feat(block-kit): add checkboxes element example

block-kit/README.md

@@ -29,6 +29,7 @@ Read the [docs](https://docs.slack.dev/block-kit/) to learn concepts behind thes
 - **[Broadcast](https://docs.slack.dev/reference/block-kit/block-elements/broadcast-element)**: Displays a broadcast mention such as here, channel, or everyone. [Implementation](./src/main/java/elements/Broadcast.java).
 - **[Button](https://docs.slack.dev/reference/block-kit/block-elements/button-element)**: Allows users a direct path to performing basic actions. [Implementation](./src/main/java/elements/Button.java).
 - **[Channel](https://docs.slack.dev/reference/block-kit/block-elements/channel-element)**: Renders as a mention of a channel. [Implementation](./src/main/java/elements/Channel.java).
+- **[Checkboxes](https://docs.slack.dev/reference/block-kit/block-elements/checkboxes-element)**: Allows users to choose multiple items from a list of options. [Implementation](./src/main/java/elements/Checkboxes.java).
 - **[Color](https://docs.slack.dev/reference/block-kit/block-elements/color-element)**: Displays a color swatch from a hex value. [Implementation](./src/main/java/elements/Color.java).
 - **[Date](https://docs.slack.dev/reference/block-kit/block-elements/date-element)**: Displays a formatted, localized date. [Implementation](./src/main/java/elements/Date.java).
 - **[Date picker](https://docs.slack.dev/reference/block-kit/block-elements/date-picker-element)**: Allows users to select a date from a calendar style UI. [Implementation](./src/main/java/elements/DatePicker.java).

block-kit/src/main/java/elements/Checkboxes.java

@@ -0,0 +1,60 @@
+package elements;
+
+import com.slack.api.model.block.Blocks;
+import com.slack.api.model.block.composition.BlockCompositions;
+import com.slack.api.model.block.composition.OptionObject;
+import com.slack.api.model.block.element.BlockElements;
+import com.slack.api.model.view.View;
+import com.slack.api.model.view.ViewClose;
+import com.slack.api.model.view.ViewSubmit;
+import com.slack.api.model.view.ViewTitle;
+import java.util.List;
+
+/**
+ * Allows users to choose multiple items from a list of options.
+ * {@link https://docs.slack.dev/reference/block-kit/block-elements/checkboxes-element/}
+ */
+public class Checkboxes {
+    /**
+     * A section block containing a group of checkboxes.
+     */
+    public static View example01() {
+        View view = View.builder()
+                .type("modal")
+                .title(ViewTitle.builder()
+                        .type("plain_text")
+                        .text("My App")
+                        .emoji(true)
+                        .build())
+                .submit(ViewSubmit.builder()
+                        .type("plain_text")
+                        .text("Submit")
+                        .emoji(true)
+                        .build())
+                .close(ViewClose.builder()
+                        .type("plain_text")
+                        .text("Cancel")
+                        .emoji(true)
+                        .build())
+                .blocks(List.of(Blocks.section(s -> s.text(
+                                BlockCompositions.plainText("Check out these charming checkboxes"))
+                        .accessory(BlockElements.checkboxes(c -> c.actionId("this_is_an_action_id")
+                                .initialOptions(List.of(OptionObject.builder()
+                                        .value("A1")
+                                        .text(BlockCompositions.plainText("Checkbox 1"))
+                                        .build()))
+                                .options(List.of(
+                                        OptionObject.builder()
+                                                .value("A1")
+                                                .text(BlockCompositions.plainText("Checkbox 1"))
+                                                .build(),
+                                        OptionObject.builder()
+                                                .value("A2")
+                                                .text(BlockCompositions.plainText("Checkbox 2"))
+                                                .description(
+                                                        BlockCompositions.markdownText("*A description of option two*"))
+                                                .build())))))))
+                .build();
+        return view;
+    }
+}

block-kit/src/test/java/elements/CheckboxesTest.java

@@ -0,0 +1,79 @@
+package elements;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.google.gson.JsonParser;
+import com.slack.api.model.view.View;
+import com.slack.api.util.json.GsonFactory;
+import org.junit.jupiter.api.Test;
+
+public class CheckboxesTest {
+    @Test
+    public void testExample01() {
+        View view = Checkboxes.example01();
+        String actual = GsonFactory.createSnakeCase().toJson(view);
+        String expected = """
+            {
+              "type": "modal",
+              "title": {
+                "type": "plain_text",
+                "text": "My App",
+                "emoji": true
+              },
+              "submit": {
+                "type": "plain_text",
+                "text": "Submit",
+                "emoji": true
+              },
+              "close": {
+                "type": "plain_text",
+                "text": "Cancel",
+                "emoji": true
+              },
+              "blocks": [
+                {
+                  "type": "section",
+                  "text": {
+                    "type": "plain_text",
+                    "text": "Check out these charming checkboxes"
+                  },
+                  "accessory": {
+                    "type": "checkboxes",
+                    "action_id": "this_is_an_action_id",
+                    "initial_options": [
+                      {
+                        "value": "A1",
+                        "text": {
+                          "type": "plain_text",
+                          "text": "Checkbox 1"
+                        }
+                      }
+                    ],
+                    "options": [
+                      {
+                        "value": "A1",
+                        "text": {
+                          "type": "plain_text",
+                          "text": "Checkbox 1"
+                        }
+                      },
+                      {
+                        "value": "A2",
+                        "text": {
+                          "type": "plain_text",
+                          "text": "Checkbox 2"
+                        },
+                        "description": {
+                          "type": "mrkdwn",
+                          "text": "*A description of option two*"
+                        }
+                      }
+                    ]
+                  }
+                }
+              ]
+            }
+            """;
+        assertEquals(JsonParser.parseString(expected), JsonParser.parseString(actual));
+    }
+}