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/*
* Copyright 2011-2016 David Karnok
*
* 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 ix;
import java.util.Iterator;
final class IxReduce<T, C> extends IxSource<T, C> {
final IxSupplier<C> initialFactory;
final IxFunction2<C, T, C> reducer;
IxReduce(Iterable<T> source, IxSupplier<C> initialFactory, IxFunction2<C, T, C> reducer) {
super(source);
this.initialFactory = initialFactory;
this.reducer = reducer;
}
@Override
public Iterator<C> iterator() {
return new CollectorIterator<T, C>(source.iterator(), reducer, initialFactory.get());
}
static final class CollectorIterator<T, C> extends IxSourceIterator<T, C> {
final IxFunction2<C, T, C> reducer;
CollectorIterator(Iterator<T> it, IxFunction2<C, T, C> reducer, C value) {
super(it);
this.reducer = reducer;
this.value = value;
}
@Override
protected boolean moveNext() {
Iterator<T> it = this.it;
IxFunction2<C, T, C> f = reducer;
C c = value;
while (it.hasNext()) {
c = f.apply(c, it.next());
}
value = c;
hasValue = true;
done = true;
return true;
}
}
}