001/*
002 * Licensed to DuraSpace under one or more contributor license agreements.
003 * See the NOTICE file distributed with this work for additional information
004 * regarding copyright ownership.
005 *
006 * DuraSpace licenses this file to you under the Apache License,
007 * Version 2.0 (the "License"); you may not use this file except in
008 * compliance with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.fcrepo.kernel.api.services.functions;
019
020import static java.util.UUID.randomUUID;
021
022import java.util.StringJoiner;
023import java.util.stream.IntStream;
024
025/**
026 * Unique value minter that creates hierarchical IDs from a UUID
027 *
028 * @author rdfloyd
029 * @author whikloj
030 */
031public class ConfigurableHierarchicalSupplier implements UniqueValueSupplier {
032
033    private static final int DEFAULT_LENGTH = 0;
034    private static final int DEFAULT_COUNT = 0;
035
036    private final int length;
037    private final int count;
038
039
040    /**
041     * Mint a hierarchical identifier with args to control length and count of the pairtree. A length or count of ZERO
042     * will return a non-hierarchical identifier.
043     *
044     * @param desiredLength the desired length of pairtree parts
045     * @param desiredCount the desired number of pairtree parts
046     */
047    public ConfigurableHierarchicalSupplier(final int desiredLength, final int desiredCount) {
048        length = desiredLength;
049        count = desiredCount;
050    }
051
052    /**
053     * Mint a unique identifier by default using defaults
054     *
055     */
056    public ConfigurableHierarchicalSupplier() {
057        length = DEFAULT_LENGTH;
058        count = DEFAULT_COUNT;
059    }
060
061    /**
062     * Mint a unique identifier as a UUID
063     *
064     * @return uuid
065     */
066    @Override
067    public String get() {
068
069        final String s = randomUUID().toString();
070        final String id;
071
072        if (count > 0 && length > 0) {
073            final StringJoiner joiner = new StringJoiner("/", "", "/" + s);
074
075            IntStream.rangeClosed(0, count - 1)
076            .forEach(x -> joiner.add(s.substring(x * length, (x + 1) * length)));
077            id = joiner.toString();
078        } else {
079            id = s;
080        }
081        return id;
082    }
083}