/**
* Copyright 2013 Oak Ridge National Laboratory
* Author: James Horey <horeyjl@ornl.gov>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
**/
package gov.ornl.keva.core;
/**
* Java libs.
**/
import java.util.Collections;
import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Comparator;
/**
* Selects a single item from a set of choices.
*/
public class MinimumIterator<E> extends StreamIterator<E> {
private boolean decisionMade;
protected List<E> choices;
/**
* Construct an empty iterator.
*/
public MinimumIterator(Comparator<E> comparator) {
super(comparator);
decisionMade = false;
choices = new ArrayList<>();
}
/**
* Get the number of elements being processed.
*/
@Override public int size() {
return 1;
}
/**
* Indicate whether we have another element.
*/
@Override public boolean hasNext() {
return
choices.size() > 0 &&
!decisionMade;
}
/**
* Fetch the next element.
*/
@Override public E next() {
E e = Collections.max(choices, comparator);
decisionMade = true;
return e;
}
/**
* Add a new iterator to the list of choices.
*/
public void addAll(List<StreamIterator<E>> iters) {
for(StreamIterator<E> iter : iters) {
if(iter.hasNext()) {
choices.add(iter.next());
}
}
}
}