001/*
002 * The MIT License
003 *
004 * Copyright (c) 2013-2016, Ninja Squad
005 *
006 * Permission is hereby granted, free of charge, to any person obtaining a copy
007 * of this software and associated documentation files (the "Software"), to deal
008 * in the Software without restriction, including without limitation the rights
009 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010 * copies of the Software, and to permit persons to whom the Software is
011 * furnished to do so, subject to the following conditions:
012 *
013 * The above copyright notice and this permission notice shall be included in
014 * all copies or substantial portions of the Software.
015 *
016 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
017 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
018 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
019 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
020 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
021 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
022 * THE SOFTWARE.
023 */
024
025package com.ninja_squad.dbsetup.generator;
026
027import com.ninja_squad.dbsetup.util.Preconditions;
028
029/**
030 * A {@link ValueGenerator} that returns a string prefix followed by a sequence number, optionally left-padded
031 * with 0 to ensure a correct ordering (for example: CODE_001, CODE_002, etc.). Instances of this generator
032 * are created by {@link ValueGenerators#stringSequence(String)}.
033 * @author JB
034 */
035public final class StringSequenceValueGenerator implements ValueGenerator<String> {
036    private String prefix;
037    private long next;
038    private int increment;
039
040    /**
041     * The length of the number once padded. 0 if no padding must be applied
042     */
043    private int paddedNumberLength;
044
045    StringSequenceValueGenerator(String prefix) {
046        this(prefix, 1L, 1, 0);
047    }
048
049    private StringSequenceValueGenerator(String prefix, long next, int increment, int paddedNumberLength) {
050        this.prefix = prefix;
051        this.next = next;
052        this.increment = increment;
053        this.paddedNumberLength = paddedNumberLength;
054    }
055
056    /**
057     * Tells the generator to left-pad the number it generates with 0 until the length of the number is the given
058     * length. For example, passing 3 to this method will generate numbers 001, 002, 003, 004, etc. If the generated
059     * number, before padding, has a length already equal or larger that the given length, the number is not padded.
060     * @param paddedNumberLength the length of the number once padded. Must be &gt; 0.
061     * @return this instance, for chaining
062     */
063    public StringSequenceValueGenerator withLeftPadding(int paddedNumberLength) {
064        Preconditions.checkArgument(paddedNumberLength > 0, "paddedNumberLength must be > 0");
065        this.paddedNumberLength = paddedNumberLength;
066        return this;
067    }
068
069    /**
070     * Tells the generator to avoid left-padding the number it generates with 0
071     * @return this instance, for chaining
072     */
073    public StringSequenceValueGenerator withoutLeftPadding() {
074        this.paddedNumberLength = 0;
075        return this;
076    }
077
078    /**
079     * Restarts the sequence at the given value
080     * @param start the new starting value of the sequence
081     * @return this instance, for chaining
082     */
083    public StringSequenceValueGenerator startingAt(long start) {
084        this.next = start;
085        return this;
086    }
087
088    /**
089     * Increments the number by the given increment.
090     * @return this instance, for chaining
091     */
092    public StringSequenceValueGenerator incrementingBy(int increment) {
093        this.increment = increment;
094        return this;
095    }
096
097    @Override
098    public String nextValue() {
099        long number = next;
100        next += increment;
101        return prefix + leftPadIfNecessary(number);
102    }
103
104    private String leftPadIfNecessary(long number) {
105        String numberAsString = Long.toString(number);
106        if (numberAsString.length() >= paddedNumberLength) {
107            return numberAsString;
108        }
109        StringBuilder builder = new StringBuilder(paddedNumberLength);
110        for (int i = 0; i < paddedNumberLength - numberAsString.length(); i++) {
111            builder.append('0');
112        }
113        return builder.append(numberAsString).toString();
114    }
115
116    @Override
117    public String toString() {
118        return "StringSequenceValueGenerator["
119               + "prefix='" + prefix + '\''
120               + ", next=" + next
121               + ", increment=" + increment
122               + ", paddedNumberLength=" + paddedNumberLength
123               + "]";
124    }
125}