src/main/java/org/apache/sling/query/impl/iterator/FilteringIterator.java

/*-
 * 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.sling.query.impl.iterator;

import java.util.Iterator;
import java.util.function.Predicate;

import org.apache.sling.query.api.internal.Option;

public class FilteringIterator<T> extends AbstractIterator<Option<T>> {

    private final Iterator<Option<T>> iterator;

    private final Predicate<T> predicate;

    public FilteringIterator(Iterator<Option<T>> iterator, Predicate<T> predicate) {
        this.iterator = iterator;
        this.predicate = predicate;
    }

    @Override
    protected Option<T> getElement() {
        while (iterator.hasNext()) {
            Option<T> element = iterator.next();
            if (element.isEmpty() || predicate.test(element.getElement())) {
                return element;
            } else {
                return Option.empty(element.getArgumentId());
            }
        }
        return null;
    }
}