Frontier

Type Parameters:

E -

All Known Implementing Classes:

FIFOFrontier, LIFOFrontier, LRUFrontier
```
public interface Frontier<E>
```
Data structure for maintaining the worklist set of elements to process in a prescribed order.

Author:

Ben Holland

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`add(E e)`	Adds the element to the frontier Returns true if the element was added, false if the element already existed.
`boolean`	`hasNext()`	Returns true if the frontier is not empty, false otherwise
`E`	`next()`	Returns (and removes) the next element from the frontier
`long`	`size()`	Returns the number of elements on the frontier
`java.lang.String`	`toString()`	Returns a string representation of this frontier collection.

- Method Detail
  - hasNext
```
boolean hasNext()
```
    Returns true if the frontier is not empty, false otherwise
    
    Returns:
  - next
```
E next()
```
    Returns (and removes) the next element from the frontier
    
    Returns:
  - add
```
boolean add(E e)
```
    Adds the element to the frontier Returns true if the element was added, false if the element already existed.
    
    Parameters:
    
    e -
    
    Returns:
  - toString
```
java.lang.String toString()
```
    Returns a string representation of this frontier collection.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
  - size
```
long size()
```
    Returns the number of elements on the frontier
    
    Returns: