Text Blocks

// ── Basic text block ─────────────────────────────────────────────────
String json = """
        {
            "name": "Alice",
            "age": 30,
            "active": true
        }
        """;
// Equivalent to:
// "{\n    \"name\": \"Alice\",\n    \"age\": 30,\n    \"active\": true\n}\n"

// ── Indentation stripping — closing delimiter controls indent ──────────
// The closing """ is at column 8 (8 spaces from left margin)
// Java strips 8 spaces from EVERY line's leading whitespace

String sql = """
        SELECT id, name, email
        FROM users
        WHERE active = true
        ORDER BY name
        """;
// Leading 8 spaces stripped — result has NO leading spaces:
// "SELECT id, name, email\nFROM users\nWHERE active = true\nORDER BY name\n"

// ── Closing delimiter position controls trailing newline ───────────────
// Closing """ on its own line → string ENDS with \n
String withNewline = """
        Hello
        World
        """;   // ← """ on its own line: ends with \n

// Closing """ on last content line → NO trailing \n
String noNewline = """
        Hello
        World"""; // ← """ on content line: no trailing \n

System.out.println(withNewline.endsWith("\n"));  // true
System.out.println(noNewline.endsWith("\n"));    // false

// ── Alignment of closing delimiter affects content indentation ─────────
// Closing """ further left than content → extra spaces in result
String extraIndent = """
            line one
            line two
        """;  // closing at column 8, content at column 12 → 4 leading spaces per line
// "    line one\n    line two\n"

// ── Standard escapes work inside text blocks ─────────────────────────
String withTab = """
        Column1\tColumn2\tColumn3
        value1\tvalue2\tvalue3
        """;

// ── \<newline> — suppress line break in the source ────────────────────
// This SQL appears on three source lines but is one logical line:
String sql = """
        SELECT id, name, email FROM users \
        WHERE active = true AND age > 18 \
        ORDER BY name LIMIT 100
        """;
// Result: "SELECT id, name, email FROM users WHERE active = true AND age > 18 ORDER BY name LIMIT 100\n"
// (The \ at end of each line suppresses the newline)

// ── \s — preserve trailing space ──────────────────────────────────────
// Without \s, trailing spaces are stripped:
String noTrail = """
        line one     
        line two     
        """;
// "line one\nline two\n" — trailing spaces removed

// With \s, space before \s is preserved:
String withTrail = """
        line one    \s
        line two    \s
        """;
// "line one     \nline two     \n" — five trailing spaces preserved on each line

// ── Double quotes do NOT need escaping inside text blocks ─────────────
String html = """
        <a href="https://example.com" class="link">
            Click "here" to continue
        </a>
        """;
// No escaping needed for " — major readability improvement over regular strings

// ── Triple quote inside text block — escape one quote in the run ──────
// Option 1: escape the first quote
String code = """
        String msg = \"""Hello\""";
        """;

// Option 2: escape the last quote of each run
String code2 = """
        String msg = ""\"Hello""\";
        """;
// Both produce: String msg = """Hello""";

// ── Before vs after text blocks — JSON comparison ─────────────────────
// Before (Java 14 and earlier):
String jsonOld = "{\n" +
    "    \"name\": \"Alice\",\n" +
    "    \"age\": 30,\n" +
    "    \"active\": true\n" +
    "}";

// After (Java 15+):
String jsonNew = """
        {
            "name": "Alice",
            "age": 30,
            "active": true
        }
        """;

// ── SQL with text block ──────────────────────────────────────────────
String findActiveUsers = """
        SELECT
            u.id,
            u.name,
            u.email,
            COUNT(o.id) AS order_count
        FROM users u
        LEFT JOIN orders o ON o.user_id = u.id
        WHERE u.active = true
          AND u.created_at > :cutoffDate
        GROUP BY u.id, u.name, u.email
        HAVING COUNT(o.id) > :minOrders
        ORDER BY order_count DESC
        """;

// ── HTML template ─────────────────────────────────────────────────────
String emailTemplate = """
        <!DOCTYPE html>
        <html>
        <body>
            <h1>Welcome, %s!</h1>
            <p>Your account has been created.</p>
            <p>Click <a href="%s">here</a> to verify.</p>
        </body>
        </html>
        """;

// ── formatted() — substitute values into text block ───────────────────
String email = emailTemplate.formatted("Alice", "https://example.com/verify/abc123");

// ── JSON payload ──────────────────────────────────────────────────────
String createUserBody = """
        {
            "username": "%s",
            "email": "%s",
            "role": "USER",
            "active": true
        }
        """.formatted(username, email);

// ── YAML configuration ────────────────────────────────────────────────
String yamlConfig = """
        server:
          port: %d
          host: %s
        database:
          url: %s
          pool-size: %d
        """.formatted(port, host, dbUrl, poolSize);

// ── Test assertions — expected multi-line output ───────────────────────
@Test
void formatReport_producesExpectedLayout() {
    String expected = """
            ID   Name          Score
            --   ----          -----
            1    Alice         95
            2    Bob           87
            """;
    String actual = formatter.formatReport(testData);
    assertThat(actual).isEqualTo(expected);
}

// ── stripIndent() and translateEscapes() — programmatic manipulation ──
// stripIndent() applies the text block re-indentation algorithm to a runtime string
String indented = "    line1\n    line2\n    line3\n";
String stripped = indented.stripIndent();
System.out.println(stripped);   // "line1\nline2\nline3\n"

// translateEscapes() interprets \n, \t etc. in a runtime string
String withEscapes = "line1\\nline2\\nline3";
System.out.println(withEscapes.translateEscapes());  // prints on three lines

// ── Mistake 1: content after the opening delimiter (compile error) ───
// String bad = """Hello
//         World""";

// Correct: line break right after the opening delimiter
String good = """
        Hello
        World""";

// ── Mistake 2: missing space before the line-continuation backslash ──
String sqlBad = """
        SELECT id FROM users\
        WHERE active = true
        """;
// "SELECT id FROM usersWHERE active = true\n"  ← words run together

String sqlGood = """
        SELECT id FROM users \
        WHERE active = true
        """;
// "SELECT id FROM users WHERE active = true\n"

// ── Mistake 3: literal % inside a text block used with formatted() ───
// Wrong — "% c" is parsed as a format specifier and throws at runtime
// String bad = """
//         Completed: %d% complete
//         """.formatted(75);

// Correct — double the percent sign
String progress = """
        Completed: %d%%
        """.formatted(75);
// "Completed: 75%\n"

// ── Mistake 4: assuming trailing spaces survive ──────────────────────
String padded = """
        Name:   \s
        """;
// "Name:    \n" — \s keeps the final space; plain trailing spaces would be stripped