// GPars - Groovy Parallel Systems
//
// Copyright © 2008-10  The original author or authors
//
// 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 groovyx.gpars.dataflow.stream;

import java.util.Iterator;
import java.util.NoSuchElementException;

public class FListIterator<T> implements Iterator<T> {

    private FList<T> current;

    public FListIterator(final FList<T> list) {
        current = list;
    }

    @Override
    public boolean hasNext() {
        return !current.isEmpty();
    }

    @Override
    public T next() {
        if (current == null) {
            throw new NoSuchElementException("No element to return from an empty iterator");
        }
        final T next = current.getFirst();
        current = current.getRest();
        return next;
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException("remove() not supported for FList iterators");
    }
}
