feat(genai): add thinking samples

[jdomingr]

Description

Add new thinking samples:

• Thinking with text
• Thinking budget with text
• Thinking including thoughts

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• I have followed Sample Format Guide
• Tests pass: mvn clean verify required
• Lint passes: mvn -P lint checkstyle:check required
• Static Analysis: mvn -P lint clean compile pmd:cpd-check spotbugs:check advisory only
• Please merge this PR for me once it is approved

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• genai/snippets/src/main/java/genai/thinking/ThinkingBudgetWithText.java:19, tag googlegenaisdk_thinking_budget_with_txt
• genai/snippets/src/main/java/genai/thinking/ThinkingIncludeThoughtsWithText.java:19, tag googlegenaisdk_thinking_includethoughts_with_txt
• genai/snippets/src/main/java/genai/thinking/ThinkingWithText.java:19, tag googlegenaisdk_thinking_with_txt

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[gemini-code-assist]

Summary of Changes

Hello @jdomingr, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request expands the GenAI SDK Java samples by introducing new examples that showcase various "thinking" functionalities of the generative AI models. These additions provide developers with practical demonstrations of how to control and observe the model's internal thought processes and resource usage when generating text.

Highlights

• New GenAI Thinking Samples: Introduces three new Java samples demonstrating the GenAI SDK's "thinking" capabilities: basic text thinking, thinking with a budget, and thinking with included thoughts.
• Integration Tests: Adds corresponding integration tests to validate the functionality of the new thinking samples.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point in your pull request via creating an issue comment (i.e. comment on the pull request page) using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in issue comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This PR adds new samples for the 'thinking' feature. The code is well-structured, but I have a few suggestions to improve correctness, robustness, and adherence to best practices. My main points are:

• Fixing a potential IndexOutOfBoundsException when processing model responses.
• Improving the way Optional<Boolean> is handled.
• Using a more appropriate method overload to avoid passing null.
• Enhancing an integration test to properly verify the sample's output.
• Using println instead of print for cleaner console output.
  Details are in the line comments.