UrlCache

All Implemented Interfaces:
```
public interface UrlCache

                    
```
The url cache holds urls.
A url cache contains several queues for different purpose: reentrant, non-reentrant and n-reentrant. A reentrant queue accepts the same url multiple times, a non-reentrant queue accepts the same url only once, and an n-reentrant queue accepts the same url for n times at most.
The URL cache is expected to be very large and items may be loaded from external sources such as MongoDB.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description

Field Summary

Fields
Modifier and Type	Field	Description

Constructor Summary

Constructors
Constructor	Description

Enum Constant Summary

Enum Constants
Enum Constant	Description

Method Summary

Modifier and Type	Method	Description
`abstract Unit`	`removeDeceased()`	Remove dead urls.
`abstract Unit`	`clear()`	Clear the local cache.
`Unit`	`deepClear()`	Clear both the local cache and external source.
`abstract String`	`getName()`	The cache name
`abstract Integer`	`getPriority()`	The priority
`abstract Queue<UrlAware>`	`getNonReentrantQueue()`	A non-reentrant queue accepts the same url only once
`abstract Queue<UrlAware>`	`getNReentrantQueue()`	An n-reentrant queue accepts the same url for n times at most
`abstract Queue<UrlAware>`	`getReentrantQueue()`	A reentrant queue accepts the same url multiple times
`List<Queue<UrlAware>>`	`getQueues()`
`Integer`	`getSize()`
`Integer`	`getExternalSize()`
`Integer`	`getEstimatedExternalSize()`
`Integer`	`getEstimatedSize()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
- Method Detail
  - removeDeceased
```
 abstract Unit removeDeceased()
```
    Remove dead urls.
  - clear
```
 abstract Unit clear()
```
    Clear the local cache.
  - deepClear
```
 Unit deepClear()
```
    Clear both the local cache and external source.
  - getName
```
 abstract String getName()
```
    The cache name
  - getPriority
```
 abstract Integer getPriority()
```
    The priority
  - getNonReentrantQueue
```
 abstract Queue<UrlAware> getNonReentrantQueue()
```
    A non-reentrant queue accepts the same url only once
  - getNReentrantQueue
```
 abstract Queue<UrlAware> getNReentrantQueue()
```
    An n-reentrant queue accepts the same url for n times at most
  - getReentrantQueue
```
 abstract Queue<UrlAware> getReentrantQueue()
```
    A reentrant queue accepts the same url multiple times
  - getQueues
```
 List<Queue<UrlAware>> getQueues()
```
  - getSize
```
 Integer getSize()
```
  - getExternalSize
```
 Integer getExternalSize()
```
  - getEstimatedExternalSize
```
 Integer getEstimatedExternalSize()
```
  - getEstimatedSize
```
 Integer getEstimatedSize()
```