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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.kafka.common.utils;

import java.util.Iterator;
import java.util.List;

public class CircularIterator implements Iterator {
    int i = 0;
    private List list;

    public CircularIterator(List list) {
        if (list.isEmpty()) {
            throw new IllegalArgumentException("CircularIterator can only be used on non-empty lists");
        }
        this.list = list;
    }

    @Override
    public boolean hasNext() {
        return true;
    }

    @Override
    public T next() {
        T next = list.get(i);
        i = (i + 1) % list.size();
        return next;
    }

    public T peek() {
        return list.get(i);
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException();
    }
}