HelpUrl (webmagic 1.0.0-SNAPSHOT API)

```
@Retention(RUNTIME)
@Target(TYPE)
public @interface HelpUrl
```
Define the 'help' url patterns for class.
All urls matching the pattern will be crawled and but not extracted for new objects.

Since:

0.2.0

Author:

code4crafter@gmail.com

- Required Element Summary
  
  Required Elements
  Modifier and Type Required Element Description
  
  java.lang.String[] value
  The url patterns to crawl.
- Optional Element Summary
  
  Optional Elements
  Modifier and Type Optional Element Description
  
  java.lang.String sourceRegion
  Define the region for url extracting.

- Element Detail
  - value
```
java.lang.String[] value
```
    The url patterns to crawl.
    Use regex expression with some changes:
    "." stand for literal character "." instead of "any character".
    "*" stand for any legal character for url in 0-n length ([^"'#]*) instead of "any length".
    
    Returns:
    
    the url patterns for class
- - sourceRegion
```
java.lang.String sourceRegion
```
    Define the region for url extracting.
    Only support XPath.
    When sourceRegion is set, the urls will be extracted only from the region instead of entire content.
    
    Returns:
    
    the region for url extracting
    
    Default:
    
    ""