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/*********************************************************************************
 *                                                                               *
 * The MIT License (MIT)                                                         *
 *                                                                               *
 * Copyright (c) 2015-2022 aoju.org Greg Messner and other contributors.         *
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 * of this software and associated documentation files (the "Software"), to deal *
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 * copies of the Software, and to permit persons to whom the Software is         *
 * furnished to do so, subject to the following conditions:                      *
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 * The above copyright notice and this permission notice shall be included in    *
 * all copies or substantial portions of the Software.                           *
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 * THE SOFTWARE.                                                                 *
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package org.aoju.bus.gitlab;

import java.util.Collections;
import java.util.Iterator;
import java.util.Spliterator;
import java.util.function.Consumer;

class PagerSpliterator implements Spliterator {

    private Pager pager;

    private Iterator elements;

    PagerSpliterator(Pager pager) {
        this.pager = pager;
        if (pager.hasNext()) {
            elements = this.pager.next().iterator();
        } else {
            elements = Collections.emptyIterator();
        }
    }

    @Override
    public boolean tryAdvance(Consumer action) {
        if (action == null) {
            throw new NullPointerException("Action is null");
        }
        if (elements.hasNext()) {
            action.accept(elements.next());
            return true;
        } else if (pager.hasNext()) {
            elements = pager.next().iterator();
            if (elements.hasNext()) {
                action.accept(elements.next());
                return true;
            }
        }
        return false;
    }

    @Override
    public Spliterator trySplit() {
        return null;
    }

    @Override
    public long estimateSize() {
        return pager.getTotalItems();
    }

    @Override
    public int characteristics() {
        return SIZED | NONNULL;
    }
}