# (DD18) Business Logic — Example.demonstrateStringStripTrailing() [6 LOC]

| Field | Value |
|-------|-------|
| Fully Qualified Name | `io.github.biezhi.java11.string.Example` |
| Layer | Utility |
| Module | `string` (Package: `io.github.biezhi.java11.string`) |

## 1. Role

### Example.demonstrateStringStripTrailing()

This method is a small demonstration routine that showcases the JDK 11 `String.stripTrailing()` API. Its business purpose is not to transform a persistent domain object or to execute transactional processing, but to illustrate how trailing whitespace is removed from a user-visible text sample while preserving leading whitespace. In practical terms, it serves as a reference example for developers validating string normalization behavior in presentation or input-cleanup scenarios.

The method follows a simple presentation pattern: it prepares a sample string, prints a header describing the API being demonstrated, and then prints the result of applying trailing-space trimming. It does not branch into multiple service categories, perform routing, or delegate to external components beyond the shared `writeHeader()` utility in the same class. Within the larger module, it acts as an educational entry point for the `stripTrailing()` feature alongside sibling methods that demonstrate related JDK 11 string APIs such as `strip()`, `stripLeading()`, and `isBlank()`.

## 2. Processing Pattern (Detailed Business Logic)

```mermaid
flowchart TD
    START["demonstrateStringStripTrailing()"]
    STEP1["Set originalString = '  biezhi.me  23333  '"]
    STEP2["Call writeHeader('String.stripTrailing() on ' + originalString)"]
    STEP3["Call System.out.println('' + originalString.stripTrailing() + '')"]
    END_NODE["Return / Next"]
    START --> STEP1
    STEP1 --> STEP2
    STEP2 --> STEP3
    STEP3 --> END_NODE
```

The method has a single linear flow with no conditional branching, looping, or exception handling. It initializes a sample string containing both leading and trailing spaces, passes a descriptive label to the shared header writer, and then emits the stripped result to standard output. The key business behavior is the trailing-whitespace normalization performed by `String.stripTrailing()`.

## 3. Parameter Analysis

| No | Parameter Name | Type | Business Description |
|----|---------------|------|---------------------|
| - | (none) | - | - |

External state read by the method:
- The class-level private utility method `writeHeader(String headerText)`.
- Standard output via `System.out.println(...)`.
- The JDK 11 `String.stripTrailing()` implementation, which determines how trailing whitespace is removed.

## 4. CRUD Operations / Called Services

### Pre-computed evidence from code analysis graph:

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| - | `Example.writeHeader` | Example | - | Calls `writeHeader` in `Example` |

Analyze all method calls within this method and classify each as a CRUD operation.

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| R | `Example.writeHeader` | Example | Console / standard output | Writes a formatted header describing the `String.stripTrailing()` demonstration |
| R | `System.out.println` | JDK StdOut | Console / standard output | Prints the stripped string result for visual verification |
| R | `String.stripTrailing` | JDK 11 String API | In-memory string value | Reads the current string value and returns a trailing-whitespace-trimmed representation |

## 5. Dependency Trace

Trace who calls this method and what this method ultimately calls.

| # | Caller (Screen/Batch) | Call Chain (Full Path to this Method) | Terminal (SC / CRUD / Entity) |
|---|----------------------|--------------------------------------|-------------------------------|
| 1 | `Example.main` | `Example.main` -> `Example.demonstrateStringStripTrailing` | `writeHeader [R] Console / standard output; String.stripTrailing [R] In-memory string value; System.out.println [R] Console / standard output` |

## 6. Per-Branch Detail Blocks

This method contains a single straight-line block with no branching structures.

**Block 1** — [SEQUENCE] (L69-L74)

> Demonstrates trailing-whitespace trimming on a fixed sample string and prints both the header and the normalized result.

| # | Type | Code |
|---|------|------|
| 1 | SET | `String originalString = "  biezhi.me  23333  ";` |
| 2 | CALL | `writeHeader("String.stripTrailing() on '" + originalString + "'");` |
| 3 | EXEC | `System.out.println("'" + originalString.stripTrailing() + "'");` |

## 7. Glossary

| Term | Type | Business Meaning |
|------|------|------------------|
| `stripTrailing` | JDK API | Removes trailing whitespace from a string while preserving leading whitespace |
| `strip` | JDK API | Removes leading and trailing whitespace from a string |
| `stripLeading` | JDK API | Removes leading whitespace from a string while preserving trailing whitespace |
| `isBlank` | JDK API | Tests whether a string is empty or contains only whitespace |
| `writeHeader` | Utility method | Shared console-formatting helper that prints a title framed by separator lines |
| `originalString` | Local variable | Sample input string used to demonstrate whitespace trimming behavior |
| `System.out.println` | Technical output | Console output channel used to display the demonstration result |
| JDK 11 | Platform version | Java platform release that introduced the `String.stripTrailing()` API |
| Utility | Layer | Shared helper or demonstration code that is not tied to a specific business domain entity |