DocumentQueue

java.lang.Object
- org.apache.manifoldcf.crawler.system.DocumentQueue

```
public class DocumentQueue
extends java.lang.Object
```
This class describes a document queue, which has a "stuffer" thread and many "reader" threads. The queue manages thread synchronization so that (a) the "stuffer" thread blocks until queue is empty, and (b) the "reader" threads block if queue is empty. The objects being queued are all QueuedDocumentSet objects.

Field Summary

Fields
Modifier and Type Field Description

static java.lang.String _rcsid

protected java.util.List<QueuedDocumentSet> queue

protected boolean resetFlag

Constructor Summary

Constructors
Constructor Description

DocumentQueue()
Constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`addDocument(QueuedDocumentSet dd)`	Add a document to the queue.
`boolean`	`checkIfEmpty(int n)`	Check if "empty".
`void`	`clear()`	Clear the queue.
`QueuedDocumentSet`	`getDocument(QueueTracker overlapCalculator)`	Pull the best-rated document set off the queue, but wait if there is nothing there.
`void`	`reset()`	Wake up all threads waiting on this queue.

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

- Field Detail
  - _rcsid
```
public static final java.lang.String _rcsid
```
    See Also:
    
    Constant Field Values
  - queue
```
protected final java.util.List<QueuedDocumentSet> queue
```
  - resetFlag
```
protected boolean resetFlag
```
- Constructor Detail
  - DocumentQueue
```
public DocumentQueue()
```
    Constructor.
- Method Detail
  - reset
```
public void reset()
```
    Wake up all threads waiting on this queue. This happens at the beginning of a reset.
  - clear
```
public void clear()
```
    Clear the queue. This happens during a reset.
  - checkIfEmpty
```
public boolean checkIfEmpty(int n)
```
    Check if "empty".
    
    Parameters:
    
    n - is the low-water mark; if the number falls below this, then this method will return true.
  - addDocument
```
public void addDocument(QueuedDocumentSet dd)
```
    Add a document to the queue.
    
    Parameters:
    
    dd - is the document description.
  - getDocument
```
public QueuedDocumentSet getDocument(QueueTracker overlapCalculator)
                              throws java.lang.InterruptedException
```
    Pull the best-rated document set off the queue, but wait if there is nothing there.
    
    Parameters:
    
    overlapCalculator - performs analysis of the document sets on the queue so that we can pick the best one.
    
    Returns:
    
    the document set.
    
    Throws:
    
    java.lang.InterruptedException