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/*
 *  Copyright (C) 2022 github.com/REAndroid
 *
 *  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 com.reandroid.utils.collection;

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

public abstract class IterableIterator implements Iterator {
    private final Iterator iterator;
    private Iterator mCurrent;
    private int mCount;
    private boolean mStop;
    public IterableIterator(Iterator iterator){
        this.iterator = iterator;
    }
    public int getCount() {
        return mCount;
    }
    public void stop(){
        mStop = true;
    }
    public abstract Iterator iterator(E element);

    @Override
    public boolean hasNext() {
        Iterator current = getCurrent();
        return current != null && !mStop && current.hasNext();
    }

    @Override
    public T next() {
        Iterator current = getCurrent();
        if(current == null){
            throw new NoSuchElementException();
        }
        T item = current.next();
        mCount ++;
        return item;
    }

    private Iterator getCurrent(){
        if(mCurrent == null || !mCurrent.hasNext()) {
            mCurrent = null;
            while (iterator.hasNext()) {
                Iterator item = iterator(iterator.next());
                if (item != null && item.hasNext()) {
                    mCurrent = item;
                    break;
                }
            }
        }
        return mCurrent;
    }
}