Text Block Syntax - Deep Dive

We mentioned in the previous post about the subtle difference between the string formed through Text Block syntax and the one formed through regular String syntax. 

Lets examine that through this sample code

public class Main {

    public static void main(String[] args) {
        
        String poemTextBlock = """
                The woods are lovely, dark and deep,   
                But I have promises to keep,   
                And miles to go before I sleep,   
                And miles to go before I sleep.
                """;
        
        String poemString = "The woods are lovely, dark and deep,\n"
                + "But I have promises to keep,\n"
                + "And miles to go before I sleep,\n"
                + "And miles to go before I sleep.";
        
        System.out.println("Text Block: "+poemTextBlock);
        System.out.println("String: "+poemString);
        
        if (poemString.equals(poemTextBlock)) {
            System.out.println("Textblock and String are equal");
        } else {
            System.out.println("Textblock and String are NOT equal");
        }

    }
}.

Here we are comparing the two strings and printing if they are equal or not. 

Output of this code is 

Text Block: The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.

String: The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep.
Textblock and String are NOT equal

Yes. They are not equal. It is due to the new line at the end of the string formed by the Text Block. 

The strings will show as equal when we form the text block string, with the ending three double quotes on the same line as shown below

        String poemTextBlock = """
                The woods are lovely, dark and deep,   
                But I have promises to keep,   
                And miles to go before I sleep,   
                And miles to go before I sleep.""";

This avoids introducing a line terminator (\n) character to the last line of the string. 

But then, what about the first line. Wouldn't the code above introduce a \n before the first line? 

Turns out that the three double-quote and a line terminator marks the beginning of the text block. We cannot start a text block content in the same line as that of the beginning three double quotes. 

Below code would throw a compile time error

        String poemTextBlock = """The woods are lovely, dark and deep,   
                But I have promises to keep,   
                And miles to go before I sleep,   
                And miles to go before I sleep.""";

So a text block begins from the next line of the beginning three double-quotes. And the placement of ending three double-quotes on the same line as the last line of the text block avoids adding a line terminator to the last line. 

What about the spaces used for indentation of the text block content? Would those spaces become part of the text block content? 

We see from the code above that they have not been part of the content in this example. We will explore how the indentation behaves in the text block in our next post.

 

Sample code used in this post can be downloaded from https://github.com/ashokkumarta/awesomely-java/tree/main/2021/03/Language-Features/Text-blocks/Text-Block-Syntax