001/**
002 * Copyright 2015 DuraSpace, Inc.
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 */
016package org.fcrepo.mint;
017
018import static com.codahale.metrics.MetricRegistry.name;
019import static java.util.UUID.randomUUID;
020
021import java.util.function.Supplier;
022import java.util.stream.IntStream;
023import java.util.StringJoiner;
024
025import org.fcrepo.metrics.RegistryService;
026
027import com.codahale.metrics.Timer;
028
029/**
030 * PID minter that creates hierarchical IDs for a UUID
031 *
032 * @author awoods
033 */
034public class UUIDPathMinter implements Supplier<String> {
035
036    static final Timer timer = RegistryService.getInstance().getMetrics().timer(
037            name(UUIDPathMinter.class, "mint"));
038
039    private static final int DEFAULT_LENGTH = 2;
040
041    private static final int DEFAULT_COUNT = 4;
042
043    private final int length;
044
045    private final int count;
046
047    /**
048     * Configure the path minter using some reasonable defaults for the length
049     * and count of the branch nodes
050     */
051    public UUIDPathMinter() {
052        this(DEFAULT_LENGTH, DEFAULT_COUNT);
053    }
054
055    /**
056     * Configure the path minter for the length of the keys and depth of the
057     * branch node prefix
058     *
059     * @param length how long the branch node identifiers should be
060     * @param count how many branch nodes should be inserted
061     */
062    public UUIDPathMinter(final int length, final int count) {
063        super();
064        this.length = length;
065        this.count = count;
066    }
067
068    /**
069     * Mint a unique identifier as a UUID
070     *
071     * @return uuid
072     */
073    @Override
074    public String get() {
075
076        try (final Timer.Context context = timer.time()) {
077            final String s = randomUUID().toString();
078
079            if (length == 0 || count == 0) {
080                return s;
081            }
082
083            final StringJoiner joiner = new StringJoiner("/", "", "/" + s);
084            IntStream.rangeClosed(0, count - 1)
085                     .forEach(x -> joiner.add(s.substring(x * length, (x + 1) * length)));
086
087            return joiner.toString();
088        }
089    }
090}