001/*
002 * (C) Copyright 2019 Nuxeo (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bdelbosc
018 */
019package org.nuxeo.ecm.core.scroll;
020
021import java.util.Collections;
022import java.util.List;
023import java.util.Map;
024import java.util.NoSuchElementException;
025
026import org.nuxeo.ecm.core.api.scroll.Scroll;
027import org.nuxeo.ecm.core.api.scroll.ScrollRequest;
028
029import com.google.common.collect.Lists;
030
031/**
032 * Returns a static result list of identifiers.
033 *
034 * @since 11.1
035 */
036public class StaticScroll implements Scroll {
037
038    protected StaticScrollRequest request;
039
040    protected List<List<String>> partitions;
041
042    protected int currentPosition;
043
044    protected int nextPosition;
045
046    @Override
047    public void init(ScrollRequest request, Map<String, String> options) {
048        if (!(request instanceof StaticScrollRequest)) {
049            throw new IllegalArgumentException("Requires a StaticScrollRequest");
050        }
051        this.request = (StaticScrollRequest) request;
052        partitions = Lists.partition(this.request.getIdentifiers(), request.getSize());
053        currentPosition = 0;
054    }
055
056    @Override
057    public boolean hasNext() {
058        return currentPosition < partitions.size();
059    }
060
061    @Override
062    public List<String> next() {
063        if (currentPosition >= partitions.size()) {
064            throw new NoSuchElementException();
065        }
066        return partitions.get(currentPosition++);
067    }
068
069    @Override
070    public void close() {
071        partitions = null;
072    }
073
074    @Override
075    public String toString() {
076        return "StaticScroll request: " + request + " currentPos: " + currentPosition + " nextPos: " + nextPosition
077                + " ids: " + partitions;
078    }
079}