *     }),
+   *   },
+   *   period: Duration.minutes(3), // <- This overrides the period of each metric in `usingMetrics`
+   *                                //    (Even if not specified, it is overridden by the default value)
+   * });
+   * ```
    *
    * @default - Empty map.
    */