dk.netarkivet.common.utils

Class FilterIterator<T,S>

java.lang.Object

dk.netarkivet.common.utils.FilterIterator<T,S>

Type Parameters:

T - Type of Iterator

S - Type of objects returned by the iterator.

All Implemented Interfaces:

Iterator<S>

Direct Known Subclasses:

FileArrayIterator

public abstract class FilterIterator<T,S>
extends Object
implements Iterator<S>

An iterator that filters out and converts items from another iterator. Java 1.5 type: FilterIterator,> filter( o);

Constructor Summary

Constructors

Constructor and Description
FilterIterator(Iterator<T> i) Create a new iterator based on an old one.

Method Summary

Modifier and Type	Method and Description
protected abstract S	filter(T o) Returns the object corresponding to the given object, or null if that object is to be skipped.
boolean	hasNext() Returns true if the iteration has more elements.
S	next() Returns the next element in the iteration.
void	remove() Removes from the underlying collection the last element returned by the iterator (optional operation).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

FilterIterator

public FilterIterator(Iterator<T> i)

Create a new iterator based on an old one. The old one must not contain any null entries.

Parameters:

i - An iterator

Method Detail

filter

protected abstract S filter(T o)

Returns the object corresponding to the given object, or null if that object is to be skipped.

Parameters:

o - An object in the source iterator domain

Returns:

An object in this iterators domain, or null

hasNext

public boolean hasNext()

Returns true if the iteration has more elements. (In other words, returns true if next would return an element rather than throwing an exception.)

Specified by:

hasNext in interface Iterator<S>

Returns:

true if the iterator has more elements.

next

public S next()

Returns the next element in the iteration. Calling this method repeatedly until the hasNext() method returns false will return each element in the underlying collection exactly once.

Specified by:

next in interface Iterator<S>

Returns:

the next element in the iteration.

Throws:

NoSuchElementException - iteration has no more elements.

remove

public void remove()

Removes from the underlying collection the last element returned by the iterator (optional operation). This method can be called only once per call to next. The behavior of an iterator is unspecified if the underlying collection is modified while the iteration is in progress in any way other than by calling this method.

Specified by:

remove in interface Iterator<S>

Throws:

UnsupportedOperationException - if the remove operation is not supported by this Iterator.

IllegalStateException - if the next method has not yet been called, or the remove method has already been called after the last call to the next method.