/*  __    __  __  __    __  ___
 * \  \  /  /    \  \  /  /  __/
 *  \  \/  /  /\  \  \/  /  /
 *   \____/__/  \__\____/__/
 *
 * Copyright 2014-2020 Vavr, http://vavr.io
 *
 * 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 io.vavr.collection;

import java.util.NoSuchElementException;

/**
 * Provides a common {@link Object#toString()} implementation.
 * <p>
 * {@code equals(Object)} and {@code hashCode()} are intentionally not overridden in order to prevent this iterator
 * from being evaluated. In other words, (identity-)equals and hashCode are implemented by Object.
 *
 * @param <T> Component type
 * @author Daniel Dietrich
 */
abstract class AbstractIterator<T> implements Iterator<T> {

    @Override
    public String toString() {
        return stringPrefix() + "(" + (isEmpty() ? "" : "?") + ")";
    }

    protected abstract T getNext();

    @Override
    public final T next() {
        if (!hasNext()) {
            throw new NoSuchElementException("next() on empty iterator");
        }
        return getNext();
    }
}
