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