Java StringTemplate combine() Method

The StringTemplate.combine() method in Java 21 is used to combine multiple StringTemplate instances into a single StringTemplate. This guide will cover the method's usage, explain how it works, and provide examples to demonstrate its functionality.

Table of Contents

1. Introduction
2. combine() Method Syntax
3. Understanding combine()
4. Examples
   • Basic Usage
   • Combining Multiple Templates
5. Real-World Use Case
6. Conclusion

Introduction

The StringTemplate.combine() method is part of the new StringTemplate API introduced in Java 21. This method allows developers to combine multiple StringTemplate instances into a single cohesive StringTemplate, which can be useful for building dynamic content.

combine() Method Syntax

The syntax for the combine() method is as follows:

public static StringTemplate combine(StringTemplate... templates)

Parameters:

• templates: A varargs parameter representing multiple StringTemplate instances to be combined.

Returns:

• A single StringTemplate that is the result of combining the given string templates.

Understanding combine()

The combine() method takes multiple StringTemplate instances and combines their content into a single StringTemplate. This is particularly useful when you need to dynamically construct complex templates from various parts.

Examples

Basic Usage

To demonstrate the basic usage of combine(), we will create a simple example where we combine two string templates.

Example

import java.lang.StringTemplate;

public class StringTemplateCombineExample {
    public static void main(String[] args) {
        StringTemplate template1 = StringTemplate.of("Hello, ");
        StringTemplate template2 = StringTemplate.of("World!");

        StringTemplate combined = StringTemplate.combine(template1, template2);
        System.out.println(combined.interpolate());
    }
}

Output:

Hello, World!

Combining Multiple Templates

You can use the combine() method to combine multiple string templates into a single StringTemplate.

Example

import java.lang.StringTemplate;

public class MultipleStringTemplatesExample {
    public static void main(String[] args) {
        StringTemplate greeting = StringTemplate.of("Hello, ");
        StringTemplate name = StringTemplate.of("Alice");
        StringTemplate exclamation = StringTemplate.of("!");

        StringTemplate combined = StringTemplate.combine(greeting, name, exclamation);
        System.out.println(combined.interpolate());
    }
}

Output:

Hello, Alice!

Real-World Use Case

Building Dynamic HTML Content

In web development, you might need to build dynamic HTML content based on various templates. Using StringTemplate.combine(), you can combine different parts of an HTML page into a single cohesive StringTemplate.

Example

import java.lang.StringTemplate;

public class DynamicHtmlContentExample {
    public static void main(String[] args) {
        StringTemplate header = StringTemplate.of("<header><h1>Welcome to My Website</h1></header>");
        StringTemplate body = StringTemplate.of("<main><p>This is the main content of the website.</p></main>");
        StringTemplate footer = StringTemplate.of("<footer><p>&copy; 2024 My Website</p></footer>");

        StringTemplate htmlContent = StringTemplate.combine(header, body, footer);
        System.out.println(htmlContent.interpolate());
    }
}

Output:

<header><h1>Welcome to My Website</h1></header>
<main><p>This is the main content of the website.</p></main>
<footer><p>&copy; 2024 My Website</p></footer>

Conclusion

The StringTemplate.combine() method in Java 21 provides a powerful way to combine multiple StringTemplate instances into a single StringTemplate. By using this method, you can dynamically construct complex templates from various parts, making it easier to build dynamic content for applications. 

Whether you are working with simple string templates or complex dynamic content, the StringTemplate.combine() method offers a reliable tool for managing and combining string templates.